diff --git a/gitnexus/bench/import-target/baselines.json b/gitnexus/bench/import-target/baselines.json
index 8e05ecfe7..b55ae8ccd 100644
--- a/gitnexus/bench/import-target/baselines.json
+++ b/gitnexus/bench/import-target/baselines.json
@@ -1,8 +1,8 @@
 {
   "_what": "Baselines for bench/import-target/measure.mjs \u2014 EVERY import-target resolver registered in SCOPE_RESOLVERS, on one shared corpus, plus csharp a second time WITH csproj configs. One entry per registered language and one more for the csproj arm, no registered language ungated \u2014 and that is ASSERTED rather than asserted-in-a-comment, which is also why no roster of language names is kept in this prose to go stale: measure.mjs derives its language list from a LANG_REGISTRY table and a --check inventory arm reconciles that table against SCOPE_RESOLVERS in both directions. A C/C++ #include is an import site for this purpose and is gated like every other registered language. csharp and csharp_csproj resolve the IDENTICAL file corpus (buildFiles aliases the two) and differ in exactly one thing: whether csharpConfigs is supplied. Without that second arm the csproj namespace-directory index ships unmeasured, because every C# import in the no-csproj arm returns before reaching it. C and C++ follow that same precedent for a different context \u2014 their HEADERS arrive through resolutionConfig rather than through allFilePaths, and augmentedFilePaths unions the two once per pass, so the corpus is split at newPass rather than pre-merged. The first nine were added as their own O(imports x files) scans were indexed away (#2877/#2878/#2879/#2880, #2872, #2901, #2902, #2908) and this is the forward guard on each; the other eight were ungated until now, and PR #2911 \u2014 JavaScript reaching suffixResolve with no index at all, 25972 us per import at 8000 files \u2014 is what that costs.",
-  "_fingerprint_note": "Per-language sha256 over every distinct fromFile|target -> resolved target. A change here is a BEHAVIOUR change: the resolver returned a different target set, and IMPORTS/CALLS edges moved. Explain it, never re-baseline to make CI green. For the languages these PRs changed, the pre-change implementations produce these same values on this corpus at both 400 and 1600 files \u2014 that is what makes the index hoist a performance change. The tie-break-level proof lives in test/unit/scope-resolution/import-target-index-parity.test.ts (verbatim copies of the pre-change code, diffed) for Kotlin in test/unit/scope-resolution/kotlin/kotlin-import-target-parity.test.ts, and for the four resolvers added there in test/unit/scope-resolution/{php,java,cobol}-import-target-parity.test.ts and test/unit/import-resolvers/csharp-csproj-parity.test.ts, and for JavaScript in test/unit/scope-resolution/javascript-import-target-parity.test.ts (a differential over 211200 old-vs-new pairs, PR #2911). The eight languages added last have no per-language parity harness against a pre-change implementation and do NOT need one: nothing about their resolution changed, so there is no before to diff against. Their fingerprints are pure forward guards, minted from the current implementations, and their adapter-boundary index reuse is covered for every registered language at once by test/unit/scope-resolution/import-target-index-reuse.contract.test.ts. NOTE for csharp_csproj: on this corpus the #2902 indexed leg (step 3 of resolveCSharpImportInternal) is reached by 2221 of the 3200 small-arm imports but answers null for every one of them \u2014 the 979 that resolve do so at step 2 \u2014 so this fingerprint pins that legs cost and its null answers, while its positive tie-breaks (first-occurrence, unanchored substring, iteration order) are pinned by csharp-csproj-parity.test.ts. NOTE for kotlin: all five kotlin fingerprints were re-baselined in #2881, the one deliberate behaviour change any language in this file has had. `getKotlinFileIndex` no longer requires a file's package directory to be the FIRST occurrence of that name in its own path, so the unique arm's `d % 7` nested slice (`mod{d}/src/main/kotlin/com/example/pkg{d}/inner/pkg{d}`) now belongs to package `pkg{d}` and its wildcard imports resolve: resolved 1100 -> 1153 small and deep, 4456 -> 4681 large. The collide arm needed a CORPUS edit alongside it, not just a new number — its `d % 7` slice deliberately imported `com.example.vendor{d}`, a package that exists nowhere, purely to mirror the unique arm's nested-slice MISS, so leaving it would have left collide at 1100 against small's 1153 and broken the same-workload invariant the arm is built on (that assertion is what caught it). It now uses the same `com.example.models.*` spelling as the rest of the arm, which is why its distinct_outcomes fell (2775 -> 2744, 11087 -> 10961): one shared target instead of one per d. The record-level evidence for the resolver change — 235 of 19968 records moved, 54 null -> resolved, 0 buckets losing a member — is in bench/kotlin-import-target/baselines.json `_provenance`. The kotlin heap_reading_bytes and heap_ceiling_bytes moved with it, together as `_heap_reading_note` requires: 48073096 -> 48200224 bytes_large (+127128, +0.264%), ceiling still exactly 1.5x. Small, and it is worth saying WHY it is small rather than reading the number as evidence that the change is cheap. `dirChildren` grows by one entry per component-suffix the old rule used to skip, and this arm can only see part of that: the heap corpus is built with HEAP_PAD 8, which prefixes every path with `d0/…/d7/`, so no path can begin with a suffix of its own directory and the leading-segment half of the old rule is structurally invisible here. What moves the reading is the `d % 7` nested slice alone. Read +0.264% as this arm's ceiling on the effect, not as the effect.",
+  "_fingerprint_note": "Per-language sha256 over every distinct fromFile|target -> resolved target. A change here is a BEHAVIOUR change: the resolver returned a different target set, and IMPORTS/CALLS edges moved. Explain it, never re-baseline to make CI green. For the languages these PRs changed, the pre-change implementations produce these same values on this corpus at both 400 and 1600 files \u2014 that is what makes the index hoist a performance change. The tie-break-level proof lives in test/unit/scope-resolution/import-target-index-parity.test.ts (verbatim copies of the pre-change code, diffed) for Kotlin in test/unit/scope-resolution/kotlin/kotlin-import-target-parity.test.ts, and for the four resolvers added there in test/unit/scope-resolution/{php,java,cobol}-import-target-parity.test.ts and test/unit/import-resolvers/csharp-csproj-parity.test.ts, and for JavaScript in test/unit/scope-resolution/javascript-import-target-parity.test.ts (a differential over 211200 old-vs-new pairs, PR #2911). The eight languages added last have no per-language parity harness against a pre-change implementation and do NOT need one: nothing about their resolution changed, so there is no before to diff against. Their fingerprints are pure forward guards, minted from the current implementations, and their adapter-boundary index reuse is covered for every registered language at once by test/unit/scope-resolution/import-target-index-reuse.contract.test.ts. NOTE for csharp_csproj: on this corpus the #2902 indexed leg (step 3 of resolveCSharpImportInternal) is reached by 2221 of the 3200 small-arm imports but answers null for every one of them \u2014 the 979 that resolve do so at step 2 \u2014 so this fingerprint pins that legs cost and its null answers, while its positive tie-breaks (unanchored substring, iteration order) are pinned by csharp-csproj-parity.test.ts. NOTE for kotlin, go, csharp and java: twenty fingerprints across these four languages were re-baselined in #2881, the one deliberate behaviour change any language in this file has had. It landed in two steps and the second is the reason the first is not a special case: Kotlin first, then the shared package-dir-index (go, java, csharp) and the csproj namespace index once the same rule was found live there. `getKotlinFileIndex` no longer requires a file's package directory to be the FIRST occurrence of that name in its own path, so the unique arm's `d % 7` nested slice (`mod{d}/src/main/kotlin/com/example/pkg{d}/inner/pkg{d}`) now belongs to package `pkg{d}` and its wildcard imports resolve: resolved 1100 -> 1153 small and deep, 4456 -> 4681 large. The collide arm needed a CORPUS edit alongside it, not just a new number \u2014 its `d % 7` slice deliberately imported `com.example.vendor{d}`, a package that exists nowhere, purely to mirror the unique arm's nested-slice MISS, so leaving it would have left collide at 1100 against small's 1153 and broken the same-workload invariant the arm is built on (that assertion is what caught it). It now uses the same `com.example.models.*` spelling as the rest of the arm, which is why its distinct_outcomes fell (2775 -> 2744, 11087 -> 10961): one shared target instead of one per d. The record-level evidence for the resolver change \u2014 235 of 19968 records moved, 54 null -> resolved, 0 buckets losing a member \u2014 is in bench/kotlin-import-target/baselines.json `_provenance`. The kotlin heap_reading_bytes and heap_ceiling_bytes moved with it, together as `_heap_reading_note` requires: 48073096 -> 48200224 bytes_large (+127128, +0.264%), ceiling still exactly 1.5x. Small, and it is worth saying WHY it is small rather than reading the number as evidence that the change is cheap. `dirChildren` grows by one entry per component-suffix the old rule used to skip, and this arm can only see part of that: the heap corpus is built with HEAP_PAD 8, which prefixes every path with `d0/\u2026/d7/`, so no path can begin with a suffix of its own directory and the leading-segment half of the old rule is structurally invisible here. What moves the reading is the `d % 7` nested slice alone. Read +0.264% as this arm's ceiling on the effect, not as the effect. GO NEEDED A CORPUS EDIT TO BE GATED AT ALL. Its nested slice was `src/pkg{d}/internal/pkg{d}`, repeating only the LAST segment, while a Go query addresses the whole package path `src/pkg{d}` \u2014 so the directory never even ended with the query and the first-occurrence rule was never reached. Every go arm sat unchanged through the resolver fix. `uniqueDir`/`collideDir` now repeat the shape at the granularity Go actually queries (`src/pkg{d}/internal/src/pkg{d}`, `svc{d}/internal/sub/svc{d}/internal`), which is what moved go from 979 to 1153 resolved and bumped `languages.go.heap.path_segments` 13 -> 14. The general lesson: a corpus that carries a shape the QUERY cannot express does not gate that shape. CSHARP AND JAVA HIT THE SAME COLLIDE-ARM TRAP AS KOTLIN. Both collide arms sent their `d % 7` slice to a namespace that exists nowhere (`App.Src{d}.Vendor`, `com.svc{d}.vendor`) purely to MIRROR the unique arm's nested-slice miss; once that miss became a hit, collide sat at 979/1100 against small's 1153 and the same-workload assertion failed. Both now use the same spelling as the rest of their arm. HEAP: only `csharp_csproj` moved measurably (73703384 -> 73116520, -0.79%, stable across runs), re-recorded here with its ceiling; the step-2 filter change alters which lazily-built `getFilesInDir` maps the probe import forces, and that laziness is what the reading sees. Everything else sat within +/-0.03%. Note that `_heap_reading_note`'s claim that these readings 'reproduce to the byte across processes on one box' did NOT hold on the box this was measured on: go, dart, ruby, python, php and cpp all wandered by a few hundred to a few thousand bytes between processes with no code change touching them. Treat sub-0.05% movement as jitter, not signal.",
   "_shape_note": "files/imports/resolved/distinct_outcomes AND the fingerprint are asserted exactly, per scale. A fingerprint alone cannot tell a legitimate resolution change from a corpus quietly shrunk below the size at which the timing arms can see anything; conversely the counts alone cannot see a defect confined to one arm, because the arms differ only in path padding and directory layout and both of those are count-neutral by design. Two cross-arm assertions close the remaining hole: the deep and collide arms must resolve exactly what small resolves (they are the same workload), and each of their fingerprints must DIFFER from small's (they are not the same corpus). Without the second, setting DEEP_PAD to 0 \u2014 which deletes the entire depth arm \u2014 moves no asserted number and prints PASS; the same is true of a collideDir that forwards to uniqueDir. THE HEAP ARM IS ASSERTED THE SAME WAY, by the same loop, and was not before: files_small, files_large, path_segments and probe decide WHAT it measures, and every one of them was reported and compared to nothing. Swapping HEAP_PROBE_TARGET.csharp_csproj for a target matching no CSPROJ_CONFIGS rootNamespace skips the whole config loop, so the getFilesInDir and getInsensitive legs never run and the arm the header calls the witness that the read pattern IS the footprint quietly becomes a two-map arm \u2014 73703384 -> 59921216 B, ratio 1.017 -> 1.011, ceiling and floor both still passing and --check still exiting 0. Setting HEAP_SMALL equal to HEAP_LARGE is the same hole from the other side: ratio goes to ~1.0 by construction and bytes_large never moves. bytes_small and bytes_large are deliberately NOT asserted for equality \u2014 heap_ceiling_bytes and the heap_reading_bytes floor bound them with ~50% either way, because heapUsed accounting moves across platforms and Node majors and an exact byte assertion would be a re-baseline per runner. THE CONTEXT ARM IS ASSERTED THE SAME WAY, by the same loop, and more strictly than either: target, with_context and without_context are exact strings with no tolerance at all, because the arm resolves one import over a three-file corpus and has no measurement noise to tolerate. A separate check requires the last two to DIFFER, for the same reason deep.fingerprint must differ from small.fingerprint \u2014 a probe on which both call shapes agree asserts one number twice. Both halves run through resolveOne, so what the arm gates is this bench threading run.ts's fifth argument, not the resolvers' behaviour.",
