test(gc): register the dark call-argument witness from #7252

[proggeramlug]

test-files/test_gap_gc_call_argument_rooting.ts shipped with #7252 and was never added to test-parity/gc_repsel_corpus.txt. It has not run anywhere since that merge. Adding the line is the entire fix.

How it surfaced

The GC Moving Witnesses job failed on main with:

test_gap_gc_call_argument_rooting exists but was not run: register it in test-parity/gc_repsel_corpus.txt. The matrix only auto-detects the test_gap_repsel_*/test_gap_specabi_* prefixes, so a test_gap_gc_* witness that is not registered is silently dark (#6925 is the precedent).

This is the third occurrence of the same mistake. #7192 and #7216 did it before, and are documented in that file immediately above the line this PR adds. The difference is that this one was caught by a machine instead of by someone noticing months later — the test_gap_gc_* enforcement written in response to those two did its job.

It only got the chance because #7253 gave the moving-GC matrix a main-line trigger two hours earlier. Before that, gc-stress reported skipped on 12/12 nightly runs, and this witness would have stayed dark indefinitely.

I merged #7252 (restacking @jdalton's branch past two squash-merged parents), so this omission is mine to fix.

What is NOT verified

CI is the first real execution of this test. I did not build locally to run it — the box is disk-constrained. If it goes red, that is the test doing its job on first contact, and it would be the first independent exercise of the rooting fix #7252 shipped. A dark test is strictly worse than a red one.

Summary by CodeRabbit

• Bug Fixes

  • Added the missing garbage-collection test to the test corpus so it runs as intended.
  • Improved test coverage for call argument rooting scenarios.

• Documentation

  • Added a changelog entry documenting the previously omitted test and its correction.

[coderabbitai]

📝 Walkthrough

Walkthrough

The GC representation-selection corpus now registers test_gap_gc_call_argument_rooting. A changelog entry documents the prior omission, its test-execution impact, and the enforcement that detected it.

Changes

GC corpus registration

Layer / File(s)	Summary
Register and document the GC witness test-parity/gc_repsel_corpus.txt, changelog.d/7263-register-dark-call-arg-witness.md	The manifest adds test_gap_gc_call_argument_rooting with explanatory comments. The changelog records the missing registration and its detection.

Estimated code review effort: 1 (Trivial) | ~5 minutes

Possibly related PRs

• PerryTS/perry#7240: Introduced the cross-module call argument-rooting regression test registered here.
• PerryTS/perry#7252: Landed the regression test whose corpus registration this change adds.
• PerryTS/perry#7228: Introduced enforcement for omitted GC regression witnesses.

Suggested reviewers: jdalton

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Description check	⚠️ Warning	The description explains the omission and fix but does not follow the required template or include its required sections and checklist.	Use the repository template and add the Summary, Changes, Related issue, Test plan, Screenshots/output, and Checklist sections.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title clearly identifies the main change: registering the GC call-argument witness test.
Linked Issues check	✅ Passed	The PR registers the regression test required by #7252, ensuring coverage for cross-module call argument rooting is executed.
Out of Scope Changes check	✅ Passed	The changelog entry and corpus registration directly support the linked issue and contain no unrelated code changes.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch fix/register-dark-call-arg-witness

---

Thanks for using CodeRabbit! It's free for OSS, and your support helps us grow. If you like it, consider giving us a shout-out.

❤️ Share

• X
• Mastodon
• Reddit
• LinkedIn

_{Comment @coderabbitai help to get the list of available commands.}

[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 `@test-parity/gc_repsel_corpus.txt`:
- Around line 290-292: Update the comment for test_gap_gc_call_argument_rooting
to change the relative-location reference from “above” to “below,” since the
referenced sections appear later in the file.

🪄 Autofix (Beta)

Fix all unresolved CodeRabbit comments on this PR:

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

---

ℹ️ Review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro Plus

Run ID: 9dc60482-3471-40c5-b7d7-b05cb8cf5f1e

📥 Commits

Reviewing files that changed from the base of the PR and between d4ac65f and 3cde340.

📒 Files selected for processing (2)

• changelog.d/7263-register-dark-call-arg-witness.md
• test-parity/gc_repsel_corpus.txt

[coderabbitai]

📐 Maintainability & Code Quality | 🟡 Minor | ⚡ Quick win

Correct the stale relative-location reference.

Line 292 says that #7192 and #7216 are documented “above.” Their section starts at Line 299, below this block. Change “above” to “below.”

🤖 Prompt for 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.

In `@test-parity/gc_repsel_corpus.txt` around lines 290 - 292, Update the comment
for test_gap_gc_call_argument_rooting to change the relative-location reference
from “above” to “below,” since the referenced sections appear later in the file.