pre-commit/pre_commit/languages/python.py

from __future__ import annotations

import contextlib
import functools
import os
import sys
import tempfile
from collections.abc import Generator
from collections.abc import Sequence
from pathlib import Path

import tomlkit
from tomlkit import TOMLDocument

import pre_commit.constants as C
from pre_commit import lang_base
from pre_commit.envcontext import envcontext
from pre_commit.envcontext import PatchesT
from pre_commit.envcontext import UNSET
from pre_commit.envcontext import Var
from pre_commit.parse_shebang import find_executable
from pre_commit.prefix import Prefix
from pre_commit.util import CalledProcessError
from pre_commit.util import cmd_output
from pre_commit.util import cmd_output_b
from pre_commit.util import win_exe

ENVIRONMENT_DIR = 'py_env'
run_hook = lang_base.basic_run_hook


@functools.cache
def _version_info(exe: str) -> str:
    prog = 'import sys;print(".".join(str(p) for p in sys.version_info))'
    try:
        return cmd_output(exe, '-S', '-c', prog)[1].strip()
    except CalledProcessError:
        return f'<<error retrieving version from {exe}>>'


def _read_pyvenv_cfg(filename: str) -> dict[str, str]:
    ret = {}
    with open(filename, encoding='UTF-8') as f:
        for line in f:
            try:
                k, v = line.split('=')
            except ValueError:  # blank line / comment / etc.
                continue
            else:
                ret[k.strip()] = v.strip()
    return ret


def bin_dir(venv: str) -> str:
    """On windows there's a different directory for the virtualenv"""
    bin_part = 'Scripts' if sys.platform == 'win32' else 'bin'
    return os.path.join(venv, bin_part)


def get_env_patch(venv: str) -> PatchesT:
    return (
        ('PIP_DISABLE_PIP_VERSION_CHECK', '1'),
        ('PYTHONHOME', UNSET),
        ('VIRTUAL_ENV', venv),
        ('PATH', (bin_dir(venv), os.pathsep, Var('PATH'))),
    )


def _find_by_py_launcher(
        version: str,
) -> str | None:  # pragma: no cover (windows only)
    if version.startswith('python'):
        num = version.removeprefix('python')
        cmd = ('py', f'-{num}', '-c', 'import sys; print(sys.executable)')
        env = dict(os.environ, PYTHONIOENCODING='UTF-8')
        try:
            return cmd_output(*cmd, env=env)[1].strip()
        except CalledProcessError:
            pass
    return None


def _find_by_sys_executable() -> str | None:
    def _norm(path: str) -> str | None:
        _, exe = os.path.split(path.lower())
        exe, _, _ = exe.partition('.exe')
        if exe not in {'python', 'pythonw'} and find_executable(exe):
            return exe
        return None

    # On linux, I see these common sys.executables:
    #
    # system `python`: /usr/bin/python -> python2.7
    # system `python2`: /usr/bin/python2 -> python2.7
    # virtualenv v: v/bin/python (will not return from this loop)
    # virtualenv v -ppython2: v/bin/python -> python2
    # virtualenv v -ppython2.7: v/bin/python -> python2.7
    # virtualenv v -ppypy: v/bin/python -> v/bin/pypy
    for path in (sys.executable, os.path.realpath(sys.executable)):
        exe = _norm(path)
        if exe:
            return exe
    return None


@functools.lru_cache(maxsize=1)
def get_default_version() -> str:  # pragma: no cover (platform dependent)
    # First attempt from `sys.executable` (or the realpath)
    exe = _find_by_sys_executable()
    if exe:
        return exe

    # Next try the `pythonX.X` executable
    exe = f'python{sys.version_info[0]}.{sys.version_info[1]}'
    if find_executable(exe):
        return exe

    if _find_by_py_launcher(exe):
        return exe

    # We tried!
    return C.DEFAULT


def _sys_executable_matches(version: str) -> bool:
    if version == 'python':
        return True
    elif not version.startswith('python'):
        return False

    try:
        info = tuple(int(p) for p in version.removeprefix('python').split('.'))
    except ValueError:
        return False

    return sys.version_info[:len(info)] == info


def norm_version(version: str) -> str | None:
    if version == C.DEFAULT:  # use virtualenv's default
        return None
    elif _sys_executable_matches(version):  # virtualenv defaults to our exe
        return None

    if sys.platform == 'win32':  # pragma: no cover (windows)
        version_exec = _find_by_py_launcher(version)
        if version_exec:
            return version_exec