-  "_arms_note": "Five timing arms, one memory arm and one deterministic arm elsewhere, because none of them gates alone. scaling_ratio (t_large/t_small)/(1600/400) catches cost growing with FILE COUNT \u2014 the #2877-#2880, #2901, #2902 and #2908 regressions themselves; every one of those legs was Theta(files) per import, so a revert scores ~4 here by construction. depth_ratio (t_deep/t_small at a FIXED file count, ~6x the path components) catches cost growing with path DEPTH, which scaling_ratio divides out and structurally cannot see; buildSuffixIndex (C#, Ruby, PHP, Java) and Kotlin suffixByStem emit one entry per component, so they legitimately sit above 1.0 while Go, Dart and COBOL, whose indexes are depth-free, sit at ~1.0. csharp's depth_budget has now been retightened twice for the same reason, and the second time it did lock the win in. It was 5 against a then-measured 3.318; #2903 made buildSuffixIndex's dirMap lazy and it became 3.5 against 2.31, with the file stating plainly that 3.5 did NOT lock that win in because a revert to an eager dirMap scores 3.318 and passes. Extending the laziness to the two SUFFIX maps drops it again, to 1.438 (java likewise 2.214 -> 1.402), because the deep arm has ~6x the path components and an O(files x depth) build of a map the no-csproj leg never reads is exactly the cost that scales with depth. Both are now 2.2, which is this file's 1.5x convention against measurements whose own peak-to-peak over 4 runs is 1.04x and 1.07x \u2014 and 2.2 DOES lock it in: an eager rebuild scores 2.3+ and fails. The other fifteen depth budgets sit at 1.37-1.75x measured and are unchanged. collide_scaling_ratio is the same measurement on a SHARED-LEAF layout (svcN/internal, SrcN/Models, com/example/model in every service, a repeated mod0.dart/mod0.rb/Mod0.cpy basename) carrying an identical file, import and resolved count: the small/large/deep arms mint one directory name per index, so every index bucket in them holds exactly ONE entry (measured: max last-segment bucket 1 and max matching directories 1 for go and csharp at 400 and 1600 files; max basename bucket 1 for dart and ruby), and bucket cardinality is the only non-constant term the new indexes have. On the shared-leaf shape go, csharp, dart and java legitimately score 2.1-3.9 because the bucket grows with the file count BY CONSTRUCTION \u2014 this is a limit on the SCOPE of the \"independent of corpus size\" claim, not a regression (the indexed code is still faster there than the pre-change full scan); their collide budgets say so honestly instead of pretending 1.8. Ruby, Kotlin, PHP and COBOL answer from keyed maps and are collision-immune, so they keep the linear 1.8 budget and that immunity is the assertion. csharp_csproj is the one arm that runs the other way: its shared leaf collapses dirsByLastSegment to the single key Models, so the slash-free sweep (see CSPROJ_CONFIGS) is CHEAPER on the collide layout than on the unique one and its expensive scale arm is large, not collide_large. Its 1.8 collide budget is therefore the linear one, and the arm that carries its real cost is the unique one. The collide arm is also the only arm that reaches filesDirectlyInPkgDir's dirCount > 1 merge (go: 388 multi-directory calls at 400 files, up to 9 directories; 1517 at 1600 files, up to 34) and the only one that reaches COBOL's copybook-over-source tier tie-break, which needs one bookname to name two files. small_ms_ceiling and collide_ms_ceiling are ABSOLUTE (~4x the measured arm), because a constant-factor regression that grows both scale arms equally passes every ratio. The five arms added here use 4.2x, the middle of the 3.7-4.6x the original five already carry; the two COBOL arms use ~5x, the multiplier dart's sub-1 ms arm has always carried, because a fixed scheduler hiccup is a larger fraction of a smaller number \u2014 measured over 8 runs they sat at 0.25-0.37 ms and 0.18-0.30 ms, and the pre-#2908 two-scans-per-COPY implementation costs ~300 ms on the same arm, so 2.0 and 1.5 still separate fixed from broken by two orders of magnitude. NOISE, measured rather than assumed: depth_ratio divides two sub-3 ms numbers (Dart's are sub-1 ms) and is by far the noisiest arm here, so it set N for the whole file. fastest() is a min-of-N estimator, so N is the knob. Over 22 --check runs on an idle box, peak-to-peak: at N=5 go ran 0.757-1.748 (2.31x) and tripped its own 1.6 budget about 1 run in 20; at N=7 (the kotlin-import-target setting) Dart still ran 0.678-2.043 (3.01x) and tripped once; at N=15 (bench/cfg, bench/schema-pairs, bench/callable-value-flow) every language collapsed to a 1.13-1.26x swing with 22/22 passing. The budgets were NOT widened; the estimator was fixed instead, which is why the headroom above is real rather than granted. N IS NOW PER LANGUAGE, and that is a refinement of the same finding rather than a retreat from it. The overshoot of min-of-K against min-of-15 is a function of the CELL's absolute duration, not of the language: replayed against two independent runs' full sample sets, the worst overshoots at K=7 land on swift.small (0.43 ms, 31.8%) and dart.collide (1.5 ms, 37.6%), while every cell at or above 10 ms overshoots by at most 6.3%. So repsFor() keeps 15 while a language's cheapest arm is under 5 ms and otherwise spends ~150 ms per cell, floored at 7 \u2014 15 for go, csharp, dart, kotlin, java, cobol, swift, rust, python, c and cpp (every language the flakiness above was ever about, cheapest arm 0.19-3.2 ms) and 7-8 for csharp_csproj, ruby, php, javascript, typescript and vue (cheapest arm 20-28 ms). Per LANGUAGE, not per cell, so all five arms of a language share one estimator and the four ratios stay comparisons of like with like. The replay passed all 85 cells on all five gates at 0.4-0.7 of budget and saved 12.8 s and 12.4 s of a 46 s run; min-of-7 also reads slightly HIGHER than min-of-15, so the ceilings get marginally more sensitive rather than less. Confirmed on 4 fresh runs with the adaptive estimator live: every small arm inside 1.12x peak-to-peak and every collide arm inside 1.07x, with the six 7-8 rep languages at 1.008-1.071 \u2014 no worse than the 11 that kept 15. The chosen N is reported per language as `reps`. heap_ceiling_bytes bounds the retained per-pass import index, the only arm here that can see memory: buildSuffixIndex emits maps at O(files x depth), the profile package-dir-index.ts cites #2649 to avoid for itself, and csharp, ruby, php and java all retained NOTHING across imports at BASE (C#'s no-csproj leg and PHP's and Java's every leg re-scanned the raw Set; Ruby rebuilt and discarded a suffix index per require). It is measured at 8000 and 32000 files at HEAP_PAD depth rather than at the timing arms' sizes, because the finding is an ABSOLUTE footprint at repository scale. THE ARM NOW READS WHAT THE LANGUAGE READS, and that change is the whole reason this file was re-baselined. Four of these arms used to call getWorkspaceFileIndex(set) directly and then read index.all.length, which asks no suffix question at all \u2014 harmless only while buildSuffixIndex built both maps eagerly. The moment they went lazy the direct call built NO map, csharp, ruby, php and java each reported 0 B at 32000 files, and 0 B is under every ceiling: --check printed PASS over four gates that had silently become ceilings over nothing, which is precisely the failure this file's own header warns about for rust and cobol. Every arm now resolves a real MISSING import through the real resolver (HEAP_PROBE_TARGET, asserted to miss), so the maps it forces are the maps production forces, and a resolver that starts asking a new question moves the number without anyone editing the bench. That makes the READ PATTERN the dominant term, and the eight numbers say so: java 34958600 B and csharp 29862200 B ask index.get and never getInsensitive; php 37579888 B asks getInsensitive and never get, plus its own first-proper-suffix map; ruby 41025360 B and javascript 26745296 B read get(s) || getInsensitive(s) and pay for both, the second DERIVED from the first; and csharp_csproj 73705944 B additionally asks getFilesInDir. csharp_csproj IS NOW GATED, reversing the earlier decision that it would be 'a ceiling on a duplicate': at +20.8% of the C# index it was one, and at 2.47x of it \u2014 same corpus, same getWorkspaceFileIndex, three maps instead of one \u2014 it is the witness that the read pattern is the footprint. The old RESIDUAL note is superseded by that number: a dirMap-sized addition is no longer +18%, and a consumer that asks all three questions blows csharp's ceiling by 1.64x rather than sliding under it. A SECOND MEASUREMENT BIAS was removed at the same time and it moved every figure here, so do not read these against the old ones as if only the read pattern changed. buildFiles mints paths with template literals, which V8 keeps as ropes; the first traversal that slices one flattens it, allocating the flat string and dropping the rope's pieces, so a build measured over an unflattened corpus reports the index MINUS that net release \u2014 11% low, uniformly. bytes_small was read over a corpus a discarded warm-up pass had already flattened and bytes_large over a fresh one, so every ratio read ~0.85-0.89 for structures that are exactly linear in the file count. measureHeap now flattens each corpus before measuring it; all eight ratios read 0.998-1.017, and the warm-up pass is gone because with the corpus flat a language's first and second reads agree to within 0.3%. python's figure rises from 7624992 to 10362976 for this reason and not because anything regressed, and then to 10543152 (+1.7%) because #2913's nestedDirNames set is retained for the pass, and then FALLS to 6360936 (-39.7%) for a reason worth knowing: byBasename holds roughly one bucket per file, and building each with `[]` followed by `push` made V8 grow the backing store to its 16-slot minimum, so every single-file bucket retained 15 empty pointer slots. Constructing the one-element buckets directly (`set(base, [entry])`) is byte-identical in contents and 3.9 MiB smaller at 32000 paths — 37% of what this arm used to read was empty array slots — the ancestorsByDir memo itself is NOT in this reading, because python's probe target misses at the nested-name rejection and never reaches the walk, so this arm does not bound that memo; measured separately with a probe that does reach it, a 32000-file corpus with every file in its own 10-deep directory retains ~19 MB, which would clear this ceiling, so repointing python's heap probe at a walking spelling means re-recording the ceiling in the same change, and c is unchanged at 10018816 because its basename map does not slice paths. Its ceiling is 1.5x the measured arm, and the DIFFERENCE FROM THE 4x TIMING CONVENTION IS DELIBERATE \u2014 do not harmonise it back. 4x exists because runner contention dominates a wall-clock number; this one has essentially no measurement noise (across 4 runs the widest spread was 0.11% on python, 0.03% on csharp_csproj and 0.00% \u2014 identical to the byte \u2014 on ruby, php, java, javascript and c, and the same holds across separate processes), so 4x would throw away almost all of the gate's power and sail straight past the regression this arm exists to catch. 1.5x still tolerates ~50% of cross-platform and Node-version drift, far more than a Node major bump plausibly moves heapUsed accounting; it catches a duplicated index (+100%) or a second exactMap-sized suffix map (+~85%). heap_floor_fraction is the arm the 0 B incident proved was missing. A ceiling can only say 'not too big'; nothing said 'still measuring something', which is why four dead arms passed. The floor is 0.5 x each language's RECORDED READING (heap_reading_bytes), which is half the measured size and says so. It used to be 0.33 x the CEILING, described the same way \u2014 true only while every ceiling stayed at exactly 1.5x its reading, a convention this file states and nothing enforces, so re-tuning one ceiling upward would have loosened that language's floor by the same factor in the one direction a floor exists to watch. The two forms agree to within 0.8% for all eight today, so this is a correction of derivation, not of strength. It sits ~400x above the readings' own reproducibility and far below any collapse. A genuine 2x memory WIN trips it too, and that is intended: like a fingerprint move, it must be explained and re-baselined rather than absorbed. COBOL is left out for the opposite reason: its index is two Map<basename, path>, O(files) with no depth term, and at 32000 files its retained delta does not clear the noise of the measurement itself. heap_ratio_budget, the linear-growth check across the 4x file-count gap, is the orthogonal arm: it sees per-file and per-depth growth but not a constant factor. ---- THE EIGHT LANGUAGES ADDED LAST (swift, rust, python, javascript, typescript, vue, c, cpp) ---- They carry the SAME five arms and the same gates; what differs is which arm can actually fail for each, because each resolver has a different cost axis, and the budgets below say so instead of copying a number across. Every figure quoted is the MAXIMUM over 5 full runs on an idle box, and the peak-to-peak of every one of these arms stayed inside 1.10x over those runs \u2014 tighter than the 1.13-1.26x the original nine record, because none of these arms divides two sub-1 ms numbers the way dart depth_ratio does. depth_budget is ~1.5x measured throughout: swift 2.3 (1.487), rust 2.1 (1.377), javascript 2.1 (1.376), typescript 2.1 (1.381), vue 2.3 (1.563), c 3.0 (1.990), cpp 3.0 (1.999). PYTHON WAS 11 AGAINST 7.389 AND IS NOW 2.6 AGAINST 1.872, because #2913 fixed the resolver rather than the budget. Its INDEX was always depth-free; hasRepoCandidate and resolveAbsoluteFromFiles each rebuilt one ancestor prefix per directory component of the importer on EVERY import, and the index's own dirPrefixes build inserted one entry per component per file, so the resolver was quadratic in path depth where every other language here is linear or flat. The prefixes are a pure function of the importer's DIRECTORY, so they are now memoized per directory inside getPythonFileIndex (ancestorsByDir), the leading segment is rejected up front against a set of nested directory names, the module and package buckets are consulted before the walk rather than inside it, and the dirPrefixes build stops at the first ancestor already stored. All five fingerprints are byte-identical, so it is a hoist. The budget is 2.2, and BOTH numbers behind it were re-measured on a quiet box AFTER the context leg below started being measured, because that change moved the arm: the work it adds is depth-FLAT, so python's absolute cost more than doubled while depth_ratio FELL to 1.405-1.563 over 5 serial runs (peak-to-peak 1.11x). A budget carried over from before that change would have been slack against a smaller ratio. 2.2 is 1.41x the measured maximum, inside the 1.37-1.75x band the other fifteen sit in, and it LOCKS THE WIN IN: reverting the per-directory ancestor memo alone scores 2.524 and reverting the nested-name rejection alone scores 2.553, both measured under the current call shape, so each fails at 2.2 with 13% to spare. Do not read those two figures as the pre-#2913 cost — 7.239 was that, and the gap closed because the bare-import tier stopped walking at all (see below). The other two parts of the fix are not gated by this arm and are not meant to be: reverting the bucket prune or the dirPrefixes early break lands under any budget this arm's noise supports, so they are gated deterministically instead, by the prefix-parity and package-probe arms of test/unit/scope-resolution/python/python-importer-ancestors.test.ts and python-import-target-parity.test.ts, which go red on exactly those two mutations. A timing budget catches what it can measure; the counts catch the rest. THE BARE-IMPORT TIER (`import os`, single segment, no dot) was a separate O(depth) walk in import-resolvers/python.ts that this bench cannot see at all, because every python arm here spells its imports with a dot and returns at the `pathLike.includes('/')` guard before reaching it. It ran TWICE per `from x import y` — the package probe's recursion re-ran the whole tail on identical inputs — and is now one memoized chain plus an O(1) proof-of-absence against the index's basename buckets: 12/24/72 Set probes at depth 1/4/16 became a flat 2, and 11.615 us/import at 18 path components became 0.740. Gated by probe COUNT in test/unit/scope-resolution/python/python-import-probe-count.test.ts, not here. collide_scaling_budget splits three ways. Three languages scan a bucket that grows with the corpus and get their measured value x1.5: swift 4.9 (3.279 \u2014 its bucket is the module file list it RETURNS, and its collide arm is four modules instead of dirs of them so that bucket is fileCount/4, i.e. 100 files at 400 and 400 at 1600), c 3.8 (2.535) and cpp 4.0 (2.639, the same basename bucket its suffix fallback walks). Four answer from keyed maps and keep the linear 1.8 \u2014 python 1.097, javascript 1.083, typescript 1.053, vue 1.079 \u2014 and that immunity IS the assertion, exactly as for ruby, kotlin, php and cobol. RUST IS THE ONE ARM THAT WAS REDESIGNED RATHER THAN BUDGETED. It resolves by probing candidate paths with allFilePaths.has(...) and never searches, so its cost is O(path segments) and provably flat in the file count (1.095 scaling, 1.061 collide scaling): a shared-leaf collide arm for rust would have asserted nothing, which is worse than no arm. Its collide corpus is instead a deep module tree (src/l0/l1/l2/l3/l4/mod{d}) whose targets carry ~2x the :: segments, so the arm exercises the axis that CAN grow, its 1.8 budget asserts the flatness across file counts, and collide_ms_ceiling 19 bounds the absolute cost of the long-path probe. small_ms_ceiling and collide_ms_ceiling are ~4x measured as everywhere else: rust 10/19 (2.609/4.704), python 7/8 (1.76/1.929, retightened from 12/15 against 3.044/3.771 by #2913), javascript 85/89 (21.254/22.145), typescript 85/86 (21.250/21.464), vue 81/93 (20.164/23.227), c 