fix(daemon): resolve test-emu project_dir against the caller's cwd (#1415)

[zackees]

Refs #1415.

build, deploy and install_deps already resolve project_dir via resolve_request_project_dir; POST /api/test-emu was the remaining handler reading the raw string against the daemon's own cwd, so a second project's test-emu within the daemon idle window ran the first project's sketch. It now uses the same resolver, and its lock/error text names the resolved absolute path.

Regression tests (tests_project_dir.rs): project_dir: "." with caller_cwd elsewhere reads the caller's platformio.ini (the daemon cwd has none); a missing relative dir reports the resolved path.

Not covered here: the monitor/reset handlers don't take a project_dir from what I found; the issue can be closed once this merges unless you know of others.

Summary by CodeRabbit

• Bug Fixes
  • Emulator test requests now resolve relative project directories using the caller’s working directory, helping the endpoint locate the intended project.
  • When a project directory is missing, the error message now identifies its resolved path.

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Reviewing files that changed from the base of the PR and between 1520b87 and 31ea47f.

📒 Files selected for processing (1)

• crates/fbuild-daemon/src/handlers/emulator/tests_project_dir.rs

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📥 Commits

Reviewing files that changed from the base of the PR and between a1b1ade and 1520b87.

📒 Files selected for processing (4)

• crates/fbuild-daemon/src/handlers/emulator/mod.rs
• crates/fbuild-daemon/src/handlers/emulator/select.rs
• crates/fbuild-daemon/src/handlers/emulator/tests_project_dir.rs
• crates/fbuild-daemon/src/handlers/operations/mod.rs

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📝 Walkthrough

Walkthrough

The emulator test handler now resolves the request’s project directory using the optional caller working directory. Its operation-guard label and missing-directory error use the resolved path. Tests cover relative and missing project directories.

Changes

Emulator project directory resolution

Layer / File(s)	Summary
Resolve project directory in emulator tests crates/fbuild-daemon/src/handlers/operations/mod.rs, crates/fbuild-daemon/src/handlers/emulator/select.rs, crates/fbuild-daemon/src/handlers/emulator/tests_project_dir.rs, crates/fbuild-daemon/src/handlers/emulator/mod.rs	The operations module re-exports resolve_request_project_dir. test_emu uses it with the request project path and optional caller working directory. The operation-guard label and missing-directory error report the resolved path. Tests cover a relative path with a bogus platform configuration and a missing relative directory. The test module is included only in test builds.

Priority: ➖ Normal

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

Change: Bug fix

Merge Risk: ⚪ Minimal · up to 1520b

No actionable issue remains; the change is ready to merge after normal checks.

Architecture Summary

Architecture risk: 🟡 Medium · up to 1520b

The change affects 1 system.

Changed systems: crates

Architecture concerns
No architecture-level concerns identified.

Review details

Systems and components

• observed — crates (service) was modified; 4 changed files map to changed impact.

Before / after behavior

• observed — Modified behavior in crates/fbuild-daemon/src/handlers/emulator/mod.rs: Adds the tests_project_dir module under #[cfg(test)], so it is included only in test builds.
• observed — Modified behavior in crates/fbuild-daemon/src/handlers/emulator/select.rs: test_emu now resolves the project directory using req.project_dir and the optional caller working directory, replacing direct PathBuf construction from the request path.
• observed — Modified behavior in crates/fbuild-daemon/src/handlers/emulator/select.rs: The operation-guard label and missing-project-directory error now report the resolved project path instead of req.project_dir.
• observed — Modified behavior in crates/fbuild-daemon/src/handlers/emulator/tests_project_dir.rs: Adds a request helper that supplies project_dir and caller_cwd, plus a test that invokes test_emu with "." and expects a failed response mentioning the bogus platform written to the caller’s platformio.ini.

Reliability and maintainability

• inferred — Risk-relevant change factors for crates: blast_radius_2; direct_dependents_2

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 75.00% which is insufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff. Analyzed 4 functions across 4 files.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly and concisely describes the main change: resolving test-emu project directories against the caller's working directory.
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.

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