Merge pull request #281 from python/bugfix/280-unique-distributions

Restrict to unique distributions in entry points

Author: jaraco

.coveragerc

@@ -3,6 +3,7 @@ omit =
 	*/.tox/*
 	tests/*
 	prepare/*
+	*/_itertools.py
 
 [report]
 show_missing = True

CHANGES.rst

@@ -1,3 +1,9 @@
+v3.5.0
+======
+
+* #280: ``entry_points`` now only returns entry points for
+  unique distributions (by name).
+
 v3.4.0
 ======
 

importlib_metadata/__init__.py

@@ -19,6 +19,8 @@
     Protocol,
 )
 
+from ._itertools import unique_everseen
+
 from configparser import ConfigParser
 from contextlib import suppress
 from importlib import import_module
@@ -646,7 +648,10 @@ def entry_points():
 
     :return: EntryPoint objects for all installed packages.
     """
-    eps = itertools.chain.from_iterable(dist.entry_points for dist in distributions())
+    unique = functools.partial(unique_everseen, key=operator.attrgetter('name'))
+    eps = itertools.chain.from_iterable(
+        dist.entry_points for dist in unique(distributions())
+    )
     by_group = operator.attrgetter('group')
     ordered = sorted(eps, key=by_group)
     grouped = itertools.groupby(ordered, by_group)

importlib_metadata/_itertools.py

@@ -0,0 +1,19 @@
+from itertools import filterfalse
+
+
+def unique_everseen(iterable, key=None):
+    "List unique elements, preserving order. Remember all elements ever seen."
+    # unique_everseen('AAAABBBCCDAABBB') --> A B C D
+    # unique_everseen('ABBCcAD', str.lower) --> A B C D
+    seen = set()
+    seen_add = seen.add
+    if key is None:
+        for element in filterfalse(seen.__contains__, iterable):
+            seen_add(element)
+            yield element
+    else:
+        for element in iterable:
+            k = key(element)
+            if k not in seen:
+                seen_add(k)
+                yield element

tests/test_api.py

@@ -76,6 +76,34 @@ 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):
+        """
+        Entry points should only be exposed for the first package
+        on sys.path with a given name.
+        """
+        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": {
+                "METADATA": """
+                Name: distinfo-pkg
+                Version: 1.1.0
+                """,
+                "entry_points.txt": """
+                [entries]
+                main = mod:altmain
+            """,
+            },
+        }
+        fixtures.build_files(alt_pkg, alt_site_dir)
+        entries = dict(entry_points()['entries'])
+        assert not any(
+            ep.dist.name == 'distinfo-pkg' and ep.dist.version == '1.0.0'
+            for ep in entries.values()
+        )
+        # ns:sub doesn't exist in alt_pkg
+        assert 'ns:sub' not in entries
+
     def test_metadata_for_this_package(self):
         md = metadata('egginfo-pkg')
         assert md['author'] == 'Steven Ma'

tox.ini

@@ -39,6 +39,7 @@ deps =
 	ipython
 commands =
 	python -m timeit -s 'import importlib_metadata' -- 'importlib_metadata.distribution("ipython")'
+	python -m timeit -s 'import importlib_metadata' -- 'importlib_metadata.entry_points()'
 
 [testenv:release]
 skip_install = True