7/11 (1.620/2.850), cpp 7/12 (1.581/3.009). Swift takes ~5x (2 against 0.421 and 4 against 0.821) \u2014 the multiplier dart and cobol already carry, because a fixed scheduler hiccup is a larger fraction of a sub-1 ms number. ONE CAVEAT ON THE THREE ts-FAMILY MS NUMBERS, stated because nothing else in this file would reveal it: resolveTsTarget carries a per-pass resolveCache keyed currentFile::importPath, which no other resolver here has, and ~10% of this corpus is repeat pairs. Their us/import is therefore a slight underestimate of a cold resolve. It is left in rather than defeated because it is what the real pipeline does, and it is identical across all three so the arms stay comparable. HEAP for the eight: rust, swift, typescript, vue, cpp and cobol are still NOT gated, all of them measured before being left out. rust builds no index on this hook (16 B at 8000 files, 0 B at 32000); swift holds one pointer per file-times-segment and mints no strings, reading 0.98 MB at 8000 files against 0.29 MB at 32000 \u2014 a 4x larger corpus reading 3x SMALLER, which is what a measurement below its own noise floor looks like, and the same reading cobol gives (0.54 MB then 0 B); typescript and vue duplicate javascript through the same builder over the same-shaped corpus, and cpp duplicates c (10021320 against 10016960, 0.04% apart). Those four duplications are the ONLY exclusions that still rest on 'it would be a duplicate', and they are duplicates of a builder AND of a read pattern, which is the pairing csharp_csproj failed once the read pattern started to matter \u2014 if any of the four ever diverges in what it ASKS the index, it earns an arm the same way csharp_csproj just did. All eight gated arms are read the same way now (retainedPassBytes, one real import), so unlike before they are directly comparable to one another. WALL CLOCK \u2014 ~33-35 s in report mode, down from ~46 s, and ~44-45 s for --check, which is essentially UNCHANGED from ~46 s. Only report mode got faster; do not read the pair as 46 -> 42. The breakdown is worth having before anyone trims it. Timing arms: go 2.02, csharp 1.09, csharp_csproj 3.22, dart 0.41, ruby 2.90, kotlin 0.85, php 3.46, java 1.57, cobol 0.09, swift 0.46, rust 0.85, python 1.22, javascript 3.23, typescript 2.72, vue 2.89, c 0.86, cpp 0.91 (28.7 s, from 39.8 s: repsFor() accounts for all of it, and every second of it comes from the six languages whose cheapest cell is 20-28 ms); heap arms 3.43 s for SEVENTEEN languages, from 2.06 s for eight (every registered language is measured now; the nine added cost 1.37 s, of which kotlin alone is 0.57 s \u2014 see _heap_bound_note), and 2.1 s came from 3.0 s for seven when flattening retired the warm-up pass; module load 3.9 s. --check pays one import that report mode does not: the inventory arm loads pipeline/registry.ts, which drags in every registered scope resolver and its providers. Measured in isolation with the bench's own static imports already resident, that import costs 6.3-6.5 s on one box and 9.3-10.0 s on another \u2014 i.e. it consumes almost the whole repsFor win, which is why --check did not get faster. It is loaded dynamically at the point of use rather than at the top of the file, so report mode does not pay it and both modes take their measurements in the same module state. IT WAS WEIGHED AND KEPT, on the number that decides it: the benchmarks job is not CI's critical path. On the last green run of main it took 9 m 23 s against 12 m 58 s for the sharded coverage job that gates the merge, so ~4 m 40 s of slack sits above this bench and those seconds buy zero merge latency. Moving the arm to a vitest file would move the registry load ONTO the critical path, and would weaken it as well: this reconciles LANG_REGISTRY's SupportedLanguages values, which are what the five dispatcher branches key off, whereas a test that cannot import measure.mjs can only reconcile this file's arm NAMES plus a hand-written rule for de-aliasing csharp_csproj. The contract test import-target-index-reuse.contract.test.ts already covers the ADAPTER-boundary contract for every registered resolver; this arm covers a different claim, that the BENCH covers the pipeline. The ts family is still the largest single block of the timing phase (8.8 s) \u2014 its cost is suffixResolve probing ~39 extensions per path part on a miss, which is the real resolver and cannot be tuned away from the bench side. IF IT HAS TO SHRINK, drop collide and collide_large for typescript and vue and nothing else: -3.9 s, and it is the only cut that removes near-duplicate work rather than coverage, because all three run the same resolveTsTarget over the same buildSuffixIndex and javascript keeps the collide arm that covers their shared collision axis. Do NOT reach for REPS_MAX: it is 15 because depth_ratio tripped its own budget about 1 run in 20 at 5 and once at 7, and lowering it would re-open that for the eleven languages whose cheapest cell is sub-5 ms \u2014 which is where every recorded trip happened. The six languages it was safe to lower have already been lowered, per language and from a measurement, by repsFor(). ---- THE FIFTH ARGUMENT (context) AND THE TWO ARMS IT MOVED ---- resolveOne now makes run.ts's five-argument call for the two hooks that declare a fifth parameter, so php and python time the legs behind it. Nothing else moved: the other fifteen arms are handed no context and build no ParsedFile[] at all, and over five runs their five ms numbers and four ratios sit exactly where they did. Both languages' ten fingerprints, resolved counts and distinct_outcomes are IDENTICAL \u2014 the leg AGREES with the cascade on this corpus, which is the whole reason the context arm had to be added rather than leaving the fingerprint to notice. PHP: small_ms 27.762 -> 35.125 (+26.5%) and collide_ms 29.407 -> 36.182 (+23.0%), which is filesByDirectory plus, on every import that resolves, a candidate gather over the resolved file's directory and a localDefs filter; the ms ceilings keep PHP's own 4.21x and 4.26x multipliers (117 -> 148, 125 -> 154). depth_ratio 1.144 -> 1.283 and the 1.9 budget is UNCHANGED, which makes it 1.48x measured rather than 1.66x: directoryAliases emits one entry per path segment, so filesByDirectory is O(files x depth) and the depth arm is the only one that can see it \u2014 that budget got TIGHTER relative to its measurement, not looser, and 1.48x sits inside the 1.37-1.75x band the other sixteen carry. Its heap reading rises 37576816 -> 49574008 (+31.9%) for the same structure, and the reading is the MEMO rather than the workspace it indexes: newPass allocates the ParsedFile objects before retainedPassBytes takes its baseline sample, so they sit outside the delta. PYTHON, WHOSE FIGURES ARE THE LEAST SETTLED THING IN THIS FILE AND ARE RECORDED IN TWO SNAPSHOTS BECAUSE OF IT. A named import is the only spelling that reads context.parsedFiles, and it costs up to three entries into the resolver per import (package probe, exports check, submodule probe) where the synthetic namespace spelling this arm used to pass costs one. Against the resolver as it stood when the call shape changed that read small_ms 1.76 -> 5.751 and collide_ms 1.929 -> 5.894, ~3.1x. Against the resolver a few commits later \u2014 which stopped re-running the whole tail after a null package probe, a double-probe this bench could not previously see because the namespace spelling never entered that branch \u2014 the same arms read 4.404 and 4.505. The ceilings are 18 and 19, chosen to clear BOTH: 4.09x and 4.22x of the current numbers, 3.13x and 3.22x of the higher ones, so neither state is red. Retighten toward 4x once that resolver settles. ITS DEPTH ARM WAS DILUTED AND THE BUDGET IS RETIGHTENED TO MATCH, which is the one thing here worth arguing about: the added work is depth-FLAT, so depth_ratio FALLS 1.872 -> 1.478 while the absolute cost more than doubles, and 2.6 against 1.478 would be 1.76x \u2014 far looser than the 1.39x #2913 chose deliberately to lock its own fix in. 2.1 restores that multiplier (1.42x). THE TWO MUTATION SCORES #2913 RECORDED (3.123 for reverting the per-directory memo, 2.734 for reverting the nested-name rejection) WERE TAKEN AGAINST THE OLD CALL SHAPE AND HAVE NOT BEEN RE-TAKEN. Modelled forward, with the depth-quadratic term reappearing in every resolver entry so its absolute contribution scales with the entry count, they land near 2.8 and 2.4 \u2014 both above 2.1, and the second BELOW 2.6, which is the arithmetic that decided the budget. Re-run the two mutations before trusting the lock-in claim above. python's heap reading is unchanged (10543152 recorded; 10529848-10544616 across eight runs) because its probe misses before the branch that reads parsedFiles \u2014 see _blind_spot for why no probe can reach that memo. Every figure in this section is the MAXIMUM over its snapshot's runs (five, then three), with peak-to-peak 1.031-1.058 on php and 1.019-1.081 on python, taken on a box that was NOT idle and with another change landing in python's resolver mid-measurement. Re-take them serially before merging.",
+  "_arms_note": "Five timing arms, one memory arm and one deterministic arm elsewhere, because none of them gates alone. scaling_ratio (t_large/t_small)/(1600/400) catches cost growing with FILE COUNT \u2014 the #2877-#2880, #2901, #2902 and #2908 regressions themselves; every one of those legs was Theta(files) per import, so a revert scores ~4 here by construction. depth_ratio (t_deep/t_small at a FIXED file count, ~6x the path components) catches cost growing with path DEPTH, which scaling_ratio divides out and structurally cannot see; buildSuffixIndex (C#, Ruby, PHP, Java) and Kotlin suffixByStem emit one entry per component, so they legitimately sit above 1.0 while Go, Dart and COBOL, whose indexes are depth-free, sit at ~1.0. csharp's depth_budget has now been retightened twice for the same reason, and the second time it did lock the win in. It was 5 against a then-measured 3.318; #2903 made buildSuffixIndex's dirMap lazy and it became 3.5 against 2.31, with the file stating plainly that 3.5 did NOT lock that win in because a revert to an eager dirMap scores 3.318 and passes. Extending the laziness to the two SUFFIX maps drops it again, to 1.438 (java likewise 2.214 -> 1.402), because the deep arm has ~6x the path components and an O(files x depth) build of a map the no-csproj leg never reads is exactly the cost that scales with depth. Both are now 2.2, which is this file's 1.5x convention against measurements whose own peak-to-peak over 4 runs is 1.04x and 1.07x \u2014 and 2.2 DOES lock it in: an eager rebuild scores 2.3+ and fails. The other fifteen depth budgets sit at 1.37-1.75x measured and are unchanged. collide_scaling_ratio is the same measurement on a SHARED-LEAF layout (svcN/internal, SrcN/Models, com/example/model in every service, a repeated mod0.dart/mod0.rb/Mod0.cpy basename) carrying an identical file, import and resolved count: the small/large/deep arms mint one directory name per index, so every index bucket in them holds exactly ONE entry (measured: max last-segment bucket 1 and max matching directories 1 for go and csharp at 400 and 1600 files; max basename bucket 1 for dart and ruby), and bucket cardinality is the only non-constant term the new indexes have. On the shared-leaf shape go, csharp, dart and java legitimately score 2.1-3.9 because the bucket grows with the file count BY CONSTRUCTION \u2014 this is a limit on the SCOPE of the \"independent of corpus size\" claim, not a regression (the indexed code is still faster there than the pre-change full scan); their collide budgets say so honestly instead of pretending 1.8. Ruby, Kotlin, PHP and COBOL answer from keyed maps and are collision-immune, so they keep the linear 1.8 budget and that immunity is the assertion. csharp_csproj is the one arm that runs the other way: its shared leaf collapses dirsByLastSegment to the single key Models, so the slash-free sweep (see CSPROJ_CONFIGS) is CHEAPER on the collide layout than on the unique one and its expensive scale arm is large, not collide_large. Its 1.8 collide budget is therefore the linear one, and the arm that carries its real cost is the unique one. The collide arm is also the only arm that reaches filesDirectlyInPkgDir's dirCount > 1 merge (go: 388 multi-directory calls at 400 files, up to 9 directories; 1517 at 1600 files, up to 34) and the only one that reaches COBOL's copybook-over-source tier tie-break, which needs one bookname to name two files. small_ms_ceiling and collide_ms_ceiling are ABSOLUTE (~4x the measured arm), because a constant-factor regression that grows both scale arms equally passes every ratio. The five arms added here use 4.2x, the middle of the 3.7-4.6x the original five already carry; the two COBOL arms use ~5x, the multiplier dart's sub-1 ms arm has always carried, because a fixed scheduler hiccup is a larger fraction of a smaller number \u2014 measured over 8 runs they sat at 0.25-0.37 ms and 0.18-0.30 ms, and the pre-#2908 two-scans-per-COPY implementation costs ~300 ms on the same arm, so 2.0 and 1.5 still separate fixed from broken by two orders of magnitude. NOISE, measured rather than assumed: depth_ratio divides two sub-3 ms numbers (Dart's are sub-1 ms) and is by far the noisiest arm here, so it set N for the whole file. fastest() is a min-of-N estimator, so N is the knob. Over 22 --check runs on an idle box, peak-to-peak: at N=5 go ran 0.757-1.748 (2.31x) and tripped its own 1.6 budget about 1 run in 20; at N=7 (the kotlin-import-target setting) Dart still ran 0.678-2.043 (3.01x) and tripped once; at N=15 (bench/cfg, bench/schema-pairs, bench/callable-value-flow) every language collapsed to a 1.13-1.26x swing with 22/22 passing. The budgets were NOT widened; the estimator was fixed instead, which is why the headroom above is real rather than granted. N IS NOW PER LANGUAGE, and that is a refinement of the same finding rather than a retreat from it. The overshoot of min-of-K against min-of-15 is a function of the CELL's absolute duration, not of the language: replayed against two independent runs' full sample sets, the worst overshoots at K=7 land on swift.small (0.43 ms, 31.8%) and dart.collide (1.5 ms, 37.6%), while every cell at or above 10 ms overshoots by at most 6.3%. So repsFor() keeps 15 while a language's cheapest arm is under 5 ms and otherwise spends ~150 ms per cell, floored at 7 \u2014 15 for go, csharp, dart, kotlin, java, cobol, swift, rust, python, c and cpp (every language the flakiness above was ever about, cheapest arm 0.19-3.2 ms) and 7-8 for csharp_csproj, ruby, php, javascript, typescript and vue (cheapest arm 20-28 ms). Per LANGUAGE, not per cell, so all five arms of a language share one estimator and the four ratios stay comparisons of like with like. The replay passed all 85 cells on all five gates at 0.4-0.7 of budget and saved 12.8 s and 12.4 s of a 46 s run; min-of-7 also reads slightly HIGHER than min-of-15, so the ceilings get marginally more sensitive rather than less. Confirmed on 4 fresh runs with the adaptive estimator live: every small arm inside 1.12x peak-to-peak and every collide arm inside 1.07x, with the six 7-8 rep languages at 1.008-1.071 \u2014 no worse than the 11 that kept 15. The chosen N is reported per language as `reps`. heap_ceiling_bytes bounds the retained per-pass import index, the only arm here that can see memory: buildSuffixIndex emits maps at O(files x depth), the profile package-dir-index.ts cites #2649 to avoid for itself, and csharp, ruby, php and java all retained NOTHING across imports at BASE (C#'s no-csproj leg and PHP's and Java's every leg re-scanned the raw Set; Ruby rebuilt and discarded a suffix index per require). It is measured at 8000 and 32000 files at HEAP_PAD depth rather than at the timing arms' sizes, because the finding is an ABSOLUTE footprint at repository scale. THE ARM NOW READS WHAT THE LANGUAGE READS, and that change is the whole reason this file was re-baselined. Four of these arms used to call getWorkspaceFileIndex(set) directly and then read index.all.length, which asks no suffix question at all \u2014 harmless only while buildSuffixIndex built