Re: [PATCH] perf pmu-events: Fix jevents.py type annotations for mypy 2.x

[sashiko-bot@kernel.org]

> Since the build runs mypy whenever it is installed, the perf build fails
> with mypy 2.4 on 7 errors in jevents.py, e.g.:
> 
>   pmu-events/jevents.py:542: error: Item "None" of "str | None" has no
>   attribute "replace"  [union-attr]
>   pmu-events/jevents.py:563: error: Item "None" of "BigCString | None"
>   has no attribute "offsets"  [union-attr]
> 
> Both come from wrong annotations rather than from code that can see
> None:
>  - unit_to_pmu() is annotated as returning Optional[str] but always
>    returns a string, so JsonEvent.pmu is typed as optional where it is
>    used as a str.
>  - _bcs is set to None before the BigCString class is defined and only
>    assigned an instance after it, so mypy types it as BigCString | None.
> 
> Correct the return type and declare _bcs with its type instead of the
> None placeholder. The generated pmu-events.c and pmu-events-string.c
> are unchanged, and mypy 1.9 still passes.
> 
> Fixes: b3e9c396d0ac ("perf build: Make mypy build test opt-out (NO_MYPY=1)")
> Assisted-by: LLM
> Signed-off-by: Lalit Maganti <lalitmaganti@gmail.com>

Sashiko has reviewed this patch and found no issues.

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Sashiko AI review · https://sashiko.dev/#/patchset/20261018065345.918176-1-lalitmaganti@gmail.com?part=1