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-rw-r--r--Lib/enum.py2
-rw-r--r--Lib/test/test_enum.py19
-rw-r--r--Misc/ACKS1
-rw-r--r--Misc/NEWS.d/next/Library/2020-02-24-10-58-34.bpo-39728.kOOaHn.rst1
4 files changed, 21 insertions, 2 deletions
diff --git a/Lib/enum.py b/Lib/enum.py
index da5a31f..ebadd9f 100644
--- a/Lib/enum.py
+++ b/Lib/enum.py
@@ -628,7 +628,7 @@ class Enum(metaclass=EnumMeta):
@classmethod
def _missing_(cls, value):
- raise ValueError("%r is not a valid %s" % (value, cls.__qualname__))
+ return None
def __repr__(self):
return "<%s.%s: %r>" % (
diff --git a/Lib/test/test_enum.py b/Lib/test/test_enum.py
index 6f54716..0e6b1b1 100644
--- a/Lib/test/test_enum.py
+++ b/Lib/test/test_enum.py
@@ -1832,6 +1832,18 @@ class TestEnum(unittest.TestCase):
third = auto()
self.assertEqual([Dupes.first, Dupes.second, Dupes.third], list(Dupes))
+ def test_default_missing(self):
+ class Color(Enum):
+ RED = 1
+ GREEN = 2
+ BLUE = 3
+ try:
+ Color(7)
+ except ValueError as exc:
+ self.assertTrue(exc.__context__ is None)
+ else:
+ raise Exception('Exception not raised.')
+
def test_missing(self):
class Color(Enum):
red = 1
@@ -1850,7 +1862,12 @@ class TestEnum(unittest.TestCase):
# trigger not found
return None
self.assertIs(Color('three'), Color.blue)
- self.assertRaises(ValueError, Color, 7)
+ try:
+ Color(7)
+ except ValueError as exc:
+ self.assertTrue(exc.__context__ is None)
+ else:
+ raise Exception('Exception not raised.')
try:
Color('bad return')
except TypeError as exc:
diff --git a/Misc/ACKS b/Misc/ACKS
index 2a180eb..5e0953a 100644
--- a/Misc/ACKS
+++ b/Misc/ACKS
@@ -432,6 +432,7 @@ Marcos Donolo
Dima Dorfman
Yves Dorfsman
Michael Dorman
+Andrey Doroschenko
Steve Dower
Allen Downey
Cesar Douady
diff --git a/Misc/NEWS.d/next/Library/2020-02-24-10-58-34.bpo-39728.kOOaHn.rst b/Misc/NEWS.d/next/Library/2020-02-24-10-58-34.bpo-39728.kOOaHn.rst
new file mode 100644
index 0000000..beb2016
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2020-02-24-10-58-34.bpo-39728.kOOaHn.rst
@@ -0,0 +1 @@
+fix default `_missing_` so a duplicate `ValueError` is not set as the `__context__` of the original `ValueError`