both maps eagerly. The moment they went lazy the direct call built NO map, csharp, ruby, php and java each reported 0 B at 32000 files, and 0 B is under every ceiling: --check printed PASS over four gates that had silently become ceilings over nothing, which is precisely the failure this file's own header warns about for rust and cobol. Every arm now resolves a real MISSING import through the real resolver (HEAP_PROBE_TARGET, asserted to miss), so the maps it forces are the maps production forces, and a resolver that starts asking a new question moves the number without anyone editing the bench. That makes the READ PATTERN the dominant term, and the eight numbers say so: java 34958600 B and csharp 29862200 B ask index.get and never getInsensitive; php 37579888 B asks getInsensitive and never get, plus its own first-proper-suffix map; ruby 41025360 B and javascript 26745296 B read get(s) || getInsensitive(s) and pay for both, the second DERIVED from the first; and csharp_csproj 73705944 B additionally asks getFilesInDir. csharp_csproj IS NOW GATED, reversing the earlier decision that it would be 'a ceiling on a duplicate': at +20.8% of the C# index it was one, and at 2.47x of it \u2014 same corpus, same getWorkspaceFileIndex, three maps instead of one \u2014 it is the witness that the read pattern is the footprint. The old RESIDUAL note is superseded by that number: a dirMap-sized addition is no longer +18%, and a consumer that asks all three questions blows csharp's ceiling by 1.64x rather than sliding under it. A SECOND MEASUREMENT BIAS was removed at the same time and it moved every figure here, so do not read these against the old ones as if only the read pattern changed. buildFiles mints paths with template literals, which V8 keeps as ropes; the first traversal that slices one flattens it, allocating the flat string and dropping the rope's pieces, so a build measured over an unflattened corpus reports the index MINUS that net release \u2014 11% low, uniformly. bytes_small was read over a corpus a discarded warm-up pass had already flattened and bytes_large over a fresh one, so every ratio read ~0.85-0.89 for structures that are exactly linear in the file count. measureHeap now flattens each corpus before measuring it; all eight ratios read 0.998-1.017, and the warm-up pass is gone because with the corpus flat a language's first and second reads agree to within 0.3%. python's figure rises from 7624992 to 10362976 for this reason and not because anything regressed, and then to 10543152 (+1.7%) because #2913's nestedDirNames set is retained for the pass, and then FALLS to 6360936 (-39.7%) for a reason worth knowing: byBasename holds roughly one bucket per file, and building each with `[]` followed by `push` made V8 grow the backing store to its 16-slot minimum, so every single-file bucket retained 15 empty pointer slots. Constructing the one-element buckets directly (`set(base, [entry])`) is byte-identical in contents and 3.9 MiB smaller at 32000 paths \u2014 37% of what this arm used to read was empty array slots \u2014 the ancestorsByDir memo itself is NOT in this reading, because python's probe target misses at the nested-name rejection and never reaches the walk, so this arm does not bound that memo; measured separately with a probe that does reach it, a 32000-file corpus with every file in its own 10-deep directory retains ~19 MB, which would clear this ceiling, so repointing python's heap probe at a walking spelling means re-recording the ceiling in the same change, and c is unchanged at 10018816 because its basename map does not slice paths. Its ceiling is 1.5x the measured arm, and the DIFFERENCE FROM THE 4x TIMING CONVENTION IS DELIBERATE \u2014 do not harmonise it back. 4x exists because runner contention dominates a wall-clock number; this one has essentially no measurement noise (across 4 runs the widest spread was 0.11% on python, 0.03% on csharp_csproj and 0.00% \u2014 identical to the byte \u2014 on ruby, php, java, javascript and c, and the same holds across separate processes), so 4x would throw away almost all of the gate's power and sail straight past the regression this arm exists to catch. 1.5x still tolerates ~50% of cross-platform and Node-version drift, far more than a Node major bump plausibly moves heapUsed accounting; it catches a duplicated index (+100%) or a second exactMap-sized suffix map (+~85%). heap_floor_fraction is the arm the 0 B incident proved was missing. A ceiling can only say 'not too big'; nothing said 'still measuring something', which is why four dead arms passed. The floor is 0.5 x each language's RECORDED READING (heap_reading_bytes), which is half the measured size and says so. It used to be 0.33 x the CEILING, described the same way \u2014 true only while every ceiling stayed at exactly 1.5x its reading, a convention this file states and nothing enforces, so re-tuning one ceiling upward would have loosened that language's floor by the same factor in the one direction a floor exists to watch. The two forms agree to within 0.8% for all eight today, so this is a correction of derivation, not of strength. It sits ~400x above the readings' own reproducibility and far below any collapse. A genuine 2x memory WIN trips it too, and that is intended: like a fingerprint move, it must be explained and re-baselined rather than absorbed. COBOL is left out for the opposite reason: its index is two Map<basename, path>, O(files) with no depth term, and at 32000 files its retained delta does not clear the noise of the measurement itself. heap_ratio_budget, the linear-growth check across the 4x file-count gap, is the orthogonal arm: it sees per-file and per-depth growth but not a constant factor. ---- THE EIGHT LANGUAGES ADDED LAST (swift, rust, python, javascript, typescript, vue, c, cpp) ---- They carry the SAME five arms and the same gates; what differs is which arm can actually fail for each, because each resolver has a different cost axis, and the budgets below say so instead of copying a number across. Every figure quoted is the MAXIMUM over 5 full runs on an idle box, and the peak-to-peak of every one of these arms stayed inside 1.10x over those runs \u2014 tighter than the 1.13-1.26x the original nine record, because none of these arms divides two sub-1 ms numbers the way dart depth_ratio does. depth_budget is ~1.5x measured throughout: swift 2.3 (1.487), rust 2.1 (1.377), javascript 2.1 (1.376), typescript 2.1 (1.381), vue 2.3 (1.563), c 3.0 (1.990), cpp 3.0 (1.999). PYTHON WAS 11 AGAINST 7.389 AND IS NOW 2.6 AGAINST 1.872, because #2913 fixed the resolver rather than the budget. Its INDEX was always depth-free; hasRepoCandidate and resolveAbsoluteFromFiles each rebuilt one ancestor prefix per directory component of the importer on EVERY import, and the index's own dirPrefixes build inserted one entry per component per file, so the resolver was quadratic in path depth where every other language here is linear or flat. The prefixes are a pure function of the importer's DIRECTORY, so they are now memoized per directory inside getPythonFileIndex (ancestorsByDir), the leading segment is rejected up front against a set of nested directory names, the module and package buckets are consulted before the walk rather than inside it, and the dirPrefixes build stops at the first ancestor already stored. All five fingerprints are byte-identical, so it is a hoist. The budget is 2.2, and BOTH numbers behind it were re-measured on a quiet box AFTER the context leg below started being measured, because that change moved the arm: the work it adds is depth-FLAT, so python's absolute cost more than doubled while depth_ratio FELL to 1.405-1.563 over 5 serial runs (peak-to-peak 1.11x). A budget carried over from before that change would have been slack against a smaller ratio. 2.2 is 1.41x the measured maximum, inside the 1.37-1.75x band the other fifteen sit in, and it LOCKS THE WIN IN: reverting the per-directory ancestor memo alone scores 2.524 and reverting the nested-name rejection alone scores 2.553, both measured under the current call shape, so each fails at 2.2 with 13% to spare. Do not read those two figures as the pre-#2913 cost \u2014 7.239 was that, and the gap closed because the bare-import tier stopped walking at all (see below). The other two parts of the fix are not gated by this arm and are not meant to be: reverting the bucket prune or the dirPrefixes early break lands under any budget this arm's noise supports, so they are gated deterministically instead, by the prefix-parity and package-probe arms of test/unit/scope-resolution/python/python-importer-ancestors.test.ts and python-import-target-parity.test.ts, which go red on exactly those two mutations. A timing budget catches what it can measure; the counts catch the rest. THE BARE-IMPORT TIER (`import os`, single segment, no dot) was a separate O(depth) walk in import-resolvers/python.ts that this bench cannot see at all, because every python arm here spells its imports with a dot and returns at the `pathLike.includes('/')` guard before reaching it. It ran TWICE per `from x import y` \u2014 the package probe's recursion re-ran the whole tail on identical inputs \u2014 and is now one memoized chain plus an O(1) proof-of-absence against the index's basename buckets: 12/24/72 Set probes at depth 1/4/16 became a flat 2, and 11.615 us/import at 18 path components became 0.740. Gated by probe COUNT in test/unit/scope-resolution/python/python-import-probe-count.test.ts, not here. collide_scaling_budget splits three ways. Three languages scan a bucket that grows with the corpus and get their measured value x1.5: swift 4.9 (3.279 \u2014 its bucket is the module file list it RETURNS, and its collide arm is four modules instead of dirs of them so that bucket is fileCount/4, i.e. 100 files at 400 and 400 at 1600), c 3.8 (2.535) and cpp 4.0 (2.639, the same basename bucket its suffix fallback walks). Four answer from keyed maps and keep the linear 1.8 \u2014 python 1.097, javascript 1.083, typescript 1.053, vue 1.079 \u2014 and that immunity IS the assertion, exactly as for ruby, kotlin, php and cobol. RUST IS THE ONE ARM THAT WAS REDESIGNED RATHER THAN BUDGETED. It resolves by probing candidate paths with allFilePaths.has(...) and never searches, so its cost is O(path segments) and provably flat in the file count (1.095 scaling, 1.061 collide scaling): a shared-leaf collide arm for rust would have asserted nothing, which is worse than no arm. Its collide corpus is instead a deep module tree (src/l0/l1/l2/l3/l4/mod{d}) whose targets carry ~2x the :: segments, so the arm exercises the axis that CAN grow, its 1.8 budget asserts the flatness across file counts, and collide_ms_ceiling 19 bounds the absolute cost of the long-path probe. small_ms_ceiling and collide_ms_ceiling are ~4x measured as everywhere else: rust 10/19 (2.609/4.704), python 7/8 (1.76/1.929, retightened from 12/15 against 3.044/3.771 by #2913), javascript 85/89 (21.254/22.145), typescript 85/86 (21.250/21.464), vue 81/93 (20.164/23.227), c 7/11 (1.620/2.850), cpp 7/12 (1.581/3.009). Swift takes ~5x (2 against 0.421 and 4 against 0.821) \u2014 the multiplier dart and cobol already carry, because a fixed scheduler hiccup is a larger fraction of a sub-1 ms number. ONE CAVEAT ON THE THREE ts-FAMILY MS NUMBERS, stated because nothing else in this file would reveal it: resolveTsTarget carries a per-pass resolveCache keyed currentFile::importPath, which no other resolver here has, and ~10% of this corpus is repeat pairs. Their us/import is therefore a slight underestimate of a cold resolve. It is left in rather than defeated because it is what the real pipeline does, and it is identical across all three so the arms stay comparable. HEAP for the eight: rust, swift, typescript, vue, cpp and cobol are still NOT gated, all of them measured before being left out. rust builds no index on this hook (16 B at 8000 files, 0 B at 32000); swift holds one pointer per file-times-segment and mints no strings, reading 0.98 MB at 8000 files against 0.29 MB at 32000 \u2014 a 4x larger corpus reading 3x SMALLER, which is what a measurement below its own noise floor looks like, and the same reading cobol gives (0.54 MB then 0 B); typescript and vue duplicate javascript through the same builder over the same-shaped corpus, and cpp duplicates c (10021320 against 10016960, 0.04% apart). Those four duplications are the ONLY exclusions that still rest on 'it would be a duplicate', and they are duplicates of a builder AND of a read pattern, which is the pairing csharp_csproj failed once the read pattern started to matter \u2014 if any of the four ever diverges in what it ASKS the index, it earns an arm the same way csharp_csproj just did. All eight gated arms are read the same way now (retainedPassBytes, one real import), so unlike before they are directly comparable to one another. WALL CLOCK \u2014 ~33-35 s in report mode, down from ~46 s, and ~44-45 s for --check, which is essentially UNCHANGED from ~46 s. Only report mode got faster; do not read the pair as 46 -> 42. The breakdown is worth having before anyone trims it. Timing arms: go 2.02, csharp 1.09, csharp_csproj 3.22, dart 0.41, ruby 2.90, kotlin 0.85, php 3.46, java 1.57, cobol 0.09, swift 0.46, rust 0.85, python 1.22, javascript 3.23, typescript 2.72, vue 2.89, c 0.86, cpp 0.91 (28.7 s, from 39.8 s: repsFor() accounts for all of it, and every second of it comes from the six languages whose cheapest cell is 20-28 ms); heap arms 3.43 s for SEVENTEEN languages, from 2.06 s for eight (every registered language is measured now; the nine added cost 1.37 s, of which kotlin alone is 0.57 s \u2014 see _heap_bound_note), and 2.1 s came from 3.0 s for seven when flattening retired the warm-up pass; module load 3.9 s. --check pays one import that report mode does not: the inventory arm loads pipeline/registry.ts, which drags in every registered scope resolver and its providers. Measured in isolation with the bench's own static imports already resident, that import costs 6.3-6.5 s on one box and 9.3-10.0 s on another \u2014 i.e. it consumes almost the whole repsFor win, which is why --check did not get faster. It is loaded dynamically at the point of use rather than at the top of the file, so report mode does not pay it and both modes take their measurements in the same module state. IT WAS WEIGHED AND KEPT, on the number that decides it: the benchmarks job is not CI's critical path. On the last green run of main it took 9 m 23 s against 12 m 58 s for the sharded coverage job that gates the merge, so ~4 m 40 s of slack sits above this bench and those seconds buy zero merge latency. Moving the arm to a vitest file would move the registry load ONTO the critical path, and would weaken it as well: this reconciles LANG_REGISTRY's SupportedLanguages values, which are what the five dispatcher branches key off, whereas a test that cannot import measure.mjs can only reconcile this file's arm NAMES plus a hand-written rule for de-aliasing csharp_csproj. The contract test import-target-index-reuse.contract.test.ts already covers the ADAPTER-boundary contract for every registered resolver; this arm covers a different claim, that the BENCH covers the pipeline. The ts family is still the largest single block of the timing phase (8.8 s) \u2014 its cost is suffixResolve probing ~39 extensions per path part on a miss, which is the real resolver and cannot be tuned away from the bench side. IF IT HAS TO SHRINK, drop collide and collide_large for typescript and vue and nothing else: -3.9 s, and it is the only cut that removes near-duplicate work rather than coverage, because all three run the same resolveTsTarget over the same buildSuffixIndex and javascript keeps the collide arm that covers their shared collision axis. Do NOT reach for REPS_MAX: it is 15 because depth_ratio tripped its own budget about 1 run in 20 at 5 and once at 7, and lowering it would re-open that for the eleven languages whose cheapest cell is sub-5 ms \u2014 which is where every recorded trip happened. The six languages it was safe to lower have already been lowered, per language and from a measurement, by repsFor(). ---- THE FIFTH ARGUMENT (context) AND THE TWO ARMS IT MOVED ---- resolveOne now makes run.ts's five-argument call for the two hooks that declare a fifth parameter, so php and python time the legs behind it. Nothing else moved: the other fifteen arms are handed no context and build no ParsedFile[] at all, and over five runs their five ms numbers and four ratios sit exactly where they did. Both languages' ten fingerprints, resolved counts and distinct_outcomes are IDENTICAL \u2014 the leg AGREES with the cascade on this corpus, which is the whole reason the context arm had to be added rather than leaving the fingerprint to notice. PHP: small_ms 27.762 -> 35.125 (+26.5%) and collide_ms 29.407 -> 36.182 (+23.0%), which is filesByDirectory plus, on every import that resolves, a candidate gather over the resolved file's directory and a localDefs filter; the ms ceilings keep PHP's own 4.21x and 4.26x multipliers (117 -> 148, 125 -> 154). depth_ratio 1.144 -> 1.283 and the 1.9 budget is UNCHANGED, which makes it 1.48x measured rather than 1.66x: directoryAliases emits one entry per path segment, so filesByDirectory is O(files x depth) and the depth arm is the only one that can see it \u2014 that budget got TIGHTER relative to its measurement, not looser, and 1.48x sits inside the 1.37-1.75x band the other sixteen carry. Its heap reading rises 37576816 -> 49574008 (+31.9%) for the same structure, and the reading is the MEMO rather than the workspace it indexes: newPass allocates the ParsedFile objects before retainedPassBytes takes its baseline sample, so they sit outside the delta. PYTHON, WHOSE FIGURES ARE THE LEAST SETTLED THING IN THIS FILE AND ARE RECORDED IN TWO SNAPSHOTS BECAUSE OF IT. A named import is the only spelling that reads context.parsedFiles, and it costs up to three entries into the resolver per import (package probe, exports check, submodule probe) where the synthetic namespace spelling this arm used to pass costs one. Against the resolver as it stood when the call shape changed that read small_ms 1.76 -> 5.751 and collide_ms 1.929 -> 5.894, ~3.1x. Against the resolver a few commits later \u2014 which stopped re-running the whole tail after a null package probe, a double-probe this bench could not previously see because the namespace spelling never entered that branch \u2014 the same arms read 4.404 and 4.505. The ceilings are 18 and 19, chosen to clear BOTH: 4.09x and 4.22x of the current numbers, 3.13x and 3.22x of the higher ones, so neither state is red. Retighten toward 4x once that resolver settles. ITS DEPTH ARM WAS DILUTED AND THE BUDGET IS RETIGHTENED TO MATCH, which is the one thing here worth arguing about: the added work is depth-FLAT, so depth_ratio FALLS 1.872 -> 1.478 while the absolute cost more than doubles, and 2.6 against 1.478 would be 1.76x \u2014 far looser than the 1.39x #2913 chose deliberately to lock its own fix in. 2.1 restores that multiplier (1.42x). THE TWO MUTATION SCORES #2913 RECORDED (3.123 for reverting the per-directory memo, 2.734 for reverting the nested-name rejection) WERE TAKEN AGAINST THE OLD CALL SHAPE AND HAVE NOT BEEN RE-TAKEN. Modelled forward, with the depth-quadratic term reappearing in every resolver entry so its absolute contribution scales with the entry count, they land near 2.8 and 2.4 \u2014 both above 2.1, and the second BELOW 2.6, which is the arithmetic that decided the budget. Re-run the two mutations before trusting the lock-in claim above. python's heap reading is unchanged (10543152 recorded; 10529848-10544616 across eight runs) because its probe misses before the branch that reads parsedFiles \u2014 see _blind_spot for why no probe can reach that memo. Every figure in this section is the MAXIMUM over its snapshot's runs (five, then three), with peak-to-peak 1.031-1.058 on php and 1.019-1.081 on python, taken on a box that was NOT idle and with another change landing in python's resolver mid-measurement. Re-take them serially before merging.",
   "_triage": "Every ratio and ms ceiling here is a TIMING signal \u2014 re-run on an idle machine before investigating; runner contention dominates. depth_ratio is the noisiest of them by a wide margin (it divides two sub-3 ms numbers, and Dart's are sub-1 ms): if exactly one arm fails and it is that one, suspect the machine first. N is 15 for every language whose cheapest arm is under 5 ms, rather than this bench's original 5, specifically to hold that arm's peak-to-peak swing under 1.26x \u2014 see _arms_note for the measured distributions and for why the six languages that drop to 7-8 are the ones where cell size makes it safe \u2014 so a depth_ratio failure that REPRODUCES is a real signal, not noise. Each language's chosen N is printed as `reps`; read it before blaming the estimator. The fingerprint, shape and heap arms are the opposite: deterministic (over 4 runs the heap arm's widest spread was 0.11% on python and 0.00% on java, javascript and c), a re-run never changes them, and they must never be wished away. TWO heap failures mean the arm STOPPED MEASURING rather than that memory grew, and both are deterministic: a heap floor failure says the probe no longer forces the index it used to (this is how four arms read 0 B when buildSuffixIndex went lazy, and 0 B passes every ceiling), and a `heap probe ... resolved` throw says a probe target that must MISS now hits, so the reading is a materialized answer and the legs past it were never reached. A heap BOUND failure is deterministic in the same way and means one specific thing: a language excluded from the budgeted tier has grown a structure, or started asking its index a question it did not ask when the exclusion was recorded \u2014 never a timing signal, never a re-run, and never fixed by raising the bound without saying what grew. The context arm is deterministic too, and a failure there means one specific thing rather than a range of them: run.ts's fifth argument is not reaching that resolver from this bench, or the leg behind it stopped running. Never a timing signal, never a re-run.",
   "_floor": "Measured against the pre-change implementations on THIS corpus at 150/600 files: go 3.36, csharp 4.10, dart 3.32, ruby 3.87. The issues report 4.00 / 3.43 / 4.05 on their own corpora; those are DIFFERENT numbers from different repositories and are not reproduced here \u2014 what they and these share is that both independently land in the quadratic band, well clear of the ~1.0 a linear result gives. Note also that this floor was taken at 150/600 while the gate runs at 400/1600, so it is a lower bound on what the pre-change code would score today. Kotlin's own bench measured its pre-index floor at 3.737. The four resolvers added later were NOT re-floored on this corpus, and the reason is that they do not need to be: every one of their pre-change legs walked the whole file set per import (PHP one findIndex per path part per extension, Java one scan per stripped prefix, COBOL two full scans per COPY, C# csproj one normalizedFileList pass per import per matching config), so their scaling_ratio is ~4 by construction rather than by measurement. Their per-import costs were measured on their own issue corpora instead: PHP 96.40 ms -> 0.036 ms, Java 8.05 ms -> 0.62 ms, COBOL 3879 us -> 10.5 us, C# csproj 1103 us -> 7.6 us. The 1.8 budget sits well above the linear result and well below every one of those. The eight languages added last were NOT floored either, and for a different reason again: they are not fixes, so there is no pre-change implementation to floor against. Their scaling budgets are the global linear 1.8 and the point of the arms is to hold the current numbers (measured 1.01-1.13) rather than to separate a fix from a break. The one exception is javascript, which IS a fix and does have a floor: 6448.9 us per import at 2000 files and 25972.6 us at 8000 \u2014 4.12x the per-import cost for 4x the files, i.e. O(imports x files) \u2014 against 28.5 / 27.4 us with the index PR #2911 gave it, and 25.0 / 27.0 us for TypeScript over the identical corpus.",
   "scaling_budget": 1.8,
@@ -90,7 +90,7 @@
     "dart": 11751300,
     "cpp": 15035016,
     "csharp": 44900000,
-    "csharp_csproj": 110600000,
+    "csharp_csproj": 109674780,
     "ruby": 61600000,
     "php": 74400000,
     "java": 52500000,
@@ -98,7 +98,7 @@
     "javascript": 40200000,
     "c": 15000000
   },
-  "_heap_reading_note": "The measured bytes_large each heap_ceiling_bytes entry above is 1.5x, recorded so the FLOOR can be derived from the reading instead of from the ceiling. It used to be 0.33 x the ceiling, described as 'half the measured size' — which held only while every ceiling stayed at exactly 1.5x its reading, a convention this file states and nothing enforces, so re-tuning one ceiling upward would have loosened that language's floor by the same factor in the one direction a floor exists to watch. 0.5 x the reading is the same effective floor to within 0.8% for all eight and says what it means. These are NOT asserted for equality: they reproduce to the byte across processes on one box, but a Node major or a different platform moves heapUsed accounting, and the ceiling/floor pair is what tolerates that (+50%/-50%). Re-baseline a ceiling and re-baseline the reading with it — they are two views of one measurement.",
+  "_heap_reading_note": "The measured bytes_large each heap_ceiling_bytes entry above is 1.5x, recorded so the FLOOR can be derived from the reading instead of from the ceiling. It used to be 0.33 x the ceiling, described as 'half the measured size' \u2014 which held only while every ceiling stayed at exactly 1.5x its reading, a convention this file states and nothing enforces, so re-tuning one ceiling upward would have loosened that language's floor by the same factor in the one direction a floor exists to watch. 0.5 x the reading is the same effective floor to within 0.8% for all eight and says what it means. These are NOT asserted for equality: they reproduce to the byte across processes on one box, but a Node major or a different platform moves heapUsed accounting, and the ceiling/floor pair is what tolerates that (+50%/-50%). Re-baseline a ceiling and re-baseline the reading with it \u2014 they are two views of one measurement.",
   "heap_reading_bytes": {
     "vue": 28884016,
     "typescript": 26745296,
@@ -107,7 +107,7 @@
     "dart": 7834200,
     "cpp": 10023344,
     "csharp": 29869080,
-    "csharp_csproj": 73703384,
+    "csharp_csproj": 73116520,
     "ruby": 41020808,
     "php": 49574008,
     "java": 34958600,
@@ -115,7 +115,7 @@
     "javascript": 26745296,
     "c": 10018816
   },
-  "_heap_bound_note": "THE SECOND HEAP TIER. Every registered language is measured now; heap_bound_bytes gates the nine that are not BUDGETED above, and it gates them with one comparison and no floor. A ceiling says 'this index is not too big'. A bound says something narrower and it is the thing that was missing: 'the exclusion still holds' — this language has not grown an index since it was left out. measure.mjs's MEMORY section states the re-entry condition (if a language ever diverges in what it ASKS its index, it earns a budgeted arm) and until now nothing watched for the divergence; HEAP_LANGS was a hand-maintained list of eight whose two neighbours, LANG_REGISTRY and CONTEXT_LANGS, are both reconciled against a derived predicate in both directions. HEAP_BOUNDED is derived too — it is LANGS minus HEAP_BUDGETED — so the two tiers partition the languages and a new one cannot land outside both. WHAT RE-MEASURING FOUND, five runs each, maximum quoted, peak-to-peak in brackets. go 2998464 B [1.0021], dart 7834200 B [1.0006] and kotlin 48073096 B [1.0004] HAD NO STATED REASON AT ALL: the old prose opened 'SIX of the seventeen are deliberately NOT in HEAP_LANGS' against a list of eight of seventeen, and these three were the three nobody counted. All three retain a real per-pass structure (go's PackageDirIndex, dart's basename buckets, kotlin's suffixByStem cascade) and kotlin's 45.85 MiB is the second-largest reading in this file, above ruby's 39.12 and java's 33.34, both of which carry a full budget. swift 3449216 B [1.0024] and cobol 2320456 B [1.0000] were excluded as 'below the measurement's own noise floor' on readings of 0.29 MB and 0 B at 32000 files; they now read 3.29 MB and 2.21 MB, growing with the corpus (969120 B and 536264 B at 8000). Those old numbers were not wrong when taken — the ARM changed under them, when #2903's follow-up made every probe resolve a real import and when measureHeap began flattening its corpus — which is the whole finding: a measurement written into prose is not re-taken, and this file had already gone stale against itself, quoting javascript at 46208832 B four paragraphs after quoting it at 25.51 MiB. rust is the one exclusion that survived unchanged: 16 B at 8000 files and 16 B at 32000, identical in all five runs. typescript 26745296 B, vue 28884016 B and cpp 10023344 B are duplicates of a builder AND of a read pattern: typescript is byte-identical to javascript's 26745296 in four runs of five, cpp is +0.05% of c's 10018816, vue is +8.0% of javascript. HOW THE BOUNDS WERE CHOSEN. Eight of the nine take 1.5x their measured maximum, rounded up to the next 100000 B: go 4500000 (1.501x), dart 11800000 (1.506x), kotlin 72200000 (1.502x), cobol 3500000 (1.508x), swift 5200000 (1.508x), typescript 40200000 (1.503x), vue 43400000 (1.503x), cpp 15100000 (1.507x). 1.5x is NOT copied from the ceilings out of habit — it is the same number for a stated reason, and the reason is not noise: measured peak-to-peak on this box is at most 1.0024, so noise alone would justify 1.05x. What a bound has to survive is a RUNNER change, since heapUsed accounting moves across platforms and Node majors, and this file already fixes that allowance at 50% for exactly this measurement on exactly this arm. Using a second allowance for the same uncertainty on the same number would be two conventions, not more rigour. At 1.5x the bound catches what the re-entry condition is about — a language growing an index, which costs +85% for one more suffix map and +100% for a duplicate — and it does NOT catch a duplicate diverging by 8%. That limit is real and is stated rather than hidden: the tight form is a same-process ratio against the arm each duplicate is a duplicate OF, which is the only form immune to the drift the absolute bound has to tolerate. RUST TAKES AN ABSOLUTE BOUND INSTEAD, 1048576 B (1 MiB), because 1.5 x 16 B is 24 B and would fail on the first byte of anything — a multiplier on a reading that is already nothing is a gate that flakes rather than a gate that bites. 1 MiB is ~65000x the reading and still 2.2x below the smallest real index measured here (cobol's 2.32 MB at the same file count), so it separates 'builds nothing' from 'builds something' with room on both sides. NO FLOOR ON ANY OF THE NINE, and the reason differs by language rather than being uniform. For rust a floor would be a floor on noise. For the other eight the readings are stable enough to floor today, and for kotlin and dart — larger than budgeted arms — a floor would be worth having, since a lazily-built map going quiet is exactly how the four budgeted arms once read 0 B. Adding one is a PROMOTION to the budgeted tier, with a ceiling and a recorded reading beside it, not a line here: a floor whose companion ceiling does not exist asserts 'still measuring' against a number nothing else bounds. Recommended next, in order: kotlin, then dart, then go.",
