nodejs/node · error · Exception

results_regexp at the wrong level. Regexp should not contain

Error message

results_regexp at the wrong level. Regexp should not contain '%%s': results_regexp='%s' name=%s

What it means

LeafTraceConfig represents a leaf of the suite tree; its results_regexp must be fully resolved (no `%s` placeholder). A `%s` here means a parent-level templated regexp leaked into a leaf un-substituted — i.e. the regexp is at the wrong tree level.

Source

Thrown at deps/v8/tools/run_perf.py:459

  def __init__(self, suite, parent, arch):
    super(VariantConfig, self).__init__(suite, parent, arch)
    assert "variants" in suite
    for variant in suite.get('variants'):
      assert "variants" not in variant, \
        "Cannot directly nest variants:" + str(variant)[:100]
      assert "name" in variant, \
          "Variant must have 'name' property: " + str(variant)[:100]
      assert len(variant) >= 2, \
          "Variant must define other properties than 'name': " + str(variant)


class LeafTraceConfig(GraphConfig):
  """Represents a leaf in the suite tree structure."""
  def __init__(self, suite, parent, arch):
    super(LeafTraceConfig, self).__init__(suite, parent, arch)
    assert self.results_regexp
    if '%s' in self.results_regexp:
      raise Exception(
          "results_regexp at the wrong level. "
          "Regexp should not contain '%%s': results_regexp='%s' name=%s" %
          (self.results_regexp, self.name))

  def AppendChild(self, node):
    raise Exception("%s cannot have child configs." % type(self).__name__)

  def ConsumeOutput(self, output, result_tracker):
    """Extracts trace results from the output.

    Args:
      output: Output object from the test run.
      result_tracker: Result tracker to be updated.

    Returns:
      The raw extracted result value or None if an error occurred.
    """

View on GitHub (pinned to 1b2de5e052)

Solutions

1. Replace `%s` in the leaf's results_regexp with the literal name (or a concrete regex).
2. Move the templated regexp up to the parent so the leaf inherits an already-substituted regexp.

Example fix

// before (leaf)
"results_regexp": "%s\\.Runtime: ([0-9]+)"
// after
"results_regexp": "MySuite\\.Runtime: ([0-9]+)"

# When defining a leaf suite, ensure the regexp is fully resolved.
assert '%s' not in leaf_regexp, (
    f'leaf results_regexp must not contain a %s placeholder: {leaf_regexp!r}')

def is_resolved_leaf_regexp(r):
    return isinstance(r, str) and '%s' not in r

When it happens

Trigger: A leaf suite whose resolved results_regexp literally contains the substring `%s`.

Common situations: Copy-pasting a parent-level templated regexp onto a leaf; missing an intermediate VariantConfig/GraphConfig layer that would have substituted the placeholder.

Related errors

• Got error while preparing results_regexp: parent.results_reg
• %s cannot have child configs.
• `${baseKey}` is not a valid npm option
• The `${baseKey}` option is deprecated, and cannot be set in
• The ${key} option is protected, and cannot be retrieved in t

AI-assisted analysis of nodejs/node@1b2de5e052 (2026-08-13). Data as JSON: /api/errors/ac5c6a1d768fefbc. Report an issue: GitHub.