Display a user-friendly exception when entry-point is invalid

Author: abravalheri

setuptools/_entry_points.py

@@ -2,6 +2,7 @@
 import operator
 import itertools
 
+from .errors import OptionError
 from .extern.jaraco.text import yield_lines
 from .extern.jaraco.functools import pass_none
 from ._importlib import metadata
@@ -14,7 +15,14 @@ def ensure_valid(ep):
     Exercise one of the dynamic properties to trigger
     the pattern match.
     """
-    ep.extras
+    try:
+        ep.extras
+    except AttributeError as ex:
+        msg = (
+            f"Problems to parse {ep}.\nPlease ensure entry-point follows the spec: "
+            "https://packaging.python.org/en/latest/specifications/entry-points/"
+        )
+        raise OptionError(msg) from ex
 
 
 def load_group(value, group):