mkvenv: use pip's vendored distlib as a fallback

distlib is usually not installed on Linux distribution, but it is vendored
into pip.  Because the virtual environment has pip via ensurepip, we
can piggy-back on pip's vendored version.  This could break if they move
our cheese in the future, but the fix would be simply to require distlib.

If it is debundled, as it is on msys, it is simply available directly.

Signed-off-by: John Snow <jsnow@redhat.com>
[Move to toplevel. - Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
John Snow 2023-05-16 09:05:51 +02:00 committed by Paolo Bonzini
parent 928348949d
commit 68ea6d17fe
2 changed files with 40 additions and 3 deletions

View File

@ -69,10 +69,25 @@ from typing import (
import venv
import warnings
import distlib.database
import distlib.scripts
import distlib.version
# Try to load distlib, with a fallback to pip's vendored version.
# HAVE_DISTLIB is checked below, just-in-time, so that mkvenv does not fail
# outside the venv or before a potential call to ensurepip in checkpip().
HAVE_DISTLIB = True
try:
import distlib.database
import distlib.scripts
import distlib.version
except ImportError:
try:
# Reach into pip's cookie jar. pylint and flake8 don't understand
# that these imports will be used via distlib.xxx.
from pip._vendor import distlib
import pip._vendor.distlib.database # noqa, pylint: disable=unused-import
import pip._vendor.distlib.scripts # noqa, pylint: disable=unused-import
import pip._vendor.distlib.version # noqa, pylint: disable=unused-import
except ImportError:
HAVE_DISTLIB = False
# Do not add any mandatory dependencies from outside the stdlib:
# This script *must* be usable standalone!
@ -664,6 +679,10 @@ def ensure(
bellwether for the presence of 'sphinx'.
"""
print(f"mkvenv: checking for {', '.join(dep_specs)}", file=sys.stderr)
if not HAVE_DISTLIB:
raise Ouch("a usable distlib could not be found, please install it")
try:
_do_ensure(dep_specs, online, wheels_dir)
except subprocess.CalledProcessError as exc:

View File

@ -125,6 +125,24 @@ ignore_missing_imports = True
[mypy-distlib.version]
ignore_missing_imports = True
[mypy-pip]
ignore_missing_imports = True
[mypy-pip._vendor]
ignore_missing_imports = True
[mypy-pip._vendor.distlib]
ignore_missing_imports = True
[mypy-pip._vendor.distlib.database]
ignore_missing_imports = True
[mypy-pip._vendor.distlib.scripts]
ignore_missing_imports = True
[mypy-pip._vendor.distlib.version]
ignore_missing_imports = True
[pylint.messages control]
# Disable the message, report, category or checker with the given id(s). You
# can either give multiple identifiers separated by comma (,) or put this