Function computeFunctionDiff

scripts/sparc2/src/diff/diffTracker.ts:265–335

* Compute a diff between two files, focusing on function-level changes * @param oldText Previous version of code * @param newText New version of code * @returns A DiffResult with diff text and count of changed lines

(oldText: string, newText: string)

 * @returns A DiffResult with diff text and count of changed lines
 */
function computeFunctionDiff(oldText: string, newText: string): DiffResult {
  // Extract functions from the old and new text
  const oldFunctions = extractFunctions(oldText);
  const newFunctions = extractFunctions(newText);

  const hunks: DiffHunk[] = [];
  let changedFunctionsCount = 0;

  // Compare functions
  const allFunctionNames = new Set([...Object.keys(oldFunctions), ...Object.keys(newFunctions)]);

  for (const funcName of allFunctionNames) {
    const oldFunc = oldFunctions[funcName];
    const newFunc = newFunctions[funcName];

    if (!oldFunc) {
      // Function was added
      changedFunctionsCount++;
      hunks.push({
        oldStart: 0,
        oldLines: 0,
        newStart: newFunc.startLine,
        newLines: newFunc.endLine - newFunc.startLine + 1,
        lines: newFunc.content.split("\n").map((line) => `+${line}`),
      });
    } else if (!newFunc) {
      // Function was removed
      changedFunctionsCount++;
      hunks.push({
        oldStart: oldFunc.startLine,
        oldLines: oldFunc.endLine - oldFunc.startLine + 1,
        newStart: 0,
        newLines: 0,
        lines: oldFunc.content.split("\n").map((line) => `-${line}`),
      });
    } else if (oldFunc.content !== newFunc.content) {
      // Function was modified
      changedFunctionsCount++;

      // Use file diff for the function content
      const functionDiff = computeFileDiff(oldFunc.content, newFunc.content);

      // Adjust line numbers to be relative to the file
      for (const hunk of functionDiff.hunks) {
        hunks.push({
          oldStart: oldFunc.startLine + hunk.oldStart,
          oldLines: hunk.oldLines,
          newStart: newFunc.startLine + hunk.newStart,
          newLines: hunk.newLines,
          lines: hunk.lines,
        });
      }
    }
  }

  // Generate the diff text
  const diffLines: string[] = [];