Multiline inconsistent indented (inconsistent scope) # fmt: on / # fmt: off fails: Black produced code that is not equivalent to the source on pass 1

[SamuelMarks]

Describe the bug

I am writing my own Concrete Syntax Tree parser/emitter in Python, but I am using black as my code formatter so I want black to ignore the 'fancy' Python syntax I am trying to support with my parser. So I've got a bunch of badly formatted Python code that I want to support with my parser.

To Reproduce

def add1(foo):
    def adder(a: int, b: int) -> int:
        # fmt: off
        res: \
            int \
            = a + b
        return res

    r = (
        add(foo, 1)
        or
        adder(foo, 1)
    )
    # fmt: on

Expected behavior

It should work

Actual behavior

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: /tmp/blk_6ciutkwa.log

Environment

https://black.vercel.app/?version=main&state=_Td6WFoAAATm1rRGAgAhARYAAAB0L-Wj4AE_AKFdAD2IimZxl1N_WlbvK5V8IsyYXSZYzCxvB11Od7QFS_cUQRnVWTnEOnFGqeIVOh-6xpWYQw80rntIdUcNTZAqIYyewDaXyz571F0uxel5QXJBPZz4vzo0EFPhMsonxVlUzlqOg0_Xb1km-YJFCPRioooVe1ft1ydHHh6KUs4CK4ZdWV7pO9zBDSqDJun-2hPLYtedLWs2Bub_aZDRwt75JGqiAAAAAMTZEyWxsHatAAG9AcACAACux6gtscRn-wIAAAAABFla

[ichard26]

This isn't supported as of right now:

It doesn’t reformat blocks that start with # fmt: off and end with # fmt: on, or lines that ends with # fmt: skip. # fmt: on/off have to be on the same level of indentation. It also recognizes YAPF’s block comments to the same effect, as a courtesy for straddling code.

I'm open to supporting differently indented fmt: off/on but I make no promises on how feasible it may be. ALTHOUGH Black should really be treating the # fmt: off as unterminated and not generate invalid code.

[JelleZijlstra]

I think this is a duplicate of #569.

For your use case, I'd suggest just not running Black on your test cases.