Merge branch 'feature/refactor-fewer-finders' into 'master'

A simpler implementation with fewer finders

Closes #60 and #59

See merge request python-devs/importlib_metadata!60

Author: warsaw

importlib_metadata/_hooks.py

@@ -11,17 +11,21 @@
 
 if sys.version_info >= (3,):  # pragma: nocover
     from contextlib import suppress
-    from pathlib import Path
 else:  # pragma: nocover
     from contextlib2 import suppress  # noqa
     from itertools import imap as map  # type: ignore
-    from pathlib2 import Path
 
     FileNotFoundError = IOError, OSError
     NotADirectoryError = IOError, OSError
     __metaclass__ = type
 
 
+if sys.version_info > (3, 5):  # pragma: nocover
+    from pathlib import Path
+else:  # pragma: nocover
+    from pathlib2 import Path
+
+
 def install(cls):
     """Class decorator for installation on sys.meta_path."""
     sys.meta_path.append(cls())
@@ -46,12 +50,14 @@ def find_spec(*args, **kwargs):
     find_module = find_spec
 
 
-class MetadataPathBaseFinder(NullFinder):
+@install
+class MetadataPathFinder(NullFinder):
     """A degenerate finder for distribution packages on the file system.
 
     This finder supplies only a find_distributions() method for versions
     of Python that do not have a PathFinder find_distributions().
     """
+    search_template = r'{pattern}(-.*)?\.(dist|egg)-info'
 
     def find_distributions(self, name=None, path=None):
         """Return an iterable of all Distribution instances capable of
@@ -72,9 +78,15 @@ def _search_paths(cls, pattern, paths):
         """
         return itertools.chain.from_iterable(
             cls._search_path(path, pattern)
-            for path in map(Path, paths)
+            for path in map(cls._switch_path, paths)
             )
 
+    @staticmethod
+    def _switch_path(path):
+        with suppress(Exception):
+            return zipp.Path(path)
+        return Path(path)
+
     @classmethod
     def _predicate(cls, pattern, root, item):
         return re.match(pattern, str(item.name), flags=re.IGNORECASE)
@@ -89,82 +101,15 @@ def _search_path(cls, root, pattern):
                 if cls._predicate(matcher, root, item))
 
 
-@install
-class MetadataPathFinder(MetadataPathBaseFinder):
-    search_template = r'{pattern}(-.*)?\.(dist|egg)-info'
-
-
-@install
-class MetadataPathEggInfoFileFinder(MetadataPathBaseFinder):
-    search_template = r'{pattern}(-.*)?\.egg-info'
-
-    @classmethod
-    def _predicate(cls, pattern, root, item):
-        return (
-            (root / item).is_file() and
-            re.match(pattern, str(item.name), flags=re.IGNORECASE))
-
-
 class PathDistribution(Distribution):
     def __init__(self, path):
         """Construct a distribution from a path to the metadata directory."""
         self._path = path
 
     def read_text(self, filename):
-        with suppress(FileNotFoundError, NotADirectoryError):
-            with self._path.joinpath(filename).open(encoding='utf-8') as fp:
-                return fp.read()
-        return None
+        with suppress(FileNotFoundError, NotADirectoryError, KeyError):
+            return self._path.joinpath(filename).read_text(encoding='utf-8')
     read_text.__doc__ = Distribution.read_text.__doc__
 
     def locate_file(self, path):
         return self._path.parent / path
-
-
-@install
-class WheelMetadataFinder(NullFinder):
-    """A degenerate finder for distribution packages in wheels.
-
-    This finder supplies only a find_distributions() method for versions
-    of Python that do not have a PathFinder find_distributions().
-    """
-    search_template = r'{pattern}(-.*)?\.whl'
-
-    def find_distributions(self, name=None, path=None):
-        """Return an iterable of all Distribution instances capable of
-        loading the metadata for packages matching the name
-        (or all names if not supplied) along the paths in the list
-        of directories ``path`` (defaults to sys.path).
-        """
-        if path is None:
-            path = sys.path
-        pattern = '.*' if name is None else re.escape(name)
-        found = self._search_paths(pattern, path)
-        return map(WheelDistribution, found)
-
-    @classmethod
-    def _search_paths(cls, pattern, paths):
-        return (
-            path
-            for path in map(Path, paths)
-            if re.match(
-                cls.search_template.format(pattern=pattern),
-                str(path.name),
-                flags=re.IGNORECASE,
-                )
-            )
-
-
-class WheelDistribution(Distribution):
-    def __init__(self, archive):
-        self._archive = zipp.Path(archive)
-        name, version = archive.name.split('-')[0:2]
-        self._dist_info = '{}-{}.dist-info'.format(name, version)
-
-    def read_text(self, filename):
-        target = self._archive / self._dist_info / filename
-        return target.read_text() if target.exists() else None
-    read_text.__doc__ = Distribution.read_text.__doc__
-
-    def locate_file(self, path):
-        return self._archive / path

importlib_metadata/api.py

@@ -15,13 +15,16 @@
 from itertools import starmap
 
 if sys.version_info > (3,):  # pragma: nocover
-    import pathlib
     from configparser import ConfigParser
 else:  # pragma: nocover
-    import pathlib2 as pathlib
     from backports.configparser import ConfigParser
     from itertools import imap as map  # type: ignore
 
+if sys.version_info > (3, 5):  # pragma: nocover
+    import pathlib
+else:  # pragma: nocover
+    import pathlib2 as pathlib
+
 try:
     BaseClass = ModuleNotFoundError
 except NameError:                                 # pragma: nocover

importlib_metadata/docs/using.rst

@@ -18,17 +18,10 @@ Python's ``site-packages`` directory via tools such as `pip
 <https://pypi.org/project/pip/>`_.  Specifically,
 it means a package with either a discoverable ``dist-info`` or ``egg-info``
 directory, and metadata defined by `PEP 566`_ or its older specifications.
-By default, package metadata can live on the file system or in wheels on
+By default, package metadata can live on the file system or in zip archives on
 ``sys.path``.  Through an extension mechanism, the metadata can live almost
 anywhere.
 
-.. note::  Although this package supports loading metadata from wheels
-   on ``sys.path``, that support is provisional and does not serve to
-   contravene the `PEP 427 directive
-   <https://www.python.org/dev/peps/pep-0427/#is-it-possible-to-import-python-code-directly-from-a-wheel-file>`_,
-   which states that relying on this format is discouraged, and use is
-   at your own risk.
-
 
 Overview
 ========

importlib_metadata/tests/test_main.py

@@ -32,8 +32,6 @@ def test_for_name_does_not_exist(self):
     def test_new_style_classes(self):
         self.assertIsInstance(Distribution, type)
         self.assertIsInstance(_hooks.MetadataPathFinder, type)
-        self.assertIsInstance(_hooks.WheelMetadataFinder, type)
-        self.assertIsInstance(_hooks.WheelDistribution, type)
 
 
 class ImportTests(fixtures.DistInfoPkg, unittest.TestCase):

setup.cfg

@@ -17,8 +17,8 @@ classifiers =
 [options]
 python_requires = >=2.7,!=3.0,!=3.1,!=3.2,!=3.3
 install_requires =
-    zipp>=0.3.2
-    pathlib2; python_version < '3'
+    zipp>=0.5
+    pathlib2; python_version=='3.4.*' or python_version < '3'
     contextlib2; python_version < '3'
     configparser; python_version < '3'
 packages = find: