A naive scripts that iterates through version specifiers of the form "package>=version" or "package (>=version)" and updates the version based on the lockfile.

merge_lockfile.py

import re
import tomllib

import click


def sync_dependencies(raw_pyproject: str, dep_list: list[str], lockfile: dict) -> str:
    for dep_string in dep_list:
        match = re.fullmatch(r'(?P<name>[^(@\s]+)\s*\(?>=?(?P<version>[^),]+)\)?\s*', dep_string)

        if match is None:
            continue

        name = match.group('name')
        version = match.group('version')

        for pkginfo in lockfile['package']:
            if pkginfo['name'] == name:
                if version != pkginfo['version']:
                    click.echo(f'Changing version of {name} from {version} to {pkginfo['version']}')
                    updated_dep_string = dep_string.replace(version, pkginfo['version'])
                    raw_pyproject = raw_pyproject.replace(dep_string, updated_dep_string)

                break

    return raw_pyproject


@click.command(help='A naive scripts that iterates through version specifiers of the form "package>=version" or "package (>=version)" and updates the version based on the lockfile.')
@click.option('-p', '--pyproject', default='pyproject.toml', type=click.Path(readable=True, exists=True, dir_okay=False))
@click.option('-l', '--lockfile', type=click.Path(readable=True, exists=False, dir_okay=False))
def merge_lockfile(pyproject: str, lockfile: str | None = None) -> None:
    with open(pyproject) as file:
        raw_pyproject = file.read()
        pyproject_toml = tomllib.loads(raw_pyproject)

    if lockfile is None:
        for stem in ['pylock', 'uv', 'poetry']:
            try:
                with open(stem + '.lock', 'rb') as file:
                    lockfile_toml = tomllib.load(file)
                    break
            except FileNotFoundError:
                pass
        else:
            raise click.ClickException('Could not find a lock file automatically. Consider using the --lockfile option.') from None
    else:
        with open(lockfile, 'rb') as file:
            lockfile_toml = tomllib.load(file)

    if project_section := pyproject_toml.get('project'):
        if dep_list := project_section.get('dependencies'):
            raw_pyproject = sync_dependencies(raw_pyproject, dep_list, lockfile_toml)

        if optional := project_section.get('optional-dependencies'):
            for dep_list in optional.values():
                raw_pyproject = sync_dependencies(raw_pyproject, dep_list, lockfile_toml)

    if groups := pyproject_toml.get('dependency-groups'):
        for dep_list in groups.values():
            raw_pyproject = sync_dependencies(raw_pyproject, dep_list, lockfile_toml)

    with open(pyproject, 'w') as file:
        file.write(raw_pyproject)