Addresses a Copilot review comment on #653.
The source array is runtime data, usually produced by a model, so its
length is not something a workflow author reviewed. Two changes, so an
over-long array degrades into a clear error rather than memory pressure.
Cap the item count at 1000. Above that the stage fails deterministically
before `parallel.started`, alongside the other for_each contract
violations, and the message says how to reduce the array.
Fork the parent context inside the branch task, after it acquires a
`max_parallel` slot, instead of at dispatch time. Live context copies now
track `max_parallel` rather than item count. Only the branch's own
preamble entry is moved into the task, so the shared stash is not cloned
per branch either.
The reviewer also suggested replacing spawn-all with `max_parallel`
workers pulling from a queue. Not done here: with the fork deferred, a
pending task holds little beyond its item, and reshaping the dispatch
loop would change cancellation and scope-reservation ordering, which
deserves its own review.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
build_branch_plan read the runtime array before run_branches looked at
`simulated`, so every for_each workflow failed under --dry-run with
"for_each source '...' was not found in workflow context". Nothing had
populated the key yet: upstream LLM nodes take Handler::simulate, which
returns no context updates.
A dry run now stands in one placeholder item when the source is absent or
unusable, and simulates the template target once. Graph-shape mistakes
still fail, since catching those is the point of a dry run.
Also from review:
- ITEM_FENCE_PREFIX replaces the bare "untrusted-" literal that
render_item_data and its test each spelled out.
- ItemRecordingHandler no longer guesses an item label by substring
search. Nothing asserted it, and the third item's label "2" matched
stray hex from the random fence tag about two thirds of the time.
- The twin test reads keys::PARALLEL_RESULTS instead of the raw string.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Review follow-ups: the ParallelBranchResult snippet showed status as
String (it is StageOutcome), and the cancellation section implied a
cancelled branch status that the type does not have — cancelled-while-
waiting branches record a failed outcome (reason "branch cancelled")
and the handler returns Error::Cancelled to the run executor.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Cumulative implement + simplify_fable diff recovered from the run's meta
branch (fabro/meta/01KY7YH7RYCJ1BDVTTP96ZA4HV, stage 006 diff.patch).
The run validated this tree clean: cargo nextest (7,007 passed), clippy,
fmt, TS client regen + typecheck, web tests (679 passed), docs check.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
