Encountered yet another breaking change for enums. There are two problems here:

• CONFORM doesn't "conform" to members that are partially unsupported
• CONFORM does not match the previous behavior for Flag. It used to be more similar to STRICT, but STRICT also doesn't allow partially unsupported members, while Flag in 3.10 did.

Example to reproduce:

importenumclassSkipFlag(enum.Flag):A=1B=2C=4|Bprint(SkipFlag.Cin (SkipFlag.A|SkipFlag.C))classSkipIntFlag(enum.IntFlag):A=1B=2C=4|Bprint(SkipIntFlag.Cin (SkipIntFlag.A|SkipIntFlag.C))print(SkipIntFlag(42).value)print(SkipFlag(42).value)

In Python 3.10.6, this code outputs:

TrueTrue42Traceback (most recent call last):...ValueError: 42 is not a valid SkipFlag

In Python 3.11.2:

FalseTrue422

Having such members as C is useful to create a flags that are distinct from B but always implies B.

In a previous comment bug report it was stated that the previous behavior of Flag was CONFORM:

Actually, won't need a deprecation period, since the proper default forFlag isCONFORM as that matches previous behavior.

Originally posted by@ethanfurman in#96865 (comment)

Clearly this is incorrect. The previous behavior was more similar to STRICT, but there appears to be no precise equivalent in Python 3.11 to the old behavior. Using STRICT in Python 3.11,SkipFlag.A | SkipFlag.C would fail to be created completely.

Linked PRs

• gh-103365: [Enum] STRICT boundary corrections #103494
• [3.11] gh-103365: [Enum] STRICT boundary corrections (GH-103494) #103513