pypa/pip · error · ConfigurationError

Fatal Internal error [id=1]. Please report as a bug.

Error message

Fatal Internal error [id=1]. Please report as a bug.

What it means

Raised as ConfigurationError in Configuration.unset_value() at configuration.py:196-202 when the in-memory state said the key exists but the underlying RawConfigParser reports the section is absent or parser.remove_option(section, name) returns False. This indicates an internal inconsistency between pip's cached config view and the parser — a state the code considers unreachable, hence the 'report as a bug' message (id=1).

Source

Thrown at src/pip/_internal/configuration.py:200

        key = _normalize_name(key)
        self._ensure_have_load_only()

        assert self.load_only
        fname, parser = self._get_parser_to_modify()

        if (
            key not in self._config[self.load_only][fname]
            and key not in self._config[self.load_only]
        ):
            raise ConfigurationError(f"No such key - {orig_key}")

        if parser is not None:
            section, name = _disassemble_key(key)
            if not (
                parser.has_section(section) and parser.remove_option(section, name)
            ):
                # The option was not removed.
                raise ConfigurationError(
                    "Fatal Internal error [id=1]. Please report as a bug."
                )

            # The section may be empty after the option was removed.
            if not parser.items(section):
                parser.remove_section(section)
            self._mark_as_modified(fname, parser)
        try:
            del self._config[self.load_only][fname][key]
        except KeyError:
            del self._config[self.load_only][key]

    def save(self) -> None:
        """Save the current in-memory state."""
        self._ensure_have_load_only()

        for fname, parser in self._modified_parsers:
            logger.info("Writing to %s", fname)

View on GitHub (pinned to d7d0d0a394)

Solutions

1. Report it as a bug to pip with the exact sequence that triggered it.
2. Manually edit the config file to remove the offending key, then retry.
3. Restart the command — if it was a transient concurrent-edit, a fresh run on a stable file should succeed.
4. Run 'pip config debug' to inspect the parsed state of all config files.

# No reliable pre-validation; this is an internal inconsistency.
# Mitigate by ensuring no concurrent edits to the config file while pip runs.
import fcntl, os
lockpath = os.path.expanduser('~/.pip/pip.conf.lock')
with open(lockpath, 'w') as lock:
    fcntl.flock(lock, fcntl.LOCK_EX)
    # run pip config unset here

from pip._internal.exceptions import ConfigurationError
try:
    cfg.unset_value('global.foo')
except ConfigurationError as e:
    if 'Fatal Internal error' in str(e):
        # resync: reload config from disk and retry once, or edit the file manually
        cfg.load()
    else:
        raise

When it happens

Trigger: An internal desynchronization between self._config (the dict view) and the RawConfigParser objects after concurrent modification, a hand-edited config file changed underneath pip, or a bug in pip's own bookkeeping. The guard at configuration.py:196-198 fires when the parser cannot remove the option it was told to remove.

Common situations: Editing the pip.conf file externally while a 'pip config unset' runs; a pip bug in older versions; corrupted config parsing state. This is genuinely rare and almost always indicates a pip bug or external file mutation.

Related errors

• Internal Error.
• Key does not contain dot separated section and key. Perhaps
• Got invalid value for load_only - should be one of {}
• No such key - {orig_key}
• An error occurred while writing to the configuration file {f

AI-assisted analysis of pypa/pip@d7d0d0a394 (2026-08-04). Data as JSON: /data/errors/a421cfee20fdf804.json. Report an issue: GitHub.