fix(build): wasteful go ffi tests rebuild

[LesnyRumcajs]

Summary of changes

Changes introduced in this pull request:

• don't regenerate some Go test files on every test build (effectively just bumping the mtime...)
• this reduces the test re-runs A LOT - right now each consecutive cargo nextest... takes around a minute to rebuild (most likely linking) even though NOTHING changed. With this change, consecutive cargo nextest... runs just run the tests without any hold-up.
• the fix is not super nice but the precedence is in the root already

  forest/build.rs

  Lines 37 to 44 in 9199a82

  	// the generated Go file has been committed to the git repository,
  	// uncomment to regenerate the code locally
  	// .with_regen_arg(rust2go::RegenArgs {
  	// src: "./src/f3/go_ffi.rs".into(),
  	// dst: "./f3-sidecar/ffi_gen.go".into(),
  	// without_main: true,
  	// ..Default::default()
  	// })

  and the files themselves don't change a lot (last change in 2025). I also don't expect them to change anytime soon.

Reference issue to close (if applicable)

Closes

Other information and links

Change checklist

• I have performed a self-review of my own code,
• I have made corresponding changes to the documentation. All new code adheres to the team's documentation standards,
• I have added tests that prove my fix is effective or that my feature works (if possible),
• I have made sure the CHANGELOG is up-to-date. All user-facing changes should be reflected in this document.

Outside contributions

• This pull request is based on an issue that a maintainer has accepted (see Before Opening a Pull Request).
• I have read and agree to the CONTRIBUTING document.
• I have read and agree to the AI Policy document. I understand that failure to comply with the guidelines will lead to rejection of the pull request.

Summary by CodeRabbit

• Chores
  • Updated the build configuration to prevent automatic regeneration of generated integration files.
  • Retained local regeneration instructions for developers when needed.

[coderabbitai]

Walkthrough

The interop test build script no longer regenerates ffi_gen.go automatically. It retains commented instructions for local regeneration.

Changes

Go FFI regeneration

Layer / File(s)	Summary
Build regeneration configuration interop-tests/build.rs	The active with_regen_arg configuration is replaced with commented local-regeneration instructions.

Estimated code review effort: 1 (Trivial) | ~2 minutes

Suggested reviewers: akaladarshi, eclesiomelojunior, gregthegreek, hanabi1224, sudo-shashank

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
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.
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly identifies the build change that prevents wasteful Go FFI test rebuilds.

✨ 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 fix-wasteful-rebuilds

✨ Simplify code

• Create PR with simplified code
• Commit simplified code in branch fix-wasteful-rebuilds

---

_{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 `@interop-tests/build.rs`:
- Around line 12-18: Add a CI step for the interop tests that enables the
regeneration configuration in build.rs and compares the regenerated ffi_gen.go
with the committed version, failing when they differ. Use the existing
rust2go::RegenArgs source and destination symbols, and keep normal builds
unchanged.

🪄 Autofix

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

Run ID: 73735eaa-40f3-44a0-8184-7ebba7383fd2

📥 Commits

Reviewing files that changed from the base of the PR and between 9199a82 and d1eb007.

📒 Files selected for processing (1)

• interop-tests/build.rs

🔗 Linked repositories identified

CodeRabbit considers these linked repositories for cross-repo context during reviews:

• filecoin-project/lotus (manual)

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 65.13%. Comparing base (9199a82) to head (d1eb007).
✅ All tests successful. No failed tests found.

Additional details and impacted files

see 9 files with indirect coverage changes

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