From c956734d7af83ad31f847d31d0d26df087add9a4 Mon Sep 17 00:00:00 2001 From: Ethan Furman Date: Fri, 11 Jun 2021 02:44:43 -0700 Subject: bpo-44242: [Enum] improve error messages (GH-26669) --- Lib/enum.py | 37 +++++++++++++++++++++++++------------ Lib/test/test_enum.py | 12 +++++------- 2 files changed, 30 insertions(+), 19 deletions(-) diff --git a/Lib/enum.py b/Lib/enum.py index 5548130..0c6d8c1 100644 --- a/Lib/enum.py +++ b/Lib/enum.py @@ -1,5 +1,7 @@ import sys from types import MappingProxyType, DynamicClassAttribute +from operator import or_ as _or_ +from functools import reduce from builtins import property as _bltin_property, bin as _bltin_bin @@ -97,6 +99,9 @@ def _iter_bits_lsb(num): yield b num ^= b +def show_flag_values(value): + return list(_iter_bits_lsb(value)) + def bin(num, max_bits=None): """ Like built-in bin(), except negative values are represented in @@ -1601,14 +1606,16 @@ class verify: else: raise Exception('verify: unknown type %r' % enum_type) if missing: - raise ValueError('invalid %s %r: missing values %s' % ( + raise ValueError(('invalid %s %r: missing values %s' % ( enum_type, cls_name, ', '.join((str(m) for m in missing))) - ) + )[:256]) + # limit max length to protect against DOS attacks elif check is NAMED_FLAGS: # examine each alias and check for unnamed flags member_names = enumeration._member_names_ member_values = [m.value for m in enumeration] - missing = [] + missing_names = [] + missing_value = 0 for name, alias in enumeration._member_map_.items(): if name in member_names: # not an alias @@ -1616,16 +1623,22 @@ class verify: values = list(_iter_bits_lsb(alias.value)) missed = [v for v in values if v not in member_values] if missed: - plural = ('', 's')[len(missed) > 1] - a = ('a ', '')[len(missed) > 1] - missing.append('%r is missing %snamed flag%s for value%s %s' % ( - name, a, plural, plural, - ', '.join(str(v) for v in missed) - )) - if missing: + missing_names.append(name) + missing_value |= reduce(_or_, missed) + if missing_names: + if len(missing_names) == 1: + alias = 'alias %s is missing' % missing_names[0] + else: + alias = 'aliases %s and %s are missing' % ( + ', '.join(missing_names[:-1]), missing_names[-1] + ) + if _is_single_bit(missing_value): + value = 'value 0x%x' % missing_value + else: + value = 'combined values of 0x%x' % missing_value raise ValueError( - 'invalid Flag %r: %s' - % (cls_name, '; '.join(missing)) + 'invalid Flag %r: %s %s [use `enum.show_flag_values(value)` for details]' + % (cls_name, alias, value) ) return enumeration diff --git a/Lib/test/test_enum.py b/Lib/test/test_enum.py index 22a829d..956b834 100644 --- a/Lib/test/test_enum.py +++ b/Lib/test/test_enum.py @@ -2166,9 +2166,6 @@ class TestEnum(unittest.TestCase): self._valid = True @classmethod def _missing_(cls, value): - # encountered an unknown value! - # Luckily I'm a LenientStrEnum, so I won't crash just yet. - # You might want to add a new case though. unknown = cls._member_type_.__new__(cls, value) unknown._valid = False unknown._name_ = value.upper() @@ -3594,7 +3591,7 @@ class TestVerify(unittest.TestCase): self.assertEqual(Bizarre.d.value, 6) with self.assertRaisesRegex( ValueError, - "invalid Flag 'Bizarre': 'b' is missing named flags for values 1, 2; 'd' is missing a named flag for value 2", + "invalid Flag 'Bizarre': aliases b and d are missing combined values of 0x3 .use `enum.show_flag_values.value.` for details.", ): @verify(NAMED_FLAGS) class Bizarre(Flag): @@ -3602,6 +3599,7 @@ class TestVerify(unittest.TestCase): c = 4 d = 6 # + self.assertEqual(enum.show_flag_values(3), [1, 2]) class Bizarre(IntFlag): b = 3 c = 4 @@ -3612,13 +3610,13 @@ class TestVerify(unittest.TestCase): self.assertEqual(Bizarre.d.value, 6) with self.assertRaisesRegex( ValueError, - "invalid Flag 'Bizarre': 'b' is missing named flags for values 1, 2; 'd' is missing a named flag for value 2", + "invalid Flag 'Bizarre': alias d is missing value 0x2 .use `enum.show_flag_values.value.` for details.", ): @verify(NAMED_FLAGS) class Bizarre(IntFlag): - b = 3 c = 4 d = 6 + self.assertEqual(enum.show_flag_values(2), [2]) def test_unique_clean(self): @verify(UNIQUE) @@ -3885,7 +3883,7 @@ class TestStdLib(unittest.TestCase): class MiscTestCase(unittest.TestCase): def test__all__(self): - support.check__all__(self, enum, not_exported={'bin'}) + support.check__all__(self, enum, not_exported={'bin', 'show_flag_values'}) # These are unordered here on purpose to ensure that declaration order -- cgit v0.12