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gh-93259: Validate arg to Distribution.from_name. (GH-94270)
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Syncs with importlib_metadata 4.12.0.
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jaraco authored Jun 26, 2022
1 parent 9af6b75 commit 38612a0
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39 changes: 31 additions & 8 deletions Doc/library/importlib.metadata.rst
Original file line number Diff line number Diff line change
Expand Up @@ -13,13 +13,13 @@

**Source code:** :source:`Lib/importlib/metadata/__init__.py`

``importlib.metadata`` is a library that provides for access to installed
package metadata. Built in part on Python's import system, this library
``importlib.metadata`` is a library that provides access to installed
package metadata, such as its entry points or its
top-level name. Built in part on Python's import system, this library
intends to replace similar functionality in the `entry point
API`_ and `metadata API`_ of ``pkg_resources``. Along with
:mod:`importlib.resources` (with new features backported to the
`importlib_resources`_ package), this can eliminate the need to use the older
and less efficient
:mod:`importlib.resources`,
this package can eliminate the need to use the older and less efficient
``pkg_resources`` package.

By "installed package" we generally mean a third-party package installed into
Expand All @@ -32,6 +32,13 @@ By default, package metadata can live on the file system or in zip archives on
anywhere.


.. seealso::

https://importlib-metadata.readthedocs.io/
The documentation for ``importlib_metadata``, which supplies a
backport of ``importlib.metadata``.


Overview
========

Expand All @@ -54,9 +61,9 @@ You can get the version string for ``wheel`` by running the following:
>>> version('wheel') # doctest: +SKIP
'0.32.3'
You can also get the set of entry points keyed by group, such as
You can also get a collection of entry points selectable by properties of the EntryPoint (typically 'group' or 'name'), such as
``console_scripts``, ``distutils.commands`` and others. Each group contains a
sequence of :ref:`EntryPoint <entry-points>` objects.
collection of :ref:`EntryPoint <entry-points>` objects.

You can get the :ref:`metadata for a distribution <metadata>`::

Expand Down Expand Up @@ -91,7 +98,7 @@ Query all entry points::
>>> eps = entry_points() # doctest: +SKIP

The ``entry_points()`` function returns an ``EntryPoints`` object,
a sequence of all ``EntryPoint`` objects with ``names`` and ``groups``
a collection of all ``EntryPoint`` objects with ``names`` and ``groups``
attributes for convenience::

>>> sorted(eps.groups) # doctest: +SKIP
Expand Down Expand Up @@ -174,6 +181,13 @@ all the metadata in a JSON-compatible form per :PEP:`566`::
>>> wheel_metadata.json['requires_python']
'>=2.7, !=3.0.*, !=3.1.*, !=3.2.*, !=3.3.*'

.. note::

The actual type of the object returned by ``metadata()`` is an
implementation detail and should be accessed only through the interface
described by the
`PackageMetadata protocol <https://importlib-metadata.readthedocs.io/en/latest/api.html#importlib_metadata.PackageMetadata>`.

.. versionchanged:: 3.10
The ``Description`` is now included in the metadata when presented
through the payload. Line continuation characters have been removed.
Expand Down Expand Up @@ -295,6 +309,15 @@ The full set of available metadata is not described here. See :pep:`566`
for additional details.


Distribution Discovery
======================

By default, this package provides built-in support for discovery of metadata for file system and zip file packages. This metadata finder search defaults to ``sys.path``, but varies slightly in how it interprets those values from how other import machinery does. In particular:

- ``importlib.metadata`` does not honor :class:`bytes` objects on ``sys.path``.
- ``importlib.metadata`` will incidentally honor :py:class:`pathlib.Path` objects on ``sys.path`` even though such values will be ignored for imports.


Extending the search algorithm
==============================

Expand Down
48 changes: 34 additions & 14 deletions Lib/importlib/metadata/__init__.py
Original file line number Diff line number Diff line change
Expand Up @@ -543,21 +543,21 @@ def locate_file(self, path):
"""

@classmethod
def from_name(cls, name):
def from_name(cls, name: str):
"""Return the Distribution for the given package name.
:param name: The name of the distribution package to search for.
:return: The Distribution instance (or subclass thereof) for the named
package, if found.
:raises PackageNotFoundError: When the named package's distribution
metadata cannot be found.
:raises ValueError: When an invalid value is supplied for name.
"""
for resolver in cls._discover_resolvers():
dists = resolver(DistributionFinder.Context(name=name))
dist = next(iter(dists), None)
if dist is not None:
return dist
else:
if not name:
raise ValueError("A distribution name is required.")
try:
return next(cls.discover(name=name))
except StopIteration:
raise PackageNotFoundError(name)

