python-poetry/poetry · error · ValueError

Invalid author string. Must be in the format: John Smith <jo

Error message

Invalid author string. Must be in the format: John Smith <john@example.com>

What it means

ValueError from `_validate_author` (init.py:508-513) when the author string (after unicode combining) does not match `AUTHOR_REGEX`, which expects `Name <email>`. Used by `poetry init` to populate `authors` in pyproject.toml.

Source

Thrown at src/poetry/console/commands/init.py:510

                constraint.update(requirement)

            requires[name] = constraint

        return requires

    @staticmethod
    def _validate_author(author: str, default: str) -> str | None:
        from poetry.core.utils.helpers import combine_unicode
        from poetry.core.utils.patterns import AUTHOR_REGEX

        author = combine_unicode(author or default)

        if author in ["n", "no"]:
            return None

        m = AUTHOR_REGEX.match(author)
        if not m:
            raise ValueError(
                "Invalid author string. Must be in the format: "
                "John Smith <john@example.com>"
            )

        return author

    @staticmethod
    def _validate_package(package: str | None) -> str | None:
        if package and len(package.split()) > 2:
            raise ValueError("Invalid package definition.")

        return package

    @staticmethod
    def _validate_version_constraint(constraint: str | None) -> str | None:
        from poetry.core.constraints.version import parse_constraint

        constraint = (constraint or "").strip()

View on GitHub (pinned to 92b74dcfe3)

Solutions

1. Use the exact format `John Smith <john@example.com>`.
2. Omit authors by entering `n` or `no` at the prompt.
3. For non-ASCII names, ensure the terminal is UTF-8 and the combined form still matches `Name <email>`.

Example fix

# before
John Smith, john@example.com
# after
John Smith <john@example.com>

import re
from poetry.core.utils.patterns import AUTHOR_REGEX
from poetry.core.utils.helpers import combine_unicode
author = combine_unicode("John Smith <john@example.com>")
if not AUTHOR_REGEX.match(author):
    raise SystemExit("author must be 'Name <email>'")

def is_valid_author(value: str) -> bool:
    from poetry.core.utils.patterns import AUTHOR_REGEX
    from poetry.core.utils.helpers import combine_unicode
    return bool(AUTHOR_REGEX.match(combine_unicode(value or "")))

When it happens

Trigger: Entering `John Smith` without an email; `john@example.com` without a name; reversed order `john@example.com (John Smith)`; embedded newline or stray characters.

Common situations: Skipping the email during interactive init; pasting from a vCard; non-ASCII names that break the regex after `combine_unicode`.

Related errors

• Invalid package definition.
• Invalid version constraint: {constraint}
• Setting {self.argument('key')} does not exist
• You can only pass one value.
• "{value}" is an invalid value for {key}

AI-assisted analysis of python-poetry/poetry@92b74dcfe3 (2026-08-04). Data as JSON: /data/errors/730963aef4a4350c.json. Report an issue: GitHub.