Merge branch 'maint/2.x'

CHANGES.rst

@@ -1,3 +1,13 @@
+v3.1.1
+======
+
+v2.1.1
+======
+
+* #261: Restored compatibility for package discovery for
+  metadata without version in the name and for legacy
+  eggs.
+
 v3.1.0
 ======
 

importlib_metadata/__init__.py

@@ -448,47 +448,29 @@ def zip_children(self):
 
         return dict.fromkeys(child.split(posixpath.sep, 1)[0] for child in names)
 
-    def is_egg(self, search):
-        base = self.base
+    def search(self, name):
         return (
-            base == search.versionless_egg_name
-            or base.startswith(search.prefix)
-            and base.endswith('.egg')
+            self.joinpath(child)
+            for child in self.children()
+            if name.matches(child, self.base)
         )
 
-    def search(self, name):
-        for child in self.children():
-            n_low = child.lower()
-            if (
-                n_low in name.exact_matches
-                or n_low.replace('.', '_').startswith(name.prefix)
-                and n_low.endswith(name.suffixes)
-                # legacy case:
-                or self.is_egg(name)
-                and n_low == 'egg-info'
-            ):
-                yield self.joinpath(child)
-
 
 class Prepared:
     """
     A prepared search for metadata on a possibly-named package.
     """
 
-    normalized = ''
-    prefix = ''
+    normalized = None
     suffixes = '.dist-info', '.egg-info'
     exact_matches = [''][:0]
-    versionless_egg_name = ''
 
     def __init__(self, name):
         self.name = name
         if name is None:
             return
         self.normalized = self.normalize(name)
-        self.prefix = self.normalized + '-'
         self.exact_matches = [self.normalized + suffix for suffix in self.suffixes]
-        self.versionless_egg_name = self.normalized + '.egg'
 
     @staticmethod
     def normalize(name):
@@ -497,6 +479,37 @@ def normalize(name):
         """
         return re.sub(r"[-_.]+", "-", name).lower().replace('-', '_')
 
+    @staticmethod
+    def legacy_normalize(name):
+        """
+        Normalize the package name as found in the convention in
+        older packaging tools versions and specs.
+        """
+        return name.lower().replace('-', '_')
+
+    def matches(self, cand, base):
+        low = cand.lower()
+        pre, ext = os.path.splitext(low)
+        name, sep, rest = pre.partition('-')
+        return (
+            low in self.exact_matches
+            or ext in self.suffixes
+            and (not self.normalized or name.replace('.', '_') == self.normalized)
+            # legacy case:
+            or self.is_egg(base)
+            and low == 'egg-info'
+        )
+
+    def is_egg(self, base):
+        normalized = self.legacy_normalize(self.name or '')
+        prefix = normalized + '-' if normalized else ''
+        versionless_egg_name = normalized + '.egg' if self.name else ''
+        return (
+            base == versionless_egg_name
+            or base.startswith(prefix)
+            and base.endswith('.egg')
+        )
+
 
 @install
 class MetadataPathFinder(NullFinder, DistributionFinder):

tests/fixtures.py

@@ -128,6 +128,12 @@ class DistInfoPkgWithDotLegacy(OnSysPath, SiteDir):
                 Version: 1.0.0
                 """,
         },
+        "pkg.lot.egg-info": {
+            "METADATA": """
+                Name: pkg.lot
+                Version: 1.0.0
+                """,
+        },
     }
 
     def setUp(self):

tests/test_api.py

@@ -45,6 +45,13 @@ def test_name_normalization(self):
             with self.subTest(name):
                 assert distribution(name).metadata['Name'] == 'pkg.dot'
 
+    def test_prefix_not_matched(self):
+        prefixes = 'p', 'pkg', 'pkg.'
+        for prefix in prefixes:
+            with self.subTest(prefix):
+                with self.assertRaises(PackageNotFoundError):
+                    distribution(prefix)
+
     def test_for_top_level(self):
         self.assertEqual(
             distribution('egginfo-pkg').read_text('top_level.txt').strip(), 'mod'
@@ -160,6 +167,12 @@ def test_name_normalization(self):
             with self.subTest(name):
                 assert distribution(name).metadata['Name'] == 'pkg.dot'
 
+    def test_name_normalization_versionless_egg_info(self):
+        names = 'pkg.lot', 'pkg_lot', 'pkg-lot', 'pkg..lot', 'Pkg.Lot'
+        for name in names:
+            with self.subTest(name):
+                assert distribution(name).metadata['Name'] == 'pkg.lot'
+
 
 class OffSysPathTests(fixtures.DistInfoPkgOffPath, unittest.TestCase):
     def test_find_distributions_specified_path(self):