nodejs/node · error · Exception

Malformed line: '%s'.

Error message

Malformed line: '%s'.

What it means

The test runner parses status files (the .status files that express expected results/conditions per test path). Each meaningful line must match either a definition pattern (key = condition) or a path-prefix pattern; any line matching neither is rejected as malformed.

Source

Thrown at tools/test.py:1376

      value_str = rule_match.group(2).strip()
      value = ParseCondition(value_str)
      if not value:
        return False
      current_section.AddRule(Rule(rule_match.group(1), path, value))
      continue
    def_match = DEF_PATTERN.match(line)
    if def_match:
      name = def_match.group(1).lower()
      value = ParseCondition(def_match.group(2).strip())
      if not value:
        return False
      defs[name] = value
      continue
    prefix_match = PREFIX_PATTERN.match(line)
    if prefix_match:
      prefix = SplitPath(prefix_match.group(1).strip())
      continue
    raise Exception("Malformed line: '%s'." % line)


# ---------------
# --- M a i n ---
# ---------------


ARCH_GUESS = utils.GuessArchitecture()


def BuildOptions():
  result = argparse.ArgumentParser()
  result.add_argument("-m", "--mode", help="The test modes in which to run (comma-separated)",
      default='release')
  result.add_argument("-v", "--verbose", help="Verbose output",
      default=False, action="store_true")
  result.add_argument('--logfile', dest='logfile',
      help='write test output to file. NOTE: this only applies the tap progress indicator')

View on GitHub (pinned to 1b2de5e052)

Solutions

1. Open the file named in the error and fix the offending line to match the status-file grammar (key = condition, or a valid path prefix).
2. Remove any `<<<<<<<`/`=======`/`>>>>>>>` merge-conflict markers.
3. Re-save the file as UTF-8 without BOM and LF line endings.

Example fix

// before (in test/parallel/.status)
  parallel/test-foo PASS,FLAKY       # malformed: missing '=' grammar
// after
  parallel/test-foo: PASS,FLAKY      # use the documented prefix/condition form

# cheap pre-check: every non-comment, non-blank line matches DEF or PREFIX
import re
ok = re.compile(r'^\s*(#.*)?$')
assert all(ok.match(l) or DEF_PATTERN.match(l) or PREFIX_PATTERN.match(l)
           for l in open(status_file)), f'{status_file} has a malformed line'

When it happens

Trigger: A syntax error in a .status file: a stray token, a malformed condition, a missing '=', or a prefix line in the wrong shape.

Common situations: Hand-editing a .status file; unresolved git merge-conflict markers left in it; a BOM or CRLF/CRLF-only encoding issue; copy-paste introducing invisible characters.

Understand the failure class

• Parsing and encoding errors: unexpected token, malformed input — why parsers reject input and how to find the real culprit.

Related errors

• Could not find executable. Should be
• Cannot find out dir, did you run build?
• Every filter in --filters must start with + or - ({filt} doe
• Could not find pattern matching %s
• No Node inspector protocol revision found

AI-assisted analysis of nodejs/node@1b2de5e052 (2026-08-13). Data as JSON: /api/errors/34190380e42308a6. Report an issue: GitHub.