fmt on/off raises internal error when fmt: off in multi-level intended code block

[izikeros]

Description

Black raises error when formatting code that includes specific combination of fmt: off and fmt: on commands. The bug occurs when fmt: off is before intended block and fmt: on inside intended block. Bug occurs only in multi-level indentation (see: examples below)

To Reproduce
Try to format file with the code:

for i in range(2):
    # fmt: off
    for j in range(2):
        # fmt: on
        pass

Note: similar code but with single-level of indent not raises any error:

# fmt: off
for j in range(2):
    # fmt: on
    pass

And run it with these arguments:

$ black file.py

The resulting error is:

error: cannot format file.py: INTERNAL ERROR: Black produced code that is not equivalent to the source on pass 1. Please report a bug on https://github.com/psf/black/issues. This diff might be helpful: /var/folders/97/sr1jt8qx6b90q4hqfsv06qbc0000gq/T/blk_0vp6bvi8.log

Expected behavior

Black should format file without raising error.

Environment

• Black's version: 22.1.0
• OS and Python version: macOS 12.2 (21D49), Python 3.9.10

[felix-hilden]

Hi! As documented, # fmt: off / on have to be on the same level of indentation. We have discussed fixing this in #2140 (#569 also related), so I'll close this as a duplicate.

[felix-hilden]

Verified that this doesn't happen on the compiled version either. @izikeros If this is indeed the case, please submit another issue detailing the problem!