@classmethod
Expand Down Expand Up @@ -945,13 +945,26 @@ def _normalized_name(self):
normalized name from the file system path.
"""
stem = os.path.basename(str(self._path))
return self._name_from_stem(stem) or super()._normalized_name
return (
pass_none(Prepared.normalize)(self._name_from_stem(stem))
or super()._normalized_name
)

def _name_from_stem(self, stem):
name, ext = os.path.splitext(stem)
@staticmethod
def _name_from_stem(stem):
"""
>>> PathDistribution._name_from_stem('foo-3.0.egg-info')
'foo'
>>> PathDistribution._name_from_stem('CherryPy-3.0.dist-info')
'CherryPy'
>>> PathDistribution._name_from_stem('face.egg-info')
'face'
>>> PathDistribution._name_from_stem('foo.bar')
"""
filename, ext = os.path.splitext(stem)
if ext not in ('.dist-info', '.egg-info'):
return
name, sep, rest = stem.partition('-')
name, sep, rest = filename.partition('-')
return name


Expand Down Expand Up @@ -991,6 +1004,15 @@ def version(distribution_name):
return distribution(distribution_name).version


_unique = functools.partial(
unique_everseen,
key=operator.attrgetter('_normalized_name'),
)
"""
Wrapper for ``distributions`` to return unique distributions by name.
"""


def entry_points(**params) -> Union[EntryPoints, SelectableGroups]:
"""Return EntryPoint objects for all installed packages.
Expand All @@ -1008,10 +1030,8 @@ def entry_points(**params) -> Union[EntryPoints, SelectableGroups]:
:return: EntryPoints or SelectableGroups for all installed packages.
"""
norm_name = operator.attrgetter('_normalized_name')
unique = functools.partial(unique_everseen, key=norm_name)
eps = itertools.chain.from_iterable(
dist.entry_points for dist in unique(distributions())
dist.entry_points for dist in _unique(distributions())
)
return SelectableGroups.load(eps).select(**params)

Expand Down
16 changes: 16 additions & 0 deletions Lib/test/test_importlib/fixtures.py
Original file line number Diff line number Diff line change
Expand Up @@ -5,6 +5,7 @@
import pathlib
import tempfile
import textwrap
import functools
import contextlib

from test.support.os_helper import FS_NONASCII
Expand Down Expand Up @@ -296,3 +297,18 @@ def setUp(self):
# Add self.zip_name to the front of sys.path.
self.resources = contextlib.ExitStack()
self.addCleanup(self.resources.close)


def parameterize(*args_set):
"""Run test method with a series of parameters."""

def wrapper(func):
@functools.wraps(func)
def _inner(self):
for args in args_set:
with self.subTest(**args):
func(self, **args)

return _inner

return wrapper
91 changes: 49 additions & 42 deletions Lib/test/test_importlib/test_main.py
Original file line number Diff line number Diff line change
@@ -1,7 +1,6 @@
import re
import json
import pickle
import textwrap
import unittest
import warnings
import importlib.metadata
Expand All @@ -16,6 +15,7 @@
Distribution,
EntryPoint,
PackageNotFoundError,
_unique,
distributions,
entry_points,
metadata,
Expand Down Expand Up @@ -51,6 +51,14 @@ def test_package_not_found_mentions_metadata(self):
def test_new_style_classes(self):
self.assertIsInstance(Distribution, type)

@fixtures.parameterize(
dict(name=None),
dict(name=''),
)
def test_invalid_inputs_to_from_name(self, name):
with self.assertRaises(Exception):
Distribution.from_name(name)


class ImportTests(fixtures.DistInfoPkg, unittest.TestCase):
def test_import_nonexistent_module(self):
Expand Down Expand Up @@ -78,48 +86,50 @@ def test_resolve_without_attr(self):

class NameNormalizationTests(fixtures.OnSysPath, fixtures.SiteDir, unittest.TestCase):
@staticmethod
def pkg_with_dashes(site_dir):
def make_pkg(name):
"""
Create minimal metadata for a package with dashes
in the name (and thus underscores in the filename).
Create minimal metadata for a dist-info package with
the indicated name on the file system.
"""
metadata_dir = site_dir / 'my_pkg.dist-info'
metadata_dir.mkdir()
metadata = metadata_dir / 'METADATA'
with metadata.open('w', encoding='utf-8') as strm:
strm.write('Version: 1.0\n')
return 'my-pkg'
return {
f'{name}.dist-info': {
'METADATA': 'VERSION: 1.0\n',
},
}

def test_dashes_in_dist_name_found_as_underscores(self):
"""
For a package with a dash in the name, the dist-info metadata
uses underscores in the name. Ensure the metadata loads.
"""
pkg_name = self.pkg_with_dashes(self.site_dir)
assert version(pkg_name) == '1.0'