        # Try looking up by name
        version_exec = find_executable(version)
        if version_exec and version_exec != version:
            return version_exec

    # Otherwise assume it is a path
    return os.path.expanduser(version)


@contextlib.contextmanager
def in_env(prefix: Prefix, version: str) -> Generator[None, None, None]:
    envdir = lang_base.environment_dir(prefix, ENVIRONMENT_DIR, version)
    with envcontext(get_env_patch(envdir)):
        yield


def health_check(prefix: Prefix, version: str) -> str | None:
    envdir = lang_base.environment_dir(prefix, ENVIRONMENT_DIR, version)
    pyvenv_cfg = os.path.join(envdir, 'pyvenv.cfg')

    # created with "old" virtualenv
    if not os.path.exists(pyvenv_cfg):
        return 'pyvenv.cfg does not exist (old virtualenv?)'

    exe_name = win_exe('python')
    py_exe = prefix.path(bin_dir(envdir), exe_name)
    cfg = _read_pyvenv_cfg(pyvenv_cfg)

    if 'version_info' not in cfg:
        return "created virtualenv's pyvenv.cfg is missing `version_info`"

    # always use uncached lookup here in case we replaced an unhealthy env
    virtualenv_version = _version_info.__wrapped__(py_exe)
    if virtualenv_version != cfg['version_info']:
        return (
            f'virtualenv python version did not match created version:\n'
            f'- actual version: {virtualenv_version}\n'
            f'- expected version: {cfg["version_info"]}\n'
        )

    # made with an older version of virtualenv? skip `base-executable` check
    if 'base-executable' not in cfg:
        return None

    base_exe_version = _version_info(cfg['base-executable'])
    if base_exe_version != cfg['version_info']:
        return (
            f'base executable python version does not match created version:\n'
            f'- base-executable version: {base_exe_version}\n'
            f'- expected version: {cfg["version_info"]}\n'
        )
    else:
        return None


def install_environment(
        prefix: Prefix,
        version: str,
        additional_dependencies: Sequence[str],
) -> None:
    envdir = lang_base.environment_dir(prefix, ENVIRONMENT_DIR, version)
    venv_cmd = [sys.executable, '-mvirtualenv', envdir]
    python = norm_version(version)
    if python is not None:
        venv_cmd.extend(('-p', python))

    cmd_output_b(*venv_cmd, cwd='/')
    with in_env(prefix, version):
        pip_cmd = None
        if 'PRE_COMMIT_USE_UV' in os.environ:
            name = None
            proj_file = prefix.path() / Path('pyproject.toml')
            if proj_file.exists():
                with open(proj_file) as fd:
                    parsed = tomlkit.parse(fd.read())

                    def try_navigate(*coords: str) -> TOMLDocument | None:
                        curr = parsed
                        for coord in coords:
                            if coord not in curr:
                                return None
                            curr = curr[coord]
                        return curr

                    name = try_navigate('tool', 'poetry', 'name')

                    if name is None:
                        name = try_navigate('project', 'name')
            if name is None:
                setup = prefix.prefix_dir / Path('setup.py')
                if setup.exists():
                    with tempfile.TemporaryDirectory() as td:
                        try:
                            lang_base.setup_cmd(
                                prefix,
                                ('uv', 'pip', 'install', 'setuptools'),
                            )
                            lang_base.setup_cmd(
                                prefix,
                                (
                                    'python',
                                    'setup.py',
                                    'egg_info',
                                    '-e',
                                    f'{td}',
                                ),
                            )
                            candidates = list(Path(td).glob('*.egg-info'))
                            if len(candidates) == 1:
                                name = candidates[0].name[
                                    : (-len('.egg-info'))
                                ]

                        except CalledProcessError:
                            pass  # fallback

            if name is not None:
                pip_cmd = (
                    'uv',
                    'pip',
                    'install',
                    f'{name} @ .',
                    *additional_dependencies,
                )
        if pip_cmd is not None:
            try:
                lang_base.setup_cmd(prefix, pip_cmd)
                return
            except CalledProcessError:
                pass  # fallback
        lang_base.setup_cmd(
            prefix,
            (
                'python',
                '-mpip',
                'install',
                '.',
                *additional_dependencies,
            ),
        )