Line too long: String in return annotation

[intgr]

To Reproduce

Given input:

class ThisIsTrulyUnreasonablyExtremelyLongClassName:
    pass


def frobnicate() -> "ThisIsTrulyUnreasonablyExtremelyLongClassName | list[ThisIsTrulyUnreasonablyExtremelyLongClassName]":
    pass

Black does not split the long type hint of the function return type

Even if I explicitly attempt to split the string:

def frobnicate() -> "ThisIsTrulyUnreasonablyExtremelyLongClassName | " \
                    "list[ThisIsTrulyUnreasonablyExtremelyLongClassName]":
    pass

then Black collapses it back together :(

def frobnicate() -> "ThisIsTrulyUnreasonablyExtremelyLongClassName | " "list[ThisIsTrulyUnreasonablyExtremelyLongClassName]":
    pass

Workaround

Only by parenthesizing the type hint I can convince Black to keep it reasonable.

def frobnicate() -> (
    "ThisIsTrulyUnreasonablyExtremelyLongClassName | "
    "list[ThisIsTrulyUnreasonablyExtremelyLongClassName]"
):
    pass

Environment

• Black's version: 21.12b0
• OS and Python version: macOS, Python 3.10.1

[ichard26]

Can confirm this exists on main as of commit e9f520c even with experimental string processing enabled. Thank you for the report!

[jakkdl]

This should be reopened, or open a new issue, as it didn't get fixed by #2990 other than the specific case of having no parameters. See the test case added in #3916: https://github.com/jakkdl/black/blob/be48f7bee25efccdf6957a3c37dcce8a82301819/tests/data/preview/return_annotation_brackets_string.py

[JelleZijlstra]

Could you open a new issue?