Use X | Y union syntax in error messages on recent Python versions #15082
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JukkaL
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Apr 24, 2023
This should fix #15082: If the python version is set to 3.10 or later union error reports are going to be displayed using the `X | Y` syntax. If None is found in a union it is shown as the last element in order to improve visibility (`Union[bool, None, str]` becomes `"bool | str | None"`. To achieve this an option `use_or_syntax()` is created that is set to true if the python version is 3.10 or later. For testing a hidden flag --force-union-syntax is used that sets the option to false.
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As a follow-up to #15070, display union types using the new
X | Ysyntax in error messages when targeting Python 3.10 or later.Examples:
Union[int, str], displayint | str.Optional[str], displaystr | NoneIf there is
Nonein a union type, perhaps always display theNoneas the final item. This way we'd never show a type likeNone | str(even if type inference would produce this internal representation), since it's not idiomatic.Generalize the implementation technique used in #15070, which added a version check for using
list[x]instead ofList[x]in error messages on Python 3.9 and later. In particular, use the hidden command line option in tests to always use the old syntax, so that tests will run consistently. Add specific test cases that enable theX | Ysyntax only in the new tests that test this syntax.The text was updated successfully, but these errors were encountered: