fix/coverage-ignore-brda-61586

[PradSharma554]

---

Summary

Fixes #61586

/* node:coverage ignore next */ comments were not properly excluding branches from LCOV coverage output. When a branch was ignored, the LCOV reporter still emitted BRDA entries with count=0, causing BRF (branches
found) to exceed BRH (branches hit) even though the uncovered code was supposed to be ignored.

Root Cause

V8's block coverage ranges for branches can include structural elements like closing braces (}) that belong to the parent scope. The existing check range.ignoredLines === range.lines.length fails in this case
because the closing brace line isn't marked as ignored — it's covered by the parent function range.

For example:

  function getValue(condition) {
    if (condition) {
      return 'truthy';
    }                                    // ← line covered by parent range, not ignored
    /* node:coverage ignore next */
    return 'falsy';                      // ← ignored
  }

V8's false branch range spans from return 'falsy' to }. Since } isn't ignored, ignoredLines !== lines.length, so the branch wasn't excluded.

Fix

1. Mark the ignore comment line itself as ignored (coverageLine.ignore = true), so it no longer counts as an uncovered line.
2. Add a secondary check in summary(): for uncovered branches (count === 0) that contain ignored lines (ignoredLines > 0), skip the branch if all non-ignored lines are already covered (count > 0) by other ranges.
   This handles the case where V8's branch range includes structural lines covered by the parent range, but the actual uncovered code is all on ignored lines.

Test Coverage

• getValue() — branch where false path is fully ignored → branch excluded from LCOV
• getMixed() — branch with both ignored and non-ignored uncovered code → branch correctly kept in LCOV

---

[nodejs-github-bot]

Review requested:

• @nodejs/test_runner

[avivkeller]

@PradSharma554 can you please give your PR a proper description explaining what/why/how?

[codecov]

Codecov Report

❌ Patch coverage is 86.36364% with 3 lines in your changes missing coverage. Please review.
✅ Project coverage is 89.68%. Comparing base (ae228c1) to head (1c9bd19).
⚠️ Report is 25 commits behind head on main.

Files with missing lines	Patch %	Lines
lib/internal/test_runner/coverage.js	86.36%	3 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #62264      +/-   ##
==========================================
+ Coverage   89.65%   89.68%   +0.02%     
==========================================
  Files         676      676              
  Lines      206546   206575      +29     
  Branches    39558    39560       +2     
==========================================
+ Hits       185179   185260      +81     
+ Misses      13485    13451      -34     
+ Partials     7882     7864      -18     

Files with missing lines	Coverage Δ
lib/internal/test_runner/coverage.js	64.76% <86.36%> (+0.57%)	⬆️

... and 49 files with indirect coverage changes

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[PradSharma554]

@PradSharma554 can you please give your PR a proper description explaining what/why/how?

Okay
Lemme make some minor changes related to the PR first

[PradSharma554]

@avivkeller Can you review it now?

[JakobJingleheimer]

Duplicate of #61598

[PradSharma554]

Duplicate of #61598

then shall i not work on this?

[JakobJingleheimer]

The cited PR was the first one and the furthest along. So, I would guess probably not?

Also, there are like 5 other PRs to fix this issue—probably best to check that before starting 🙂 (they're all linked to/from the hug report)

[PradSharma554]

The cited PR was the first one and the furthest along. So, I would guess probably not?

Also, there are like 5 other PRs to fix this issue—probably best to check that before starting 🙂 (they're all linked to/from the hug report)

Okay! I'll pick up something else