Merge pull request #498 from python/feature/entry-points-disallow-dis…

…t-match

Disallow passing of 'dist' to EntryPoints.select.

importlib_metadata/__init__.py

@@ -227,9 +227,26 @@ def matches(self, **params):
         >>> ep.matches(attr='bong')
         True
         """
+        self._disallow_dist(params)
         attrs = (getattr(self, param) for param in params)
         return all(map(operator.eq, params.values(), attrs))
 
+    @staticmethod
+    def _disallow_dist(params):
+        """
+        Querying by dist is not allowed (dist objects are not comparable).
+        >>> EntryPoint(name='fan', value='fav', group='fag').matches(dist='foo')
+        Traceback (most recent call last):
+        ...
+        ValueError: "dist" is not suitable for matching...
+        """
+        if "dist" in params:
+            raise ValueError(
+                '"dist" is not suitable for matching. '
+                "Instead, use Distribution.entry_points.select() on a "
+                "located distribution."
+            )
+
     def _key(self):
         return self.name, self.value, self.group
 

newsfragments/+29a322e3.feature.rst

@@ -0,0 +1 @@
+Disallow passing of 'dist' to EntryPoints.select.