fix(lua): clear stale heritage on reanalysis; wire Lua prebuild workflow

Three paths flagged in review (azizur100389):

1. clearLuaHeritageFacts() had no caller, and captures.ts only set
   heritage facts when non-empty — a re-capture of a file that lost its
   middleclass class left prior EXTENDS/HAS_METHOD facts for
   collectLuaCaptureSideChannel to snapshot as stale edges. Add a per-file
   delete on empty recapture (clearLuaHeritageFactsForFile) and wire
   clearLuaHeritageFacts() into loadResolutionConfig (mirrors Java/Kotlin).

2. Lua was absent from build-tree-sitter-prebuilds.yml despite the PR
   vendoring tree-sitter-lua source-only (parser.c/scanner.c/binding.gyp)
   — toolchain-less install failed on platforms the upstream npm package
   doesn't cover. Add lua to the REGISTRY (kind 'vendored') + a parse
   snippet for the validate step; commit-fork-prebuilds.yml is generic.

3. Add a lifecycle regression: emitLuaScopeCaptures with no heritage
   after a prior heritage capture must leave collectLuaCaptureSideChannel
   undefined (verified the test fails without the per-file delete).

.github/workflows/build-tree-sitter-prebuilds.yml

@@ -7,7 +7,7 @@ name: Build tree-sitter prebuilds
 #
 # Grammars covered here (the at-risk set — everything else already ships 6
 # upstream prebuilds AND stays dependency-review-tracked, so it is left alone).
-# All five are vendored under gitnexus/vendor/; `kind` (below) only picks where
+# All six are vendored under gitnexus/vendor/; `kind` (below) only picks where
 # the build job fetches the C source to compile:
 #   - tree-sitter-c      (vendored prebuild-only; built from the published npm
 #                         package — closes upstream's 4/6 ARM gap #2116 for a
@@ -20,6 +20,9 @@ name: Build tree-sitter prebuilds
 #   - tree-sitter-swift  (vendored source; built from gitnexus/vendor/ — its
 #                         prebuilds were originally upstream-shipped, now
 #                         GitNexus-cross-built like the rest for uniformity)
+#   - tree-sitter-lua    (vendored source; built from gitnexus/vendor/ — the
+#                         upstream npm package ships source-only for the
+#                         relevant tuples, so all 6 are cross-built here)
 #
 # Output: gitnexus/vendor/<grammar>/prebuilds/<platform-arch>/<grammar>.node for
 # all 6 targets ({linux,darwin,win32}-{x64,arm64}). tree-sitter grammars are
@@ -55,7 +58,7 @@ on:
   workflow_dispatch:
     inputs:
       grammars:
-        description: 'Comma-separated grammar shortnames to build (c,dart,proto,kotlin,swift), or "all".'
+        description: 'Comma-separated grammar shortnames to build (c,dart,proto,kotlin,swift,lua), or "all".'
         required: false
         type: string
         default: 'all'
@@ -157,6 +160,11 @@ jobs:
             // so it builds from gitnexus/vendor/ like dart/proto. Its prebuilds
             // were originally upstream-shipped; rebuilding them here unifies it.
             swift:  { name: 'tree-sitter-swift',  kind: 'vendored' },
+            // lua is vendored WITH its source (parser.c/scanner.c/binding.gyp);
+            // the upstream npm package ships SOURCE ONLY for the relevant
+            // platform tuples, so GitNexus cross-builds all 6 prebuilds here
+            // like dart/proto/swift to keep install toolchain-free everywhere.
+            lua:    { name: 'tree-sitter-lua',    kind: 'vendored' },
           };
           const PLATFORMS = [
             { platform_arch: 'linux-x64',    os: 'ubuntu-24.04' },
@@ -467,6 +475,7 @@ jobs:
               proto:  "syntax = \"proto3\";\nmessage M { int32 id = 1; }",
               kotlin: "fun main() { println(\"hi\") }",
               swift:  "func greet() { print(\"hi\") }",
+              lua:    "local x = 1\nreturn x",
             };
             const lang = require("node-gyp-build")(process.cwd());
             const Parser = require("tree-sitter");

gitnexus/src/core/ingestion/languages/lua/capture-side-channel.ts

@@ -48,3 +48,10 @@ export function collectLuaCaptureSideChannel(filePath: string): LuaCaptureSideCh
 export function clearLuaHeritageFacts(): void {
   _facts.clear();
 }
+
+/** Drop this file's facts so a re-capture that produces no heritage (the file
+ *  lost its middleclass class between passes) does not leave stale EXTENDS /
+ *  HAS_METHOD facts for `collectLuaCaptureSideChannel` to snapshot. */
+export function clearLuaHeritageFactsForFile(filePath: string): void {
+  _facts.delete(filePath);
+}