+  "_heap_bound_note": "THE SECOND HEAP TIER. Every registered language is measured now; heap_bound_bytes gates the nine that are not BUDGETED above, and it gates them with one comparison and no floor. A ceiling says 'this index is not too big'. A bound says something narrower and it is the thing that was missing: 'the exclusion still holds' \u2014 this language has not grown an index since it was left out. measure.mjs's MEMORY section states the re-entry condition (if a language ever diverges in what it ASKS its index, it earns a budgeted arm) and until now nothing watched for the divergence; HEAP_LANGS was a hand-maintained list of eight whose two neighbours, LANG_REGISTRY and CONTEXT_LANGS, are both reconciled against a derived predicate in both directions. HEAP_BOUNDED is derived too \u2014 it is LANGS minus HEAP_BUDGETED \u2014 so the two tiers partition the languages and a new one cannot land outside both. WHAT RE-MEASURING FOUND, five runs each, maximum quoted, peak-to-peak in brackets. go 2998464 B [1.0021], dart 7834200 B [1.0006] and kotlin 48073096 B [1.0004] HAD NO STATED REASON AT ALL: the old prose opened 'SIX of the seventeen are deliberately NOT in HEAP_LANGS' against a list of eight of seventeen, and these three were the three nobody counted. All three retain a real per-pass structure (go's PackageDirIndex, dart's basename buckets, kotlin's suffixByStem cascade) and kotlin's 45.85 MiB is the second-largest reading in this file, above ruby's 39.12 and java's 33.34, both of which carry a full budget. swift 3449216 B [1.0024] and cobol 2320456 B [1.0000] were excluded as 'below the measurement's own noise floor' on readings of 0.29 MB and 0 B at 32000 files; they now read 3.29 MB and 2.21 MB, growing with the corpus (969120 B and 536264 B at 8000). Those old numbers were not wrong when taken \u2014 the ARM changed under them, when #2903's follow-up made every probe resolve a real import and when measureHeap began flattening its corpus \u2014 which is the whole finding: a measurement written into prose is not re-taken, and this file had already gone stale against itself, quoting javascript at 46208832 B four paragraphs after quoting it at 25.51 MiB. rust is the one exclusion that survived unchanged: 16 B at 8000 files and 16 B at 32000, identical in all five runs. typescript 26745296 B, vue 28884016 B and cpp 10023344 B are duplicates of a builder AND of a read pattern: typescript is byte-identical to javascript's 26745296 in four runs of five, cpp is +0.05% of c's 10018816, vue is +8.0% of javascript. HOW THE BOUNDS WERE CHOSEN. Eight of the nine take 1.5x their measured maximum, rounded up to the next 100000 B: go 4500000 (1.501x), dart 11800000 (1.506x), kotlin 72200000 (1.502x), cobol 3500000 (1.508x), swift 5200000 (1.508x), typescript 40200000 (1.503x), vue 43400000 (1.503x), cpp 15100000 (1.507x). 1.5x is NOT copied from the ceilings out of habit \u2014 it is the same number for a stated reason, and the reason is not noise: measured peak-to-peak on this box is at most 1.0024, so noise alone would justify 1.05x. What a bound has to survive is a RUNNER change, since heapUsed accounting moves across platforms and Node majors, and this file already fixes that allowance at 50% for exactly this measurement on exactly this arm. Using a second allowance for the same uncertainty on the same number would be two conventions, not more rigour. At 1.5x the bound catches what the re-entry condition is about \u2014 a language growing an index, which costs +85% for one more suffix map and +100% for a duplicate \u2014 and it does NOT catch a duplicate diverging by 8%. That limit is real and is stated rather than hidden: the tight form is a same-process ratio against the arm each duplicate is a duplicate OF, which is the only form immune to the drift the absolute bound has to tolerate. RUST TAKES AN ABSOLUTE BOUND INSTEAD, 1048576 B (1 MiB), because 1.5 x 16 B is 24 B and would fail on the first byte of anything \u2014 a multiplier on a reading that is already nothing is a gate that flakes rather than a gate that bites. 1 MiB is ~65000x the reading and still 2.2x below the smallest real index measured here (cobol's 2.32 MB at the same file count), so it separates 'builds nothing' from 'builds something' with room on both sides. NO FLOOR ON ANY OF THE NINE, and the reason differs by language rather than being uniform. For rust a floor would be a floor on noise. For the other eight the readings are stable enough to floor today, and for kotlin and dart \u2014 larger than budgeted arms \u2014 a floor would be worth having, since a lazily-built map going quiet is exactly how the four budgeted arms once read 0 B. Adding one is a PROMOTION to the budgeted tier, with a ceiling and a recorded reading beside it, not a line here: a floor whose companion ceiling does not exist asserts 'still measuring' against a number nothing else bounds. Recommended next, in order: kotlin, then dart, then go.",
   "heap_bound_bytes": {
     "cobol": 3500000,
     "swift": 5200000,
@@ -128,90 +128,90 @@
       "small": {
         "files": 400,
         "imports": 3200,
-        "resolved": 979,
+        "resolved": 1153,
         "distinct_outcomes": 2913,
-        "fingerprint": "c96c4a0adce69f7c0e40fa84f6d2920c160e8a76d594803b4c725666fdcb7edf"
+        "fingerprint": "f2ff032eb7dc4d8f37ecfc9b56d7fc846c5a78cf9a4dfd9f78f4e04588fd0a90"
       },
       "large": {
         "files": 1600,
         "imports": 12800,
-        "resolved": 4064,
+        "resolved": 4681,
         "distinct_outcomes": 11709,
-        "fingerprint": "ec4bb401b3465713ad6dedc4f9aa774e586b319f21d406fd79eaad29f4e98861"
+        "fingerprint": "19bd34ab249a95fe93843cfb3f5ab84f8215ed0eaccef30ca50298e8dcde1d87"
       },
       "deep": {
         "files": 400,
         "imports": 3200,
-        "resolved": 979,
+        "resolved": 1153,
         "distinct_outcomes": 2913,
-        "fingerprint": "f1ce3dbe9fa4d03bae9504b644e39cc3c815d99defda70aedcf09fb743575f54"
+        "fingerprint": "67f8fa6657625080e912e417047320928f23f87ecd7a3f45283ad31684752195"
       },
       "collide": {
         "files": 400,
         "imports": 3200,
-        "resolved": 979,
+        "resolved": 1153,
         "distinct_outcomes": 2868,
-        "fingerprint": "6727beda6df2251260ee89718ea7931fa7ff1e59fa9966caf4df95f7186b6257"
+        "fingerprint": "8d82320278f74c0ebf7ba3e58fd49fde13e9927956f284774cbf39c3b8ca34a8"
       },
       "collide_large": {
         "files": 1600,
         "imports": 12800,
-        "resolved": 4064,
+        "resolved": 4681,
         "distinct_outcomes": 11570,
-        "fingerprint": "6d844763547b5cad54f41cfa0c0d618b098b214cb58654375fe7d74d229bee98"
+        "fingerprint": "f9c777dc06e32edd30570a5f9316531481941d1f91930e86e2f2bc8dbdf7d6a7"
       },
-      "fingerprint": "ec4bb401b3465713ad6dedc4f9aa774e586b319f21d406fd79eaad29f4e98861",
+      "fingerprint": "19bd34ab249a95fe93843cfb3f5ab84f8215ed0eaccef30ca50298e8dcde1d87",
       "heap": {
         "files_small": 8000,
         "files_large": 32000,
-        "path_segments": 13,
+        "path_segments": 14,
         "probe": "github.com/org/repo0/pkg/util"
       },
       "_measured": {
-        "collide_ms": 5.964,
-        "collide_scaling_ratio": 3.763,
-        "depth_ratio": 1.169,
-        "scaling_ratio": 1.045,
-        "small_ms": 1.6
+        "collide_ms": 7.15,
+        "collide_scaling_ratio": 3.465,
+        "depth_ratio": 0.999,
+        "scaling_ratio": 0.985,
+        "small_ms": 1.475
       }
     },
     "csharp": {
       "small": {
         "files": 400,
         "imports": 3200,
-        "resolved": 979,
+        "resolved": 1153,
         "distinct_outcomes": 2844,
-        "fingerprint": "cd1d665d997280a3eeb52069f2a8745f85ef91042085498a9ab546ed45faf10b"
+        "fingerprint": "503dbb3c2fd97d2fa380bc7d77d11706b42878a034a92dbc9a55620f88c53c76"
       },
       "large": {
         "files": 1600,
         "imports": 12800,
-        "resolved": 4064,
+        "resolved": 4681,
         "distinct_outcomes": 11440,
-        "fingerprint": "0b46146f5213fea8c07f1f90305a14da5ce31c865c495180f3f3903ddc6b8117"
+        "fingerprint": "1145ce5736bfea02dcd948eac9e1d263d67470f661b7bafb30061887745d2bf5"
       },
       "deep": {
         "files": 400,
         "imports": 3200,
-        "resolved": 979,
+        "resolved": 1153,
         "distinct_outcomes": 2844,
-        "fingerprint": "2baee530615a03ac6342d8d330f8b40e619b46e5de40f688ca8fb8a5f8b35027"
+        "fingerprint": "36df304d03f1d0e05e4883e69d91b95728468fdc7c7147eaa357c0ad1d022fd6"
       },
       "collide": {
         "files": 400,
         "imports": 3200,
-        "resolved": 979,
+        "resolved": 1153,
         "distinct_outcomes": 2844,
-        "fingerprint": "51d8d08e5195a416a2e7d8e42daf69bf5c5e4882239732dee454bd9c8ecf935e"
+        "fingerprint": "557c92c82c8960723f0d3ce4bf13f7d661e822d98d9597fe0f5e7c6eaf988f68"
       },
       "collide_large": {
         "files": 1600,
         "imports": 12800,
-        "resolved": 4064,
+        "resolved": 4681,
         "distinct_outcomes": 11440,
-        "fingerprint": "6d3a964bdb4ae4a0c64a1e31023fb736c42643f5aeeef704d8e00c31ae12c3af"
+        "fingerprint": "dbcab955f88895058613b0fb5b9ac81504c7bdc27344e3eab6a6272a14127796"
       },
-      "fingerprint": "0b46146f5213fea8c07f1f90305a14da5ce31c865c495180f3f3903ddc6b8117",
+      "fingerprint": "1145ce5736bfea02dcd948eac9e1d263d67470f661b7bafb30061887745d2bf5",
       "heap": {
         "files_small": 8000,
         "files_large": 32000,
@@ -219,11 +219,11 @@
         "probe": "Ghost0.Deep.Missing"
       },
       "_measured": {
-        "collide_ms": 4.074,
-        "collide_scaling_ratio": 2.163,
-        "depth_ratio": 1.438,
-        "scaling_ratio": 1.094,
-        "small_ms": 2.255
+        "collide_ms": 5.167,
+        "collide_scaling_ratio": 2.265,
+        "depth_ratio": 1.279,
+        "scaling_ratio": 1.043,
+        "small_ms": 2.45
       }
     },
     "csharp_csproj": {
@@ -490,39 +490,39 @@
       "small": {
         "files": 400,
         "imports": 3200,
-        "resolved": 1100,
+        "resolved": 1153,
         "distinct_outcomes": 2868,
-        "fingerprint": "a5e3b2e63b6c06dc1ae3655193c96801f038f9a69d448e399e1865d9f2601844"
+        "fingerprint": "c66d780f4b5549e0a9596ed30eb9035dca8e8168e90371124d1cbad968205569"
       },
       "large": {
         "files": 1600,
         "imports": 12800,
-        "resolved": 4456,
+        "resolved": 4681,
         "distinct_outcomes": 11512,
-        "fingerprint": "7ffdd453170ef36aa66c3de73f45d6ffa0588850b16111a4078f10f41782ee18"
+        "fingerprint": "354cc4de030ce581982eae15d7f6c95ba8ed14b7a14a2e0e9c3b06f90efb1eee"
       },
       "deep": {
         "files": 400,
         "imports": 3200,
-        "resolved": 1100,
+        "resolved": 1153,
         "distinct_outcomes": 2868,
-        "fingerprint": "9c1589a04dfe8c70fa5aff57ebb5742eb8999b8979a8baae701da3ef993114ec"
+        "fingerprint": "de26edd2268593f35120801c8f96799786ff01976dc84f9c342e7426be0afa9a"
       },
       "collide": {
         "files": 400,
         "imports": 3200,
-        "resolved": 1100,
+        "resolved": 1153,
         "distinct_outcomes": 2868,
-        "fingerprint": "8a08bb2d5919e9739388c0c514ae0162f6a18c10577d1b7c5bad54e2320efea5"
+        "fingerprint": "260aa5fa381b853e2cb92548a5bbb684f4afe6ba513d419e2fb2bd178f00c293"
       },
       "collide_large": {
         "files": 1600,
         "imports": 12800,
-        "resolved": 4456,
+        "resolved": 4681,
         "distinct_outcomes": 11512,
-        "fingerprint": "3286317a7e5c2ae70b1c001690980f61633566a30672e949caebcbb065e8c80f"
+        "fingerprint": "a8bcf5e432dcedf82c7b23c533311b051b00a68cbbd8bb4e816fd1c8ae055f33"
       },
-      "fingerprint": "7ffdd453170ef36aa66c3de73f45d6ffa0588850b16111a4078f10f41782ee18",
+      "fingerprint": "354cc4de030ce581982eae15d7f6c95ba8ed14b7a14a2e0e9c3b06f90efb1eee",
       "heap": {
         "files_small": 8000,
         "files_large": 32000,
@@ -530,11 +530,11 @@
         "probe": "com.google.common.vendor0.Missing"
       },
       "_measured": {
-        "collide_ms": 5.434,
-        "collide_scaling_ratio": 2.365,
-        "depth_ratio": 1.402,
-        "scaling_ratio": 1.16,
-        "small_ms": 3.18
+        "collide_ms": 5.34,
+        "collide_scaling_ratio": 2.508,
+        "depth_ratio": 1.354,
+        "scaling_ratio": 1.147,
+        "small_ms": 3.317
       }
     },
     "cobol": {
diff --git a/gitnexus/bench/import-target/measure.mjs b/gitnexus/bench/import-target/measure.mjs
index adae7ca84..3722af112 100644
--- a/gitnexus/bench/import-target/measure.mjs
+++ b/gitnexus/bench/import-target/measure.mjs
@@ -726,14 +726,21 @@ function unwiredLanguage(where, lang) {
  * UNIQUE-LEAF layout: one directory name per index, so no two directories share
  * a last segment and no two files share a basename. Every index bucket holds
  * exactly one entry. A nested same-name directory in one repo slice is the
- * shape whose handling the first-`indexOf` tie-break decides (see
- * package-dir-index.ts). Kotlin no longer applies that tie-break — #2881
- * removed it there and only there — so this one corpus shape is deliberately
- * scored two different ways: the kotlin arm resolves its `d % 7` slice and the
- * go, csharp and java arms still miss on theirs.
+ * shape the first-`indexOf` tie-break used to reject (see package-dir-index.ts);
+ * #2881 removed that tie-break from every resolver that had it, so the go,
+ * csharp, java and kotlin arms all resolve their `d % 7` slice now. Each of
+ * those four languages repeats the shape at whatever granularity ITS query uses
+ * — the last segment for csharp/java/kotlin, the whole package path for go —
+ * because a repeat the query cannot even ask about leaves the arm blind.
  */
 function uniqueDir(lang, d, i) {
-  if (lang === 'go') return d % 7 === 0 ? `src/pkg${d}/internal/pkg${d}` : `src/pkg${d}`;
+  // Go's nested slice repeats the WHOLE queried path (`src/pkg{d}`), not just
+  // its last segment. `src/pkg{d}/internal/pkg{d}` repeated only `pkg{d}`, so
+  // the query `src/pkg{d}` failed on "the directory ends with the package path"
+  // and never reached the first-occurrence rule at all — Go's arms did not move
+  // when #2881 removed that rule, which would have shipped a widened bucket
+  // with no bench coverage while C# and Java were re-baselined for it.
+  if (lang === 'go') return d % 7 === 0 ? `src/pkg${d}/internal/src/pkg${d}` : `src/pkg${d}`;
   if (lang === 'csharp') return d % 7 === 0 ? `src/Ns${d}/Sub/Ns${d}` : `src/Ns${d}`;
   if (lang === 'dart') return d % 3 === 0 ? `lib/feature${d}` : `pkg/feature${d}`;
   if (lang === 'kotlin') {
@@ -784,7 +791,10 @@ function uniqueDir(lang, d, i) {
  */
 function collideDir(lang, d, i) {
   if (lang === 'go') {
-    if (d % 7 === 0) return `svc${d}/internal/sub/internal`;
+    // `…/sub/internal` repeats only the last segment, which the ends-with test
+    // answers on its own; `…/internal/sub/svc{d}/internal` is the shape the
+    // removed first-occurrence rule used to reject (see `uniqueDir`).
+    if (d % 7 === 0) return `svc${d}/internal/sub/svc${d}/internal`;
     return d % 5 === 1 ? `svc${d}/internal/shared` : `svc${d}/internal`;
   }
   if (lang === 'csharp') return d % 7 === 0 ? `Src${d}/Models/Inner/Models` : `Src${d}/Models`;
@@ -1205,11 +1215,13 @@ function collideTarget(lang, { local, r, d, j, dirs }) {
   }
   if (lang === 'csharp') {
     return local
-      ? // `Vendor` has no directory anywhere, mirroring the unique arm's
-        // nested-same-name slice, which also resolves to nothing.
-        d % 7 === 0
-        ? `App.Src${d}.Vendor`
-        : `App.Src${d}.Models`
+      ? // This used to send the `d % 7` slice to `App.Src{d}.Vendor`, a
+        // namespace with no directory anywhere, to mirror the unique arm's
+        // nested-same-name slice, which also resolved to nothing. #2881 made
+        // that slice resolve, so the mirror has to as well — otherwise this arm
+        // stops resolving as many imports as `small`, which is the invariant
+        // that makes the two timings comparable and is asserted below.
+        `App.Src${d}.Models`
       : (r >>> 3) % 2 === 0
         ? ['System', 'System.Threading.Tasks', 'System.Collections.Generic'][(r >>> 4) % 3]
         : `Ghost${(r >>> 4) % 97}.Deep.Missing`;
@@ -1289,13 +1301,13 @@ function collideTarget(lang, { local, r, d, j, dirs }) {
     // every directory now ends in, so `firstFileDirectlyInPkgDir` walks the
     // whole `model` bucket twice — at the direct match and again after the
     // first strip — before the third strip finds `model` on its own. That walk
-    // is the non-constant term this arm exists to measure. `vendor` buckets to
-    // nothing, mirroring the unique arm's nested slice, which also misses.
