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INTERNAL ERROR crash; syntax error in log #5187
Description
Describe the bug
Given particular inputs, Black crashes with an INTERNAL ERROR that I have not made sense of.
To Reproduce
Put this code in bug.py:
with open("bug.txt", "r", encoding="utf-8") as fh1:
pass
# fmt: off
# fmt: on
# xxx
# fmt: off
# fmt: on
with open("bug.txt", "r", encoding="utf-8") as fh2:
pass
def fn(str: str) -> float:
match str:
case _:
passAnd run black bug.py.
The resulting error is:
error: cannot format bug.py: INTERNAL ERROR: Black 26.5.2.dev29+gb74b23013 on Python (CPython) 3.14.5 produced invalid code: unindent does not match any outer indentation level (<unknown>, line 10). Please report a bug on https://github.com/psf/black/issues. This invalid output might be helpful: /run/user/1000/tmpdir/blk_tnip9iro.log
Oh no! 💥 💔 💥
1 file failed to reformat.
The .log file reads
File "/home/lukeshu/Projects/sbc-harness/sbc-harness-hardware/build-aux/venv/lib/python3.14/site-packages/black/__init__.py", line 1652, in assert_equivalent
dst_ast = parse_ast(dst)
File "/home/lukeshu/Projects/sbc-harness/sbc-harness-hardware/build-aux/venv/lib/python3.14/site-packages/black/parsing.py", line 162, in parse_ast
raise SyntaxError(first_error)
with open("bug.txt", "r", encoding="utf-8") as fh1:
pass
# fmt: off
# fmt: on
# xxx
# fmt: off
# fmt: on
with open("bug.txt", "r", encoding="utf-8") as fh2:
pass
def fn(str: str) -> float:
match str:
case _:
pass
Expected behavior
I expected Black to not crash.
Environment
Observed with both
$ black --version
black, 26.5.1 (compiled: no)
Python (CPython) 3.14.5
and
(venv) $ black --version
black, 26.5.2.dev29+gb74b23013 (compiled: no)
Python (CPython) 3.14.5
On Parabola GNU/Linux-libre (like Arch Linux).
Additional context
Running python bug.py returns without error---CPython does not encounter a syntax error. While minimizing the reproducer, I often got a case instead of an INTERNAL ERROR, Black told me I had invalid input with a syntax error, but I believed the input to be valid syntax.
Activity
[-]INENTERNAL error[/-][+]INTERNAL ERROR crash; syntax error in log[/+]