Query with TCH00[1-3] and if False

[AA-Turner]

Ruff version 0.0.238.

Sometimes in runtime code I use if False to avoid importing from typing if I would only be using TYPE_CHECKING. (All three forms pass MyPy.)

Ruff reports this as a TCH003 issue, I wonder if if False or if 0 could be added to the detection heuristic currently used for if TYPE_CHECKING?

If you'd prefer not to, no worries -- this is easy to add a # NoQA: TCH00X comment to.

(sphinx) PS I:\Development\sphinx> ruff --isolated --select TCH bug.py
bug.py:4:23: TCH003 Move standard library import `types.TracebackType` into a type-checking block
Found 1 error.
(sphinx) PS I:\Development\sphinx> type bug.py                                   
from __future__ import annotations

if False:
    from types import EllipsisType

spam: EllipsisType = ...
(sphinx) PS I:\Development\sphinx> ruff --isolated --select TCH bug.py
bug.py:4:23: TCH003 Move standard library import `types.EllipsisType` into a type-checking block
Found 1 error.
(sphinx) PS I:\Development\sphinx> ruff --version                     
ruff 0.0.238
(sphinx) PS I:\Development\sphinx> 

A

[charliermarsh]

Woah, that works?

[charliermarsh]

Let me think on it 😂

[charliermarsh]

I'm reading that if False was the convention in older Python versions (like 3.5.0).

I try not to support anything pre-3.7 but I guess in this case it costs me ~nothing to support it.

[charliermarsh]

Can you verify for me that at least one other type checker (like Pyright or Pyre) respects this?

[AA-Turner]

Pyre passes on if False and if 0 (through WSL, only if False shown here):

(venv) adam:/mnt/i/Development/Sphinx$ cat bug/bug.py
from __future__ import annotations

if False:
    from types import EllipsisType

spam: EllipsisType = ...
(venv) adam:/mnt/i/Development/Sphinx$ pyre --source-directory bug/ check
ƛ No type errors found
(venv311) adam@Gyrostats:/mnt/i/Development/Sphinx$

Pyright passes only with if 0:

PS I:\Development\sphinx> type bug.py
from __future__ import annotations

if 0:
    from types import EllipsisType

spam: EllipsisType = ...
PS I:\Development\sphinx> pyright bug.py
[...elided...]
pyright 1.1.292
0 errors, 0 warnings, 0 informations
Completed in 0.777sec

A