[claude] Fix FwHeadless silently dropping FieldWorks edits (chorusmerge handler discovery)

[myieye]

[Claude, autonomous]

FwHeadless silently drops FieldWorks-desktop edits when a file needs a real 3-way merge: the ChorusMerge process never finds its *-ChorusPlugin.dll handlers (the MEF scan is cwd-relative and hg runs the merge tool from the repo, not /app), so conflicts fall back to whole-file "keep ours". Background in #2508.

Two commits, landing intentionally red → green:

1. A build-time smoke-test that runs the real chorusmerge from a non-/app cwd on a split PartsOfSpeech.list, editing two different possibility items, and asserts both survive. Red on the current setup — it reproduces the data loss in CI.
2. The fix: cd into the script dir so ChorusMerge's cwd-relative handler scan lands on /app. hg passes absolute file paths to the merge tool, so changing cwd is safe. Turns the smoke-test green.

Interim shim (#2510); the durable upstream fix is tracked in #2511 / sillsdev/chorus#392.

Closes #2509, #2510.

🤖 Generated with Claude Code

[coderabbitai]

📝 Walkthrough

Walkthrough

The chorusmerge wrapper now runs from its script directory. A new PartsOfSpeech fixture and shell smoke test validate handler-based merging, and the Docker build executes that test using a bind mount.

Changes

Chorusmerge smoke validation

Layer / File(s)	Summary
Chorusmerge working-directory handling backend/FwHeadless/chorusmerge	The wrapper changes to its resolved script directory before invoking ChorusMerge.dll, failing with an error if the directory change fails.
Smoke-test fixture and merge validation backend/FwHeadless/chorusmerge-smoke/*	A PartsOfSpeech XML fixture and shell script create divergent inputs, run chorusmerge, and verify both edits appear in the merged output.
Docker build integration backend/FwHeadless/Dockerfile	The build bind-mounts the smoke-test fixture and executes its runner.

Estimated code review effort: 2 (Simple) | ~10 minutes

Possibly related issues

• #2509 — Requests the build-time chorusmerge smoke test and handler-discovery fix.
• #2508 — Describes the handler-discovery regression addressed by the working-directory change and smoke test.
• #2510 — Requests changing into the wrapper directory before launching ChorusMerge.dll.

Suggested reviewers: rmunn

Poem

I thump my paws: the merge now knows
Which directory its handler grows.
Two edits hop into the list,
The Docker build gives them a kiss.
“No silent keep-ours!” sings the hare.

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title clearly summarizes the main fix: FwHeadless was dropping FieldWorks edits due to chorusmerge handler discovery.
Description check	✅ Passed	The description directly matches the changeset and explains the smoke test plus the cwd fix.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

✨ Finishing Touches

📝 Generate docstrings

• Create stacked PR
• Commit on current branch

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch claude/fw-headless-conflict-mode-e2066c

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[coderabbitai]

Actionable comments posted: 1

🤖 Prompt for all review comments with AI agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

Inline comments:
In `@backend/FwHeadless/chorusmerge-smoke/run.sh`:
- Around line 27-29: Update the success condition following the chorusmerge
invocation to require rc to indicate a zero exit status in addition to finding
Adverb_OURS and Verb_THEIRS in merged.list. Preserve the existing content
checks, and ensure non-zero or conflicted merge results cannot report success.

🪄 Autofix (Beta)

Fix all unresolved CodeRabbit comments on this PR:

• Push a commit to this branch (recommended)
• Create a new PR with the fixes

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ℹ️ Review info

⚙️ Run configuration

Configuration used: Repository UI

Review profile: CHILL

Plan: Pro Plus

Run ID: eacfd2c4-68bb-459e-96d0-2b8bfe17c392

📥 Commits

Reviewing files that changed from the base of the PR and between a425984 and 5f59196.

📒 Files selected for processing (4)

• backend/FwHeadless/Dockerfile
• backend/FwHeadless/chorusmerge
• backend/FwHeadless/chorusmerge-smoke/PartsOfSpeech.base.list
• backend/FwHeadless/chorusmerge-smoke/run.sh