fix(scripts): only swallow ENOENT in rees-coverage lcov post-process (#7771)

[RealDiligent]

Summary

• Narrow the bare catch{} in rees-coverage.mjs to only swallow ENOENT on read; re-throw all other errors (e.g. write failures)
• Export normalizeLcovSfPaths with injectable read/write for unit tests; guard main() behind import.meta.url check
• Add rees-coverage.d.mts type declarations and unit tests covering ENOENT swallow, write-failure propagation, and backslash normalization

Closes #7771

Test plan

• npm run typecheck passes locally
• CI validate-code + validate-tests green
• codecov/patch >= 99% on changed lines

Made with Cursor

[superagent-security]

Superagent did not find any vulnerabilities or security issues in this PR.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 88.57%. Comparing base (ea7da0c) to head (2218d83).
⚠️ Report is 2 commits behind head on main.
✅ All tests successful. No failed tests found.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #7815   +/-   ##
=======================================
  Coverage   88.57%   88.57%           
=======================================
  Files         725      725           
  Lines       76409    76409           
  Branches    22762    22760    -2     
=======================================
  Hits        67682    67682           
  Misses       7681     7681           
  Partials     1046     1046           

Flag	Coverage Δ
shard-1	55.07% <ø> (-0.34%)	⬇️
shard-2	50.60% <ø> (-1.98%)	⬇️
shard-3	48.42% <ø> (+1.04%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

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Tip

✅ LoopOver review result - approve/merge recommended

_{Review updated: 2026-07-21 13:29:05 UTC}

3 files · 1 AI reviewer · no blockers · readiness 98/100 · CI green · clean

✅ Suggested Action - Approve/Merge

• safe to merge

Review summary
This PR narrows a bare `catch{}` in rees-coverage.mjs to only swallow ENOENT on the lcov read, re-throwing any other error (e.g. an EACCES write failure) instead of silently masking it — a legitimate root-cause fix. It also extracts the normalization logic into an exported, dependency-injectable `normalizeLcovSfPaths` function, adds a matching `.d.mts` declaration, and guards `main()` behind an `import.meta.url` check so the script is safely importable for unit tests. The three new tests (ENOENT swallow, write-failure propagation, backslash normalization) exercise the exported function directly as it's actually called in `main()`, so they cover the real path rather than a fabricated one.

Nits — 4 non-blocking

• scripts/rees-coverage.mjs: the JSDoc comment above `normalizeLcovSfPaths` is fairly long for a small helper — could be trimmed to the ENOENT-swallow rationale alone.
• The `console.error` at scripts/rees-coverage.mjs:42 for the empty-tests case is pre-existing behavior moved into `main()`, not new logging from this PR — worth confirming reviewers don't misflag it as a new debug leftover.
• Consider a fourth test asserting `main()` itself is a no-op on import (i.e., the `import.meta.url` guard prevents side effects when the module is required by the test file), since that guard is otherwise untested.
• scripts/rees-coverage.d.mts could reuse `NodeJS.ErrnoException`-shaped typing for consistency with the test file's error typing, though the current loose signature is fine for this narrow surface.

Decision drivers

• ✅ Code review — No blockers (1 reviewer)
• ✅ Gate result — Passing (No configured blocker found.)

Context & advisory signals — never blocks the verdict

Signal	Result	Evidence
Linked issue	✅ Linked	#7771
Related work	✅ No active overlap found	No same-issue or scoped active PR overlap found.
Change scope	✅ 20/20	Low review scope from cached public metadata (1 linked issue).
Validation posture	✅ 25/25	PR body includes validation/test evidence.
Contributor workload	✅ 10/10	Author activity: 395 registered-repo PR(s), 185 merged, 36 issue(s).
Contributor context	✅ Confirmed Gittensor contributor	RealDiligent; Gittensor profile; 395 PR(s), 36 issue(s).
Improvement	✅ Minor	risk: clean · value: minor · LLM: moderate

Linked issue satisfaction

Addressed
The catch block now only swallows errors with error.code === "ENOENT" and re-throws everything else, directly matching the requirement, and the PR adds regression tests covering the ENOENT pass-through, a simulated write failure propagating, and path normalization behavior.

Review context

• Author: RealDiligent
• Role context: outside_contributor
• Public audience mode: oss maintainer
• Lane context: Repository is configured for direct PR review.
• Public profile languages: Python, JavaScript, Ruby, Svelte, TypeScript, Markdown, MDX
• Official Gittensor activity: 395 PR(s), 36 issue(s).
• PR-specific overlap: none found.

Contributor next steps

• Keep the PR focused and include validation evidence before maintainer review.

Signal definitions

• Related work = same linked issue, overlapping active PRs, or title/path similarity.
• Change scope = cached public metadata such as size labels, draft state, and review-burden hints.
• Validation posture = whether the PR provides enough public validation/test evidence for maintainer review.
• Contributor workload = public contributor activity and cleanup pressure, not a repo-wide quality failure.
• Contributor context = public GitHub/Gittensor identity context; non-Gittensor status is not a blocker.

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_{🟩 Safe / merged · 🟦 Advisory · 🟨 Held for review · 🟥 Blocked / closed}

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LoopOver approves — the gate is satisfied and CI is green.