+    // is the non-constant term this arm exists to measure. The `d % 7` slice
+    // used to import `com.svc{d}.vendor`, which buckets to nothing, mirroring
+    // the unique arm's nested slice — which missed until #2881 and resolves
+    // now, so the mirror follows it or the same-workload invariant below breaks.
     return local
       ? (r >>> 3) % 3 === 0
-        ? d % 7 === 0
-          ? `com.svc${d}.vendor.*`
-          : `com.svc${d}.model.*`
+        ? `com.svc${d}.model.*`
         : `com.example.model.File${j}`
       : (r >>> 3) % 2 === 0
         ? ['java.util.List', 'java.io.IOException', 'java.util.concurrent.ConcurrentHashMap'][
diff --git a/gitnexus/src/core/ingestion/import-resolvers/csharp.ts b/gitnexus/src/core/ingestion/import-resolvers/csharp.ts
index 9183fbb24..226e7ba26 100644
--- a/gitnexus/src/core/ingestion/import-resolvers/csharp.ts
+++ b/gitnexus/src/core/ingestion/import-resolvers/csharp.ts
@@ -25,16 +25,18 @@ import { csharpSuffixFallbackAllowed } from '../csharp-namespace-gate.js';
  * normalized directory of a `.cs` file and `dirPrefix` for the query:
  *
  *   let H = D + '/', P = dirPrefix + '/'
- *   match ⟺ H.length >= P.length && H.indexOf(P) === H.length - P.length
+ *   match ⟺ H.endsWith(P)
  *
- * Derivation, because both halves are load-bearing:
+ * Derivation:
  *  - the scan keeps a file only when nothing after the matched occurrence holds
  *    a slash, so the occurrence's trailing '/' must be the file's LAST slash —
  *    i.e. `H` ends with `P`;
- *  - it uses `indexOf`, the FIRST occurrence, so `a/Models/b/Models/x.cs` does
- *    NOT answer `Models`: the first `Models/` is found and `b/Models/x.cs`
- *    still contains a slash. Dropping that half moves edges in every repo that
- *    nests a directory name inside itself.
+ *  - it used `indexOf`, the FIRST occurrence, so `a/Models/b/Models/x.cs` did
+ *    NOT answer `Models`. That half was removed in #2881: it was an artifact of
+ *    how the pre-index scan was written, not a rule about C# namespaces, and it
+ *    dropped every repository that nests a directory name inside itself. The
+ *    same removal landed in `package-dir-index.ts` and in step 2 below, which
+ *    have to move together — see the note at step 3.
  *  - the needle ends with '/', so every occurrence of it lies wholly inside
  *    `D + '/'` and never reaches into the file name — which is what lets the
  *    whole test be evaluated on `D` alone.
@@ -179,11 +181,12 @@ function* matchingDirPositions(
   const needle = dirPrefix + '/';
   for (const dir of candidateDirs(index, dirPrefix)) {
     const haystack = dir + '/';
-    // The length guard is not redundant: for a shorter `haystack`, `indexOf`
-    // returns -1 and `haystack.length - needle.length` can also be -1, which
-    // would report a bogus match.
-    if (haystack.length < needle.length) continue;
-    if (haystack.indexOf(needle) !== haystack.length - needle.length) continue;
+    // `endsWith` subsumes the length guard the `indexOf` form needed: a shorter
+    // haystack is simply false, where `indexOf` returned -1 and
+    // `haystack.length - needle.length` could also be -1 and report a bogus
+    // match. Still deliberately UNANCHORED (no leading '/'), so `src/SubModels`
+    // keeps answering `Models` — see the derivation above.
+    if (!haystack.endsWith(needle)) continue;
     const positions = index.positionsByDir.get(dir);
     if (positions !== undefined) yield positions;
   }
@@ -286,8 +289,16 @@ export function resolveCSharpImportInternal(
       const dirFiles = index.getFilesInDir(dirPrefix, '.cs');
       for (const f of dirFiles) {
         const normalized = f.replace(/\\/g, '/');
-        // Check it's a direct child by finding the dirPrefix and ensuring no deeper slashes
-        const prefixIdx = normalized.indexOf(dirPrefix + '/');
+        // Direct child of a directory ENDING with `dirPrefix` — the same
+        // predicate as before minus "…and that occurrence is the FIRST one".
+        // An empty `dirPrefix` keeps `indexOf`: its needle is a bare '/', and
+        // step 3 answers that query from `singleSegmentDirs` ("exactly one
+        // directory deep"), which only the FIRST occurrence expresses. With
+        // `lastIndexOf` there, an empty prefix would accept every `.cs` that
+        // sits in any directory and step 2 would diverge from step 3.
+        const needle = dirPrefix + '/';
+        const prefixIdx =
+          dirPrefix === '' ? normalized.indexOf(needle) : normalized.lastIndexOf(needle);
         if (prefixIdx < 0) continue;
         const afterDir = normalized.substring(prefixIdx + dirPrefix.length + 1);
         if (!afterDir.includes('/')) {
@@ -301,7 +312,7 @@ export function resolveCSharpImportInternal(
     //
     // Not redundant with step 2, and not skippable when `index` is present:
     // `getFilesInDir` is keyed on SEGMENT suffixes of a directory, while this
-    // leg's predicate is an unanchored substring one, so it additionally
+    // leg's predicate is an unanchored ends-with one, so it additionally
     // answers `Models` with `src/SubModels/` and `src/Models` with
     // `vendor/mysrc/Models/`. It is also the only leg that answers an empty
     // `dirPrefix` — the `relative = ''` branch above (the import IS the root
diff --git a/gitnexus/src/core/ingestion/import-resolvers/go.ts b/gitnexus/src/core/ingestion/import-resolvers/go.ts
index f4ac5048a..a93371917 100644
--- a/gitnexus/src/core/ingestion/import-resolvers/go.ts
+++ b/gitnexus/src/core/ingestion/import-resolvers/go.ts
@@ -46,7 +46,10 @@ export function resolveGoPackage(
       normalized.endsWith('.go') &&
       !normalized.endsWith('_test.go')
     ) {
-      const afterPkg = normalized.substring(normalized.indexOf(pkgSuffix) + pkgSuffix.length);
+      // `lastIndexOf`, not `indexOf`: `pkgSuffix` is '/'-anchored on both sides,
+      // so the LAST occurrence is the file's own parent. `indexOf` asked for the
+      // first, which made `a/pkg/b/pkg/x.go` not a member of `pkg` (#2881).
+      const afterPkg = normalized.substring(normalized.lastIndexOf(pkgSuffix) + pkgSuffix.length);
       if (!afterPkg.includes('/')) {
         matches.push(allFileList[i]);
       }
diff --git a/gitnexus/src/core/ingestion/import-resolvers/package-dir-index.ts b/gitnexus/src/core/ingestion/import-resolvers/package-dir-index.ts
index 228844f2f..b54a33a45 100644
--- a/gitnexus/src/core/ingestion/import-resolvers/package-dir-index.ts
+++ b/gitnexus/src/core/ingestion/import-resolvers/package-dir-index.ts
@@ -12,27 +12,26 @@
  *
  *   let D = '/' + <normalized dir of the file> + '/'
  *   let P = '/' + pkgPath + '/'
+ *   match ⟺ D.endsWith(P)
+ *
+ * It used to say one more thing, and #2881 removed it:
+ *
  *   match ⟺ D.length >= P.length && D.indexOf(P) === D.length - P.length
  *
- * The right-hand side says two things at once, and BOTH are load-bearing:
- *  1. `D` ends with `P` — the file's directory ends with `pkgPath`;
- *  2. that trailing occurrence is the FIRST one — so `a/pkg/b/pkg/x.go` does
- *     NOT answer `pkg`, because the original `indexOf` found the earlier `/pkg/`
- *     and `b/pkg/x.go` still contained a slash. Dropping condition 2 looks like
- *     a cleanup and moves edges in every repository that nests a directory name
- *     inside itself (`internal/…/internal`, `Models/…/Models`).
+ * — i.e. `D` ends with `P` AND that trailing occurrence is the FIRST one, so
+ * `a/pkg/b/pkg/x.go` did NOT answer `pkg`. The second half was never a rule
+ * anyone chose. It is what the pre-index per-import scan happened to compute
+ * (it called `indexOf`, then checked that nothing after the match contained a
+ * slash), and the index was built to reproduce that scan byte for byte. It
+ * dropped exactly the repositories that nest a directory name inside itself:
+ * `internal/…/internal`, `Models/…/Models`, and the reported shape
+ * `data/src/main/kotlin/com/example/data/Repo.kt`, where `import data.helper`
+ * resolved to null. Kotlin was fixed first, in its own `dirChildren`
+ * (`languages/kotlin/import-target.ts`); this index and the C# csproj index
+ * followed, so the four resolvers agree again.
  *
- * Condition 2 is no longer universal across the codebase. Kotlin does not use
- * this index — it builds its own `dirChildren` in
- * `languages/kotlin/import-target.ts` — and #2881 removed the equivalent rule
- * there, because a root-level package whose name repeats higher in the tree
- * (`data/src/main/kotlin/com/example/data/Repo.kt` for `import data.helper`)
- * resolved to null. The languages served here (Go, Java, C#) still carry it and
- * still have that shape; fixing them means re-baselining three languages and
- * editing the verbatim pre-change scans that
- * `test/unit/scope-resolution/import-target-index-parity.test.ts` keeps as the
- * specification, which is why #2881 did not reach them. Read this comment as
- * "what these three languages do", not "what package resolution means".
+ * The length guard the `indexOf` form needed is gone with it: `endsWith` is
+ * false for a shorter `D` instead of comparing -1 to -1.
  *
  * Candidates are narrowed by the directory's LAST segment rather than by
  * indexing every directory suffix: a suffix map costs O(files × depth) entries,
@@ -135,11 +134,11 @@ function* matchingDirs(index: PackageDirIndex, pkgPath: string): Generator<reado
   const needle = `/${pkgPath}/`;
   for (const dir of dirs) {
     const haystack = `/${dir}/`;
-    // The length guard is not redundant: for a shorter `haystack`,
-    // `indexOf` returns -1 and `haystack.length - needle.length` can also be
-    // -1, which would report a bogus match.
-    if (haystack.length < needle.length) continue;
-    if (haystack.indexOf(needle) !== haystack.length - needle.length) continue;
+    // `endsWith` subsumes the length guard the `indexOf` form needed: a shorter
+    // haystack is simply false, where `indexOf` returned -1 and
+    // `haystack.length - needle.length` could also be -1 and report a bogus
+    // match.
+    if (!haystack.endsWith(needle)) continue;
     const files = index.filesByDir.get(dir);
     if (files !== undefined) yield files;
   }
diff --git a/gitnexus/src/core/ingestion/languages/java/import-target.ts b/gitnexus/src/core/ingestion/languages/java/import-target.ts
index 74ba8182b..98fc27c0c 100644
--- a/gitnexus/src/core/ingestion/languages/java/import-target.ts
+++ b/gitnexus/src/core/ingestion/languages/java/import-target.ts
@@ -42,10 +42,15 @@
  *     only a `.java` file can carry a `…/<name>.java` suffix key, so the
  *     extension filter is implied on the file/suffix legs and explicit in the
  *     directory index's `accept`.
- *  5. The directory-child leg matched on the FIRST `'/' + pathLike + '/'`
- *     occurrence, so `com/example/com/example/Deep.java` does NOT answer
- *     `com.example`. `firstFileDirectlyInPkgDir` encodes exactly that rule (see
- *     the header of `import-resolvers/package-dir-index.ts`).
+ *  5. The directory-child leg used to match on the FIRST `'/' + pathLike + '/'`
+ *     occurrence, so `com/example/com/example/Deep.java` did NOT answer
+ *     `com.example`. #2881 removed that: the rule came from how the pre-index
+ *     scan was written, not from Java, and it made a package whose name repeats
+ *     higher in the path unresolvable. `firstFileDirectlyInPkgDir` now answers
+ *     plain "the parent directory ends with `pathLike`" (see the header of
+ *     `import-resolvers/package-dir-index.ts`). This leg commits to ONE file
+ *     with no downstream filter, so widening it can change which file an
+ *     already-resolving import binds to, not only turn a null into a hit.
  */
 
 import type { ParsedImport, WorkspaceIndex } from 'gitnexus-shared';
diff --git a/gitnexus/src/core/ingestion/languages/kotlin/import-target.ts b/gitnexus/src/core/ingestion/languages/kotlin/import-target.ts
index cdb5f7721..594525ba5 100644
--- a/gitnexus/src/core/ingestion/languages/kotlin/import-target.ts
+++ b/gitnexus/src/core/ingestion/languages/kotlin/import-target.ts
@@ -219,7 +219,10 @@ const getKotlinFileIndex = perFileSet((allFilePaths: ReadonlySet<string>): Kotli
     // and the file IS a direct child of a directory named `s`.
     //
     // #2881: this loop used to carry two guards, both inherited from the
-    // pre-index per-import scan rather than from anything Kotlin requires —
+    // pre-index per-import scan rather than from anything Kotlin requires
+    // (the same generation of code put the `indexOf` half into
+    // `import-resolvers/package-dir-index.ts` and `import-resolvers/csharp.ts`,
+    // where it was removed under the same issue) —
     // `startsWith(s + '/')` skipped the bucket outright, and an `indexOf`
     // equality demanded that the parent be the FIRST `/s/` in the path. Between
     // them they dropped the bucket whenever the package name repeated higher up
diff --git a/gitnexus/test/unit/import-resolvers/csharp-csproj-parity.test.ts b/gitnexus/test/unit/import-resolvers/csharp-csproj-parity.test.ts
index 3bcc17ef1..c08b94a3c 100644
--- a/gitnexus/test/unit/import-resolvers/csharp-csproj-parity.test.ts
+++ b/gitnexus/test/unit/import-resolvers/csharp-csproj-parity.test.ts
@@ -12,7 +12,10 @@
  * That is wrong, and this file is the proof. Step 2 filters
  * `index.getFilesInDir(dirPrefix, '.cs')`, whose buckets are keyed on
  * SEGMENT-aligned directory suffixes; step 3 runs an UNANCHORED
- * `normalized.indexOf(dirPrefix + '/')`. Step 3 therefore answers strictly more:
+ * `normalized.lastIndexOf(dirPrefix + '/')` (`indexOf` before #2881, which is
+ * the first-occurrence rule that issue removed; the empty-prefix case still
+ * takes `indexOf` — see the guard in both copies). Step 3 therefore answers
+ * strictly more:
  *
  *   - `dirPrefix = 'ubModels'` matches `src/SubModels/` (character suffix of a
  *     segment, not a segment);
@@ -104,8 +107,14 @@ function legacyResolveCSharpImportInternal(
       const dirFiles = index.getFilesInDir(dirPrefix, '.cs');
       for (const f of dirFiles) {
         const normalized = f.replace(/\\/g, '/');
-        // Check it's a direct child by finding the dirPrefix and ensuring no deeper slashes
-        const prefixIdx = normalized.indexOf(dirPrefix + '/');
+        // Direct child of a directory ENDING with `dirPrefix` — since #2881,
+        // minus "…and that occurrence is the FIRST". Empty `dirPrefix` keeps
+        // `indexOf`: its needle is a bare '/', and step 3 answers that query
+        // from the one-directory-deep set, which only the first occurrence
+        // expresses.
+        const needle2 = dirPrefix + '/';
+        const prefixIdx =
+          dirPrefix === '' ? normalized.indexOf(needle2) : normalized.lastIndexOf(needle2);
         if (prefixIdx < 0) continue;
         const afterDir = normalized.substring(prefixIdx + dirPrefix.length + 1);
         if (!afterDir.includes('/')) {
@@ -121,7 +130,8 @@ function legacyResolveCSharpImportInternal(
       for (let i = 0; i < normalizedFileList.length; i++) {
         const normalized = normalizedFileList[i];
         if (!normalized.endsWith('.cs')) continue;
-        const prefixIdx = normalized.indexOf(dirTrail);
+        const prefixIdx =
+          dirPrefix === '' ? normalized.indexOf(dirTrail) : normalized.lastIndexOf(dirTrail);
         if (prefixIdx < 0) continue;
         const afterDir = normalized.substring(prefixIdx + dirTrail.length);
         if (!afterDir.includes('/')) {
@@ -189,7 +199,9 @@ function skipStep3WhenIndexed(
       const dirFiles = index.getFilesInDir(dirPrefix, '.cs');
       for (const f of dirFiles) {
         const normalized = f.replace(/\\/g, '/');
-        const prefixIdx = normalized.indexOf(dirPrefix + '/');
+        const needle2 = dirPrefix + '/';
+        const prefixIdx =
+          dirPrefix === '' ? normalized.indexOf(needle2) : normalized.lastIndexOf(needle2);
         if (prefixIdx < 0) continue;
         const afterDir = normalized.substring(prefixIdx + dirPrefix.length + 1);
         if (!afterDir.includes('/')) {
@@ -204,7 +216,8 @@ function skipStep3WhenIndexed(
     for (let i = 0; i < normalizedFileList.length; i++) {
       const normalized = normalizedFileList[i];
       if (!normalized.endsWith('.cs')) continue;
-      const prefixIdx = normalized.indexOf(dirTrail);
+      const prefixIdx =
+        dirPrefix === '' ? normalized.indexOf(dirTrail) : normalized.lastIndexOf(dirTrail);
       if (prefixIdx < 0) continue;
       const afterDir = normalized.substring(prefixIdx + dirTrail.length);
       if (!afterDir.includes('/')) {
@@ -252,8 +265,10 @@ const RAW_FILES: readonly string[] = [
   // Character suffix across a segment boundary: answers `rc/Models`.
