resolveInteractiveFileReference function

String resolveInteractiveFileReference(String text, { InputPromptFileFactory fileOf = _defaultFileOf, })

Resolves an interactive prompt that starts with a pasted file path.

The first whitespace-delimited token is treated as a file reference when it looks path-like (/…, ~/, ./, ../) AND names an existing file. It becomes an explicit [attached file: …] path reference — the marker headless mode uses too — annotated with locally measured stats so the model can judge the cost BEFORE reading:

[attached file: /logs/build.log (97.7 KB · 3412 lines · ~8500
 tokens est.) — read it with your tools]

Size formats as human-readable B/KB/MB; decodable text additionally reports line count and the repo's standard ~4-chars-per-token estimate (the compaction heuristic in token_estimation.dart). Content itself is deliberately NEVER inlined — pasting happens before anyone looked at the size, so the model decides whether and how much to read with its tools (read takes line-range selectors). For files over _attachStatsReadCap the content is not read even for statistics; the size speaks for itself. Everything typed after the path rides along as the instruction.

Conservative by design: a token without a path-like prefix is never converted (plain sentences and bare words stay untouched), and input with no such leading reference returns unchanged.

Implementation

String resolveInteractiveFileReference(
  String text, {
  InputPromptFileFactory fileOf = _defaultFileOf,
}) {
  final token = _leadingPathLikeToken(text);
  if (token == null) return text;
  final file = fileOf(token);
  try {
    if (!file.existsSync()) return text;
  } on Object {
    return text;
  }
  var length = 0;
  try {
    length = file.lengthSync();
  } on Object {
    // Stats are best-effort; an unreadable length still attaches.
  }
  final textStats = _attachTextStats(file, length);
  final stats = [_formatAttachBytes(length), ?textStats].join(' · ');
  final trailing = text.trimLeft().substring(token.length).trim();
  final body =
      '[attached file: ${file.absolute.path} ($stats)'
      ' — read it with your tools]';
  return trailing.isEmpty ? body : '$body\n\n$trailing';
}