test(desktop): Keep WSL busy-runtime fixtures visible when sh is bash

[mwolson]

What Changed

The executed WSL cache tests now mark a runtime busy, and hold an install lock, with helper processes that end when the test script ends. Each test waits until its holder is in place before it runs the install or prune script.

This is an alternative to #13907 (keep the fake WSL runtime visible), which fixes the same two failures by appending : to the fixture's sh -c command.

Why

Two tests fail on hosts where /bin/sh is bash, such as Arch and Fedora: removes an aged stale tree after replacing an active unready cache and prunes old and markerless caches without touching retained, active, locked, or unrelated roots. The fixture ran sh -c "sleep 30" <runtime>/t3, and bash runs a lone -c command in place of the shell, so the process's command line becomes just sleep 30. The scripts detect a busy runtime by scanning /proc/*/cmdline for its path, so they treated the "active" cache as idle and removed it. Production is unaffected, since a real server keeps its path in its command line.

The holders now carry the runtime entry as their argv[0] and read a pipe the test script keeps open. The fixture no longer depends on how sh handles -c, nothing sleeps on a 30-second timer, and no holder outlives a test that fails partway. A bounded wait for each holder replaces the fixed sleep 0.1, so a slow runner cannot start the scripts before the holder exists. On Arch the file goes from 2 failed to 50 passed; with the in-use check deliberately broken four tests fail, and with the prune script ignoring install locks the prune test fails.

Checklist

• This PR is small and focused
• I explained what changed and why
• I included before/after screenshots for any UI changes
• I included a video for animation/interaction changes

[macroscopeapp]

Approvability

Verdict: Approved at 74d467f

Macroscope's review found this PR approvable — This is a narrowly scoped, test-only fixture maintenance change confined to ignored paths, with no production request-path or product-default impact. It does not introduce a capability, schema change, deployment change, or static-analysis suppression.

Notes:

• No code objects were reviewed. Approvability was decided on eligibility alone.

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📥 Commits

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• apps/desktop/src/wsl/DesktopWslEnvironment.test.ts

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📝 Walkthrough

Walkthrough

The WSL install and prune tests replace sleep-based background processes with pipe-backed holders. New helpers poll for runtime and install-lock conditions before the tests continue.

Changes

WSL test process holders

Layer / File(s)	Summary
Add and use process-holder helpers apps/desktop/src/wsl/DesktopWslEnvironment.test.ts	The tests use polling helpers and pipe-backed processes to hold a runtime busy or an install lock. They remove sleep-based holders and explicit process cleanup.

Priority: ⬇️ Low

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

Change: Other

Suggested reviewers: juliusmarminge

Merge Risk: ⚪ Minimal · up to 74d46

This change only makes the WSL cache tests more reliable on hosts where sh is bash. It does not change runtime behavior, so merge risk is minimal.

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title clearly and concisely describes the main change: updating desktop WSL test fixtures so busy runtimes remain visible when /bin/sh is bash.
Description check	✅ Passed	The description explains what changed, why the change is needed, and how the new test holders work. The checklist confirms that the PR is focused and includes the required rationale. The unchecked UI …
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check. Docstring coverage is scoped to functions touched by this diff. Analyzed 0 functions across 1…
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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