   'vendor/mysrc/Models/Vendored.cs',
   'src/Models/Late.cs',
-  // `Models` nested inside `Models`: the FIRST `indexOf` occurrence is the
-  // outer one, whose remainder still holds a slash, so this answers nothing.
+  // `Models` nested inside `Models`. Answered nothing until #2881, because the
+  // FIRST `indexOf` occurrence was the outer one and its remainder still held a
+  // slash; the predicate now asks whether the file's DIRECTORY ends with the
+  // prefix, which the inner `Models` satisfies.
   'nest/Models/inner/Models/Ignored.cs',
   // Single-segment directory, so it answers the empty `dirPrefix`.
   'Models/TopLevel.cs',
@@ -483,9 +498,14 @@ describe('C# csproj leg — the answers only step 3 can give (#2902)', () => {
     ]);
   });
 
-  it('keeps the FIRST-occurrence tie-break: a directory nested inside a same-named one loses', () => {
-    // `nest/Models/inner/Models/Ignored.cs` is absent: `indexOf('odels/')` finds
-    // the outer `Models/`, and `inner/Models/Ignored.cs` still has a slash.
+  it('a directory nested inside a same-named one now answers too (#2881)', () => {
+    // `nest/Models/inner/Models/Ignored.cs` used to be absent: `indexOf('odels/')`
+    // found the OUTER `Models/`, and `inner/Models/Ignored.cs` still had a
+    // slash. The predicate is now "the file's directory ends with the prefix",
+    // which the inner `Models` satisfies. Note this arm queries `App.odels` —
+    // the UNANCHORED half — so it also pins that removing the first-occurrence
+    // rule did not accidentally anchor the match to a segment boundary:
+    // `src/SubModels/Widget.cs` is still here.
     expect(withIndex([{ rootNamespace: 'App', projectDir: '' }], 'App.odels')).toEqual([
       'src/Models/User.cs',
       'src/Models/Order.cs',
@@ -493,6 +513,7 @@ describe('C# csproj leg — the answers only step 3 can give (#2902)', () => {
       'other/Models/Thing.cs',
       'vendor/mysrc/Models/Vendored.cs',
       'src/Models/Late.cs',
+      'nest/Models/inner/Models/Ignored.cs',
       'Models/TopLevel.cs',
       'win\\Models\\Win.cs',
     ]);
@@ -506,15 +527,19 @@ describe('C# csproj leg — the answers only step 3 can give (#2902)', () => {
 
   it('a leading-slash dirPrefix cannot bogus-match a shorter directory', () => {
     // `dirPrefix = '/Models'` (projectDir used verbatim, since the import IS
-    // the root namespace): `'Models/'` is SHORTER than `'/Models/'`, and both
-    // `indexOf` and `haystack.length - needle.length` come out -1 without a
-    // length guard, so `Models/TopLevel.cs` would join the answer.
+    // the root namespace): `'Models/'` is SHORTER than `'/Models/'`, so
+    // `Models/TopLevel.cs` must not join the answer. The `indexOf` form needed
+    // an explicit length guard for this, because `indexOf` and
+    // `haystack.length - needle.length` both came out -1; `endsWith` is simply
+    // false on a shorter haystack, so the property now holds without one, and
+    // this case is what proves the guard's removal was safe.
     expect(withIndex([{ rootNamespace: 'App', projectDir: '/Models' }], 'App')).toEqual([
       'src/Models/User.cs',
       'src/Models/Order.cs',
       'other/Models/Thing.cs',
       'vendor/mysrc/Models/Vendored.cs',
       'src/Models/Late.cs',
+      'nest/Models/inner/Models/Ignored.cs',
       'win\\Models\\Win.cs',
     ]);
   });
diff --git a/gitnexus/test/unit/scope-resolution/import-target-index-parity.test.ts b/gitnexus/test/unit/scope-resolution/import-target-index-parity.test.ts
index d729ca314..c15f015c5 100644
--- a/gitnexus/test/unit/scope-resolution/import-target-index-parity.test.ts
+++ b/gitnexus/test/unit/scope-resolution/import-target-index-parity.test.ts
@@ -77,7 +77,10 @@ function legacyFindAllFilesInPkgDir(allFilePaths: ReadonlySet<string>, pkgPath:
     const normalized = '/' + raw.replace(/\\/g, '/');
     if (!normalized.includes(pkgDir)) continue;
     if (!normalized.endsWith('.go') || normalized.endsWith('_test.go')) continue;
-    const afterPkg = normalized.substring(normalized.indexOf(pkgDir) + pkgDir.length);
+    // `lastIndexOf` since #2881: `pkgDir` is '/'-anchored on both sides, so the
+    // LAST occurrence is the file's own parent. `indexOf` asked for the first,
+    // which made `a/pkg/b/pkg/x.go` not a member of `pkg`.
+    const afterPkg = normalized.substring(normalized.lastIndexOf(pkgDir) + pkgDir.length);
     if (!afterPkg.includes('/')) result.push(raw);
   }
   return result;
@@ -203,17 +206,19 @@ function legacyFindDirectChild(
   allFilePaths: ReadonlySet<string>,
   dirSegment: string,
 ): string | null {
-  const dirPrefix = `${dirSegment}/`;
-  const nestedDirPrefix = `/${dirPrefix}`;
+  // Since #2881 this is plain "the file's parent directory ends with
+  // `dirSegment`". The `atRoot`-then-`indexOf` pair it replaces expressed the
+  // same thing PLUS "…and that occurrence is the first", which is the half that
+  // was removed; the segment anchoring the leading '/' provided is kept by
+  // testing `'/' + dir + '/'` against `'/' + dirSegment + '/'`.
+  const needle = `/${dirSegment}/`;
   for (const raw of allFilePaths) {
     const f = raw.replace(/\\/g, '/');
     if (!f.endsWith('.cs')) continue;
-    const atRoot = f.startsWith(dirPrefix);
-    const atNested = f.includes(nestedDirPrefix);
-    if (!atRoot && !atNested) continue;
-    const idx = atRoot ? 0 : f.indexOf(nestedDirPrefix) + 1;
-    const after = f.slice(idx + dirPrefix.length);
-    if (after.length > 0 && !after.includes('/')) return raw;
+    const lastSlash = f.lastIndexOf('/');
+    if (lastSlash < 0) continue;
+    if (!`/${f.slice(0, lastSlash)}/`.endsWith(needle)) continue;
+    return raw;
   }
   return null;
 }
@@ -526,7 +531,7 @@ describe('import-target index hoist — output parity with the pre-change scans'
     },
     {
       lang: 'csharp',
-      why: 'a namespace dir nested inside itself does not answer the query',
+      why: 'a namespace dir nested inside itself DOES answer the query (#2881)',
       files: ['Models/Models/User.cs'],
       target: 'Models',
     },
@@ -570,15 +575,17 @@ describe('import-target index hoist — output parity with the pre-change scans'
     },
     {
       lang: 'go',
-      why: 'a package dir nested inside itself does not answer the query',
+      why: 'a package dir nested inside itself DOES answer the query (#2881)',
       files: ['a/pkg/b/pkg/x.go'],
       // Addressed through the MODULE leg as the single segment `pkg`, not as
-      // `a/pkg`. `a/pkg` never reached the first-occurrence branch this case is
-      // named for: `'/a/pkg/b/pkg/'.endsWith('/a/pkg/')` is already false, so
-      // the naive `endsWith` rewrite agreed with the real predicate and the
-      // case passed either way. With `pkg`, `endsWith('/pkg/')` is TRUE and only
-      // the "…and that occurrence is the FIRST" half rejects it. The module leg
-      // is required because the GOPATH cascade skips single-segment targets.
+      // `a/pkg`. `a/pkg` never reached the first-occurrence branch this case
+      // was named for: `'/a/pkg/b/pkg/'.endsWith('/a/pkg/')` is already false,
+      // so the `endsWith` form agreed with the old predicate and the case
+      // passed either way. With `pkg`, `endsWith('/pkg/')` is TRUE and ONLY the
+      // "…and that occurrence is the FIRST" half rejected it — which is exactly
+      // why this case is the one that flips, and why it is still the case that
+      // tells the two predicates apart. The module leg is required because the
+      // GOPATH cascade skips single-segment targets.
       target: 'example.com/mod/pkg',
       modulePath: 'example.com/mod',
     },
@@ -667,10 +674,11 @@ describe('import-target index hoist — output parity with the pre-change scans'
 
   it('every hand-built layout resolves to something (they pin a winner, not a null)', () => {
     // `toEqual(null) === toEqual(null)` would make the arm above pass for the
-    // wrong reason. Only the three "must NOT match" layouts may be null.
+    // wrong reason. Only the "must NOT match" layouts may be null. The two
+    // nested-inside-itself layouts left this set in #2881: they now resolve, so
+    // they are held to the same "pin a winner" bar as everything else, which is
+    // a stronger assertion than the null they used to carry.
     const mustBeNull = new Set([
-      'a namespace dir nested inside itself does not answer the query',
-      'a package dir nested inside itself does not answer the query',
       '_test.go files are a different package and never match',
       'paths are matched RAW — a backslash path is not normalized into a hit',
     ]);
@@ -713,9 +721,14 @@ describe('import-target index hoist — output parity with the pre-change scans'
         if (csharp(t, cs) !== null) hits.csharp++;
       }
     }
-    // Measured on this corpus: go 364, dart 75, ruby 259, csharp 196. Ruby and
+    // Measured on this corpus: go 366, dart 75, ruby 259, csharp 220. Ruby and
     // C# gained 40 each from the `win\dir\thing.<ext>` targets — one per repo,
-    // which is also the floor those two arms now defend.
+    // which is also the floor those two arms now defend. #2881 moved go 364 ->
+    // 366 and csharp 196 -> 220, from the corpus's `pkg/pkg`, `a/pkg/b/pkg` and
+    // `Models/Models` directories: those now answer their own name. The floors
+    // are deliberately NOT raised to lock that in — they exist to catch an arm
+    // that stopped resolving at all, and a revert of #2881 is caught precisely
+    // by the differential arms above, which compare against the real resolver.
     expect(hits.go).toBeGreaterThan(300);
     expect(hits.dart).toBeGreaterThan(60);
     expect(hits.ruby).toBeGreaterThan(220);
diff --git a/gitnexus/test/unit/scope-resolution/java-import-target-parity.test.ts b/gitnexus/test/unit/scope-resolution/java-import-target-parity.test.ts
index 739f245d7..837b7ea83 100644
--- a/gitnexus/test/unit/scope-resolution/java-import-target-parity.test.ts
+++ b/gitnexus/test/unit/scope-resolution/java-import-target-parity.test.ts
@@ -17,8 +17,11 @@
  *     — while its directory child is collected and returned only after the scan
  *     completes, so file/suffix beats directory child within one `skip` level
  *     regardless of order;
- *   - the directory-child leg takes the FIRST `'/' + pathLike + '/'` occurrence,
- *     so `com/example/com/example/Deep.java` does NOT answer `com.example`;
+ *   - the directory-child leg answers when the file's PARENT directory ends
+ *     with `pathLike`, so `com/example/com/example/Deep.java` DOES answer
+ *     `com.example`. It took the FIRST `'/' + pathLike + '/'` occurrence until
+ *     #2881, which made a package whose name repeats higher in its own path
+ *     unresolvable;
  *   - a wildcard import drops its trailing `.*` before any of that runs;
  *   - paths are compared normalized (`\` → `/`) but returned RAW.
  *
@@ -95,14 +98,13 @@ function legacyResolveJavaImportTarget(
       suffixFile = raw;
     }
     if (directoryChild === null) {
-      const atRoot = f.startsWith(dirPrefix);
-      const atNested = f.includes(suffixDirPrefix);
-      if (atRoot || atNested) {
-        const idx = atRoot ? 0 : f.indexOf(suffixDirPrefix) + 1;
-        const after = f.slice(idx + dirPrefix.length);
-        if (after.length > 0 && !after.includes('/')) {
-          directoryChild = raw;
-        }
+      // Since #2881: "the file's parent directory ends with `pathLike`". The
+      // `atRoot`/`indexOf` pair this replaces said that AND "…and that is the
+      // first occurrence". `>= 0`, not `> 0` — a repo-root file has `lastSlash`
+      // 0 for `/Top.java` shapes and the bare-wildcard case depends on it.
+      const lastSlash = f.lastIndexOf('/');
+      if (lastSlash >= 0 && `/${f.slice(0, lastSlash)}/`.endsWith(suffixDirPrefix)) {
+        directoryChild = raw;
       }
     }
   }
@@ -128,12 +130,9 @@ function legacyResolveJavaImportTarget(
       if (f === tailFile) return raw;
       if (f.endsWith(tailSuffix)) return raw;
       if (tailDirectChild === null) {
-        const atRoot = f.startsWith(tailDir);
-        const atNested = f.includes(tailSuffixDir);
-        if (atRoot || atNested) {
-          const idx = atRoot ? 0 : f.indexOf(tailSuffixDir) + 1;
-          const after = f.slice(idx + tailDir.length);
-          if (after.length > 0 && !after.includes('/')) tailDirectChild = raw;
+        const lastSlash = f.lastIndexOf('/');
+        if (lastSlash >= 0 && `/${f.slice(0, lastSlash)}/`.endsWith(tailSuffixDir)) {
+          tailDirectChild = raw;
         }
       }
     }
@@ -222,9 +221,11 @@ const HAND_CASES: readonly Case[] = [
     target: 'com.example.service.*',
   },
   {
-    // Tie-break 5: the FIRST `/com/example/` occurrence leaves `com/example/
-    // Deep.java` after it, which still contains a slash — so no match.
-    label: 'self-nested-directory-does-not-match-outer',
+    // Tie-break 5: the parent directory `com/example/com/example` ends with
+    // `com/example`, so it answers. Until #2881 the leg took the FIRST
+    // `/com/example/` occurrence, which leaves `com/example/Deep.java` after it
+    // — still containing a slash — and the import resolved to null.
+    label: 'self-nested-directory-answers-the-outer-package',
     files: ['com/example/com/example/Deep.java'],
     target: 'com.example',
   },
@@ -358,7 +359,7 @@ const HAND_EXPECTED: readonly string[] = [
   'directory-child-order-follows-insertion => com/example/service/Alpha.java',
   'wildcard-resolves-as-package-directory => com/example/service/Beta.java',
   'wildcard-exact-file-beats-directory => com/example/service.java',
-  'self-nested-directory-does-not-match-outer => null',
+  'self-nested-directory-answers-the-outer-package => com/example/com/example/Deep.java',
   'self-nested-directory-matches-full-path => com/example/com/example/Deep.java',
   'stripping-suffix-beats-earlier-directory-child => y/models/Order.java',
   'stripping-reaches-root-file => Order.java',