[libcamera-devel] [PATCH] py: Drop redundant std::move()

[Kieran Bingham]

Quoting Laurent Pinchart via libcamera-devel (2023-01-24 23:36:24)
> gcc-13 warns that the valueOrTuple() function has a redundant
> std::move() in a return statement:
> 
> ../../src/py/libcamera/py_helpers.cpp: In instantiation of ‘pybind11::object valueOrTuple(const libcamera::ControlValue&) [with T = bool]’:
> ../../src/py/libcamera/py_helpers.cpp:38:28:   required from here
> ../../src/py/libcamera/py_helpers.cpp:28:35: error: redundant move in return statement [-Werror=redundant-move]
>    28 |                 return std::move(t);

ohhh - this may be just too pedantic for me. Explicitly stating
std::move(t) when the compiler knows it is a move may be redundant to
the compiler, but it's not redundant to the reader?!

Doesn't this help make it clear that the t is being moved... in which
case it's helpful self documenting code?

I'm normally all for warnings, but this one is annoying.

https://developers.redhat.com/blog/2019/04/12/understanding-when-not-to-stdmove-in-c
states that this isn't a 'pessimizing' operation, it's just redundant,
but it does make it clearer that a move is expected to occur?

> 
> Drop it.
> 
> Signed-off-by: Laurent Pinchart <laurent.pinchart at ideasonboard.com>
> ---
>  src/py/libcamera/py_helpers.cpp | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/src/py/libcamera/py_helpers.cpp b/src/py/libcamera/py_helpers.cpp
> index 79891ab63862..5bedea047e31 100644
> --- a/src/py/libcamera/py_helpers.cpp
> +++ b/src/py/libcamera/py_helpers.cpp
> @@ -25,7 +25,7 @@ static py::object valueOrTuple(const ControlValue &cv)
>                 for (size_t i = 0; i < cv.numElements(); ++i)
>                         t[i] = v[i];
>  
> -               return std::move(t);
> +               return t;
>         }
>  
>         return py::cast(cv.get<T>());
> 
> base-commit: 13986d6ce3ab64c44a8f086ef8942f56bbedff63
> prerequisite-patch-id: f6a3b225240a9069104d326be29ae2451ba8e9f0
> prerequisite-patch-id: 8d95f21764dd480d4197b573e213721a7b6dae42
> prerequisite-patch-id: 7eff091a4898b00438bac219873379769811c391
> -- 
> Regards,
> 
> Laurent Pinchart
>