Function collectRefToRef

packages/computer/src/git/diff.ts:196–229

(
  opts: DiffWithDeps,
  dir: string,
  from: string,
  to: string,
)

// lists — git's own object database, no working-tree probes —
// and resolve each path's blob in both commits.
async function collectRefToRef(
  opts: DiffWithDeps,
  dir: string,
  from: string,
  to: string,
): Promise<DiffEntry[]> {
  let fromOid: string;
  let toOid: string;
  try {
    fromOid = await opts.git.resolveRef({ fs: opts.fs, dir, ref: from });
    toOid = await opts.git.resolveRef({ fs: opts.fs, dir, ref: to });
  } catch {
    return [];
  }
  const fromFiles = new Set(await listFilesAt(opts.git, opts.fs, dir, from));
  const toFiles = new Set(await listFilesAt(opts.git, opts.fs, dir, to));
  const union = new Set<string>([...fromFiles, ...toFiles]);
  const pathFilter = makePathFilter(opts.paths);

  const entries: DiffEntry[] = [];
  for (const filepath of [...union].sort()) {
    if (!pathFilter(filepath)) continue;
    const inFrom = fromFiles.has(filepath);
    const inTo = toFiles.has(filepath);
    const a = inFrom
      ? await readBlobAsText(opts.git, opts.fs, dir, fromOid, filepath, opts.cache)
      : "";
    const b = inTo ? await readBlobAsText(opts.git, opts.fs, dir, toOid, filepath, opts.cache) : "";
    if (a === b) continue;
    const status: DiffEntry["status"] = !inFrom ? "A" : !inTo ? "D" : "M";
    entries.push({ path: filepath, status, oldText: a, newText: b });
  }
  return entries;
}

/**
 * Count added / removed content lines in a unified patch. Only