@staticmethod
def pkg_with_mixed_case(site_dir):
"""
Create minimal metadata for a package with mixed case
in the name.
"""
metadata_dir = site_dir / 'CherryPy.dist-info'
metadata_dir.mkdir()
metadata = metadata_dir / 'METADATA'
with metadata.open('w', encoding='utf-8') as strm:
strm.write('Version: 1.0\n')
return 'CherryPy'
fixtures.build_files(self.make_pkg('my_pkg'), self.site_dir)
assert version('my-pkg') == '1.0'

def test_dist_name_found_as_any_case(self):
"""
Ensure the metadata loads when queried with any case.
"""
pkg_name = self.pkg_with_mixed_case(self.site_dir)
pkg_name = 'CherryPy'
fixtures.build_files(self.make_pkg(pkg_name), self.site_dir)
assert version(pkg_name) == '1.0'
assert version(pkg_name.lower()) == '1.0'
assert version(pkg_name.upper()) == '1.0'

def test_unique_distributions(self):
"""
Two distributions varying only by non-normalized name on
the file system should resolve as the same.
"""
fixtures.build_files(self.make_pkg('abc'), self.site_dir)
before = list(_unique(distributions()))

alt_site_dir = self.fixtures.enter_context(fixtures.tempdir())
self.fixtures.enter_context(self.add_sys_path(alt_site_dir))
fixtures.build_files(self.make_pkg('ABC'), alt_site_dir)
after = list(_unique(distributions()))

assert len(after) == len(before)


class NonASCIITests(fixtures.OnSysPath, fixtures.SiteDir, unittest.TestCase):
@staticmethod
Expand All @@ -128,11 +138,12 @@ def pkg_with_non_ascii_description(site_dir):
Create minimal metadata for a package with non-ASCII in
the description.
"""
metadata_dir = site_dir / 'portend.dist-info'
metadata_dir.mkdir()
metadata = metadata_dir / 'METADATA'
with metadata.open('w', encoding='utf-8') as fp:
fp.write('Description: pôrˈtend')
contents = {
'portend.dist-info': {
'METADATA': 'Description: pôrˈtend',
},
}
fixtures.build_files(contents, site_dir)
return 'portend'

@staticmethod
Expand All @@ -141,19 +152,15 @@ def pkg_with_non_ascii_description_egg_info(site_dir):
Create minimal metadata for an egg-info package with
non-ASCII in the description.
"""
metadata_dir = site_dir / 'portend.dist-info'
metadata_dir.mkdir()
metadata = metadata_dir / 'METADATA'
with metadata.open('w', encoding='utf-8') as fp:
fp.write(
textwrap.dedent(
"""
contents = {
'portend.dist-info': {
'METADATA': """
Name: portend
pôrˈtend
"""
).strip()
)
pôrˈtend""",
},
}
fixtures.build_files(contents, site_dir)
return 'portend'

def test_metadata_loads(self):
Expand Down
6 changes: 3 additions & 3 deletions Lib/test/test_importlib/test_metadata_api.py
Original file line number Diff line number Diff line change
Expand Up @@ -89,15 +89,15 @@ def test_entry_points_distribution(self):
self.assertIn(ep.dist.name, ('distinfo-pkg', 'egginfo-pkg'))
self.assertEqual(ep.dist.version, "1.0.0")

def test_entry_points_unique_packages(self):
def test_entry_points_unique_packages_normalized(self):
"""
Entry points should only be exposed for the first package
on sys.path with a given name.
on sys.path with a given name (even when normalized).
"""
alt_site_dir = self.fixtures.enter_context(fixtures.tempdir())
self.fixtures.enter_context(self.add_sys_path(alt_site_dir))
alt_pkg = {
"distinfo_pkg-1.1.0.dist-info": {
"DistInfo_pkg-1.1.0.dist-info": {
"METADATA": """
Name: distinfo-pkg
Version: 1.1.0
Expand Down
Original file line number Diff line number Diff line change
@@ -0,0 +1,2 @@
Now raise ``ValueError`` when ``None`` or an empty string are passed to
``Distribution.from_name`` (and other callers).

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