Function extractValidLineRanges

src/codeScan/util/diffLineRanges.ts:60–149

(unifiedDiff: string)

 * ```
 */
export function extractValidLineRanges(unifiedDiff: string): FileLineRanges {
  const ranges: FileLineRanges = new Map();

  if (!unifiedDiff || unifiedDiff.trim() === '') {
    return ranges;
  }

  const lines = unifiedDiff.split('\n');
  let currentFile: string | null = null;
  let currentRanges: LineRange[] = [];
  let currentNewLine = 0;
  let hunkStartLine = 0;

  for (const line of lines) {
    // Match file header: diff --git a/path b/path
    // or +++ b/path (for new file path)
    const fileMatch = line.match(/^\+\+\+ b\/(.+)$/);
    if (fileMatch) {
      // Close current hunk if we have one (before switching files)
      if (currentFile && hunkStartLine > 0 && currentNewLine > hunkStartLine) {
        currentRanges.push({
          start: hunkStartLine,
          end: currentNewLine - 1,
        });
      }

      // Save previous file's ranges
      if (currentFile && currentRanges.length > 0) {
        ranges.set(currentFile, currentRanges);
      }

      currentFile = fileMatch[1];
      currentRanges = [];
      currentNewLine = 0;
      hunkStartLine = 0;
      continue;
    }

    // Match hunk header: @@ -old,count +new,count @@
    const hunkHeader = parseHunkHeader(line);
    if (hunkHeader && currentFile) {
      // Save the previous hunk's range if we have one
      if (hunkStartLine > 0 && currentNewLine > hunkStartLine) {
        currentRanges.push({
          start: hunkStartLine,
          end: currentNewLine - 1,
        });
      }

      // Start tracking new hunk
      hunkStartLine = hunkHeader.newStart;
      currentNewLine = hunkHeader.newStart;

      // For hunks with 0 lines in new file (pure deletion), don't start a range
      if (hunkHeader.newCount === 0) {
        hunkStartLine = 0;
      }
      continue;