bpo-39728: Fixed after review

Andrey Darascheka · Andrey Darascheka · commit 72eb2c4fe3ac · 2020-02-24T13:44:58.000+03:00
diff --git a/Lib/enum.py b/Lib/enum.py
@@ -585,6 +585,7 @@ def __new__(cls, value):
                         'error in %s._missing_: returned %r instead of None or a valid member'
                         % (cls.__name__, result)
                         )
+                exc.__context__ = ve_exc
             raise exc
 
     def _generate_next_value_(name, start, count, last_values):
diff --git a/Lib/test/test_enum.py b/Lib/test/test_enum.py
@@ -1778,10 +1778,18 @@ def _missing_(cls, item):
         self.assertIs(Color('three'), Color.blue)
         with self.assertRaises(ValueError):
             Color(7)
-        with self.assertRaises(TypeError):
+        try:
             Color('bad return')
-        with self.assertRaises(ZeroDivisionError):
+        except TypeError as exc:
+            self.assertTrue(isinstance(exc.__context__, ValueError))
+        else:
+            raise Exception('Exception not raised.')
+        try:
             Color('error out')
+        except ZeroDivisionError as exc:
+            self.assertTrue(not exc.__context__)
+        else:
+            raise Exception('Exception not raised.')
 
     def test_multiple_mixin(self):
         class MaxMixin:

Original file line number	Diff line number	Diff line change
`@@ -585,6 +585,7 @@ def __new__(cls, value):`
`585`	`585`	`'error in %s._missing_: returned %r instead of None or a valid member'`
`586`	`586`	`% (cls.__name__, result)`
`587`	`587`	`)`
	`588`	`+ exc.__context__ = ve_exc`
`588`	`589`	`raise exc`
`589`	`590`
`590`	`591`	`def _generate_next_value_(name, start, count, last_values):`