gitnexus/src/core/ingestion/languages/lua/captures.ts

@@ -23,6 +23,7 @@ import { nodeToCapture } from '../../utils/ast-helpers.js';
 import { getLuaParser, getLuaScopeQuery, getHeritageQuery, getMethodOwnerQuery } from './query.js';
 import {
   setLuaHeritageFacts,
+  clearLuaHeritageFactsForFile,
   type LuaExtendsPair,
   type LuaMethodOwnerPair,
 } from './capture-side-channel.js';
@@ -95,6 +96,11 @@ export function emitLuaScopeCaptures(
   }
   if (extendsPairs.length > 0 || methodOwners.length > 0) {
     setLuaHeritageFacts(filePath, { kind: 'lua', extendsPairs, methodOwners });
+  } else {
+    // Re-capture produced no heritage — drop any prior facts for this file so
+    // reanalysis of a file that lost its middleclass class does not emit stale
+    // EXTENDS / HAS_METHOD edges from the previous pass.
+    clearLuaHeritageFactsForFile(filePath);
   }
 
   return out;

gitnexus/src/core/ingestion/languages/lua/scope-resolver.ts

@@ -18,6 +18,7 @@ import { buildSuffixIndex, suffixResolve, type SuffixIndex } from '../../import-
 import type { ScopeResolver } from '../../scope-resolution/contract/scope-resolver.js';
 import { luaProvider } from '../lua.js';
 import { emitLuaHeritageEdges } from './heritage.js';
+import { clearLuaHeritageFacts } from './capture-side-channel.js';
 
 // Cache the suffix index across calls within one analyze run — `allFilePaths`
 // is the same ReadonlySet for every Lua import in the run, so keying on its
@@ -32,6 +33,16 @@ const luaScopeResolver: ScopeResolver = {
   languageProvider: luaProvider,
   importEdgeReason: 'lua-scope: require',
 
+  // Worker capture facts are process-local and can outlive a single analysis in
+  // server mode. Runs once before each Lua workspace pass, mirroring the
+  // Java/Kotlin `loadResolutionConfig` clear. The per-file delete in
+  // `captures.ts` is the operative fix for the empty-recapture stale path;
+  // this clear-all is the belt-and-suspenders lifecycle hook.
+  loadResolutionConfig: () => {
+    clearLuaHeritageFacts();
+    return undefined;
+  },
+
   // require("a.b.c") → module path a/b/c (+ EXTENSIONS: .lua / /init.lua).
   // targetRaw arrives quote-stripped (interpretLuaImport); Lua's module
   // separator is `.`, so split on it before joining to a path.

gitnexus/test/integration/resolvers/lua-scope.test.ts

@@ -19,6 +19,8 @@ import {
   runPipelineFromRepo,
   type PipelineResult,
 } from './helpers.js';
+import { emitLuaScopeCaptures } from '../../../src/core/ingestion/languages/lua/index.js';
+import { collectLuaCaptureSideChannel } from '../../../src/core/ingestion/languages/lua/capture-side-channel.js';
 
 function writeFixtureRepo(root: string, files: Record<string, string>): void {
   for (const [rel, content] of Object.entries(files)) {
@@ -133,3 +135,45 @@ return Dog
     expect(classes).toContain('Animal');
   });
 });
+
+// ---------------------------------------------------------------------------
+// heritage lifecycle: re-capture with no middleclass must not retain stale
+// EXTENDS / HAS_METHOD facts from a prior pass (reanalysis regression)
+// ---------------------------------------------------------------------------
+
+describe('Lua scope: heritage lifecycle (no stale facts on reanalysis)', () => {
+  // The capture side channel is a module-level map populated by
+  // `emitLuaScopeCaptures` (worker) and snapshotted by
+  // `collectLuaCaptureSideChannel`. Calling both here in the test process
+  // exercises the same module instance, so a re-capture that produces no
+  // heritage must drop the prior facts — otherwise reanalysis of a file that
+  // lost its middleclass class would emit stale EXTENDS / HAS_METHOD edges.
+  const heritageSrc = `local class = require("lib.class")
+local Animal = class("Animal")
+function Animal:speak() return "..." end
+local Dog = class("Dog", Animal)
+function Dog:bark() return "woof" end
+return Dog
+`;
+  const noHeritageSrc = `local x = 1
+return x
+`;
+
+  it('populates facts on a middleclass capture', () => {
+    emitLuaScopeCaptures(heritageSrc, 'lifecycle.lua');
+    const facts = collectLuaCaptureSideChannel('lifecycle.lua');
+    expect(facts).toBeDefined();
+    expect(facts?.extendsPairs.length).toBeGreaterThan(0);
+    expect(facts?.methodOwners.length).toBeGreaterThan(0);
+  });
+
+  it('clears facts on a subsequent no-heritage capture (no stale state)', () => {
+    // First capture establishes heritage facts for the file.
+    emitLuaScopeCaptures(heritageSrc, 'lifecycle.lua');
+    expect(collectLuaCaptureSideChannel('lifecycle.lua')).toBeDefined();
+    // Re-capture with no middleclass — the prior facts must be dropped, not
+    // retained for collectLuaCaptureSideChannel to snapshot as stale edges.
+    emitLuaScopeCaptures(noHeritageSrc, 'lifecycle.lua');
+    expect(collectLuaCaptureSideChannel('lifecycle.lua')).toBeUndefined();
+  });
+});