Function mergeCoverageScripts

lib/internal/test_runner/coverage.js:669–715

(oldScript, newScript)

}

function mergeCoverageScripts(oldScript, newScript) {
  // Merge the functions from the new coverage into the functions from the
  // existing (merged) coverage.
  for (let i = 0; i < newScript.functions.length; ++i) {
    const newFn = newScript.functions[i];
    let found = false;

    for (let j = 0; j < oldScript.functions.length; ++j) {
      const oldFn = oldScript.functions[j];

      if (newFn.functionName === oldFn.functionName &&
          newFn.ranges?.[0].startOffset === oldFn.ranges?.[0].startOffset &&
          newFn.ranges?.[0].endOffset === oldFn.ranges?.[0].endOffset) {
        // These are the same functions.
        found = true;

        // If newFn is block level coverage, then it will:
        // - Replace oldFn if oldFn is not block level coverage.
        // - Merge with oldFn if it is also block level coverage.
        // If newFn is not block level coverage, then it has no new data.
        if (newFn.isBlockCoverage) {
          if (oldFn.isBlockCoverage) {
            // Merge the oldFn ranges with the newFn ranges.
            mergeCoverageRanges(oldFn, newFn);
          } else {
            // Replace oldFn with newFn.
            oldFn.isBlockCoverage = true;
            oldFn.ranges = newFn.ranges;
          }
        }

        break;
      }
    }

    if (!found) {
      // This is a new function to track. This is possible because V8 can
      // generate a different list of functions depending on which code paths
      // are executed. For example, if a code path dynamically creates a
      // function, but that code path is not executed then the function does
      // not show up in the coverage report. Unfortunately, this also means
      // that the function counts in the coverage summary can never be
      // guaranteed to be 100% accurate.
      ArrayPrototypePush(oldScript.functions, newFn);
    }
  }
}

function mergeCoverageRanges(oldFn, newFn) {
  const mergedRanges = new SafeSet();