[libcamera-devel] [PATCH 10/10] meson: Enable shadowed variable warning

[Laurent Pinchart]

Hi Kieran,

Thank you for the patch.

On Tue, Oct 13, 2020 at 04:12:41PM +0100, Kieran Bingham wrote:
> Shadowing variables can lead to unexpected bugs where a code path
> utilises a variable that may not have been intended by the developer,
> leading to hard to find bugs.
> 
> Enable warnings for shadowed variables as defined at:
>   https://gcc.gnu.org/onlinedocs/gcc/Warning-Options.html#index-Wshadow
> 
> As an effect of utilising -Werror, this will cause variable or type
> shadowing to become a build-time error.
> 
> Suggested-by: Laurent Pinchart <laurent.pinchart at ideasonboard.com>
> Signed-off-by: Kieran Bingham <kieran.bingham at ideasonboard.com>
> 
> ---
> 
> The reference here is that I lost around 2 hours digging into a bug that
> looked like some other code path was calling a destructor or such, but
> was because I had accidentally aliased a private member variable in the
> constructor, so all my initialisation was lost after the constructor
> completed.

It's sometimes nice to be able to shadow variables, but I think the
debugging pain is too high of a cost for that.

Reviewed-by: Laurent Pinchart <laurent.pinchart at ideasonboard.com>

>  meson.build | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/meson.build b/meson.build
> index de15cc16da81..10423f523ca5 100644
> --- a/meson.build
> +++ b/meson.build
> @@ -38,6 +38,7 @@ if cc.has_header_symbol('stdlib.h', 'secure_getenv', prefix : '#define _GNU_SOUR
>  endif
>  
>  common_arguments = [
> +    '-Wshadow',
>      '-include', 'config.h',
>  ]

-- 
Regards,

Laurent Pinchart