nodejs/node · error · ValueError

Invalid MSVS guid: "%s". Must match regex: "%s".

Error message

Invalid MSVS guid: "%s".  Must match regex: "%s".

What it means

Raised as a ValueError when a target specifies an 'msvs_guid' that does not match the VALID_MSVS_GUID_CHARS regex. The guid is read from the default configuration's msvs_guid and validated before being wrapped in braces. An invalid guid would produce a corrupt .vcproj/.sln that Visual Studio cannot open.

Source

Thrown at tools/gyp/pylib/gyp/generator/msvs.py:978

def _GetGuidOfProject(proj_path, spec):
    """Get the guid for the project.

    Arguments:
      proj_path: Path of the vcproj or vcxproj file to generate.
      spec: The target dictionary containing the properties of the target.
    Returns:
      the guid.
    Raises:
      ValueError: if the specified GUID is invalid.
    """
    # Pluck out the default configuration.
    default_config = _GetDefaultConfiguration(spec)
    # Decide the guid of the project.
    guid = default_config.get("msvs_guid")
    if guid:
        if VALID_MSVS_GUID_CHARS.match(guid) is None:
            raise ValueError(
                'Invalid MSVS guid: "%s".  Must match regex: "%s".'
                % (guid, VALID_MSVS_GUID_CHARS.pattern)
            )
        guid = "{%s}" % guid
    guid = guid or MSVSNew.MakeGuid(proj_path)
    return guid


def _GetMsbuildToolsetOfProject(proj_path, spec, version):
    """Get the platform toolset for the project.

    Arguments:
      proj_path: Path of the vcproj or vcxproj file to generate.
      spec: The target dictionary containing the properties of the target.
      version: The MSVSVersion object.
    Returns:
      the platform toolset string or None.
    """

View on GitHub (pinned to 1b2de5e052)

Solutions

1. Provide the guid as a bare hex string matching the expected pattern (no surrounding braces, valid hex characters).
2. Remove the msvs_guid override entirely to let gyp auto-generate a stable guid via MSVSNew.MakeGuid.
3. Verify the guid against VALID_MSVS_GUID_CHARS.pattern and correct any invalid characters.

Example fix

// before
'targets': [{
  'target_name': 'foo',
  'configurations': { 'Debug': { 'msvs_guid': '{ABC-123}' } }
}]
// after — bare hex, valid char set, correct length
'targets': [{
  'target_name': 'foo',
  'configurations': { 'Debug': { 'msvs_guid': 'AA1BB2CC3DD4EE5FF6A7B8C9D0E1F2A3' } }
}]

import re
VALID = re.compile(r'^[A-Fa-f0-9]{32}$')
guid = 'AA1BB2CC3DD4EE5FF6A7B8C9D0E1F2A3'
if not VALID.match(guid):
    raise ValueError('invalid msvs_guid format')

import re
_VALID = re.compile(r'^[A-Fa-f0-9]{32}$')
def is_valid_msvs_guid(g) -> bool:
    return isinstance(g, str) and bool(_VALID.match(g))

When it happens

Trigger: Setting 'msvs_guid' in a target's configuration to a string containing characters outside the allowed set (typically hex digits without braces/with invalid formatting). VALID_MSVS_GUID_CHARS.match returns None at msvs.py:980.

Common situations: Hardcoding a guid with braces already included (the code adds braces itself); using lowercase/uppercase rules mismatch; a typo or non-hex character in a hand-authored guid; copy-pasting a guid format from a different tool.

Related errors

• Target type %s is not a valid target type for target %s in %
• AddFileConfig: file "%s" not in project.
• expected string; got %r
• expected string list; got %r
• expected bool; got %r

AI-assisted analysis of nodejs/node@1b2de5e052 (2026-08-13). Data as JSON: /api/errors/81c3ec36ddd7d25c. Report an issue: GitHub.