[Fix error] Syntax Error Bug encountered with pyupgrade and multi-line Union #23207
Description
Just encountered the request for bug report when running ruff:
error: Fix introduced a syntax error. Reverting all changes.
This indicates a bug in Ruff. If you could open an issue at:
I was able to narrow it down to a pretty small reproducer.
$ tree .
.
├── main.py
└── pyproject.toml# pyproject.toml
[project]
name = "ruffbug"
version = "0.1.0"
requires-python = ">=3.10"
[tool.ruff]
line-length = 88
target-version = "py310"
fix = true
[tool.ruff.lint]
select = ["UP"]# main.py
from __future__ import annotations
from typing import TYPE_CHECKING
if TYPE_CHECKING:
from typing import Literal, TypeAlias, Union
LongLiterals: TypeAlias = Union[
Literal["LongLiteralNumberOne"]
| Literal["LongLiteralNumberTwo"]
| Literal["LongLiteralNumberThree"]
]$ uv run ruff check main.py --fix
error: Fix introduced a syntax error. Reverting all changes.
This indicates a bug in Ruff. If you could open an issue at:
https://github.com/astral-sh/ruff/issues/new?title=%5BFix%20error%5D
...quoting the contents of `main.py`, the rule codes UP007, along with the `pyproject.toml` settings and executed command, we'd be very appreciative!
UP007 Use `X | Y` for type annotations
--> main.py:8:31
|
6 | from typing import Literal, TypeAlias, Union
7 |
8 | LongLiterals: TypeAlias = Union[
| _______________________________^
9 | | Literal["LongLiteralNumberOne"]
10 | | | Literal["LongLiteralNumberTwo"]
11 | | | Literal["LongLiteralNumberThree"]
12 | | ]
| |_____^
|
help: Convert to `X | Y`
Found 1 error.
[*] 1 fixable with the `--fix` option.importantly: If I get rid of that third Literal["LongLiteralNumberThree"] (such that formatting would cause the union to fit on a single line), then a round of ruff format and ruff check work fine. It seems to only have difficulty with the multi-line union