Re: [PATCH] build: fix meson warning about using compiler warning flags

[Luca Boccassi <bluca@debian.org>]

On Fri, 2022-01-21 at 15:53 +0000, Bruce Richardson wrote:
> Each build, meson would issue a warning reporting that the
> "warning_level" setting should be used in place of adding -Wextra
> directly to our build commands. Testing with meson 0.61 shows that the
> only difference for gcc and clang builds between warning levels 1 and
> 2 is the addition of -Wextra, so we can remove the warning by deleting
> our explicit set of Wextra and changing the build defaults to
> warning_level 2.
> 
> Fixes: 524a0d5d66b9 ("build: enable extra warnings with meson")
> 
> Signed-off-by: Bruce Richardson <bruce.richardson@intel.com>
> ---
> 
> NOTE1: Not putting CC stable for this patch, I don't believe it's worth
> the risk of backporting.
> 
> NOTE2: For reference, when building a test "hello world" project with
> different warning levels, the following flags are used by meson:
> 
> warning_level=0: <none>
> warning_level=1: -Wall -Winvalid-pch
> warning_level=2: -Wall -Winvalid-pch -Wextra
> warning_level=3: -Wall -Winvalid-pch -Wextra -Wpedantic
> ---
>  config/meson.build | 5 ++---
>  meson.build        | 2 +-
>  2 files changed, 3 insertions(+), 4 deletions(-)
> 
> diff --git a/config/meson.build b/config/meson.build
> index ee12318d4f..7134e80e8d 100644
> --- a/config/meson.build
> +++ b/config/meson.build
> @@ -247,10 +247,9 @@ endif
>  add_project_arguments('-include', 'rte_config.h', language: 'c')
>  
> 
>  # enable extra warnings and disable any unwanted warnings
> +# -Wall is added by default at warning level 1, and -Wextra
> +# at warning level 2 (DPDK default)
>  warning_flags = [
> -        # -Wall is added by meson by default, so add -Wextra only
> -        '-Wextra',
> -
>          # additional warnings in alphabetical order
>          '-Wcast-qual',
>          '-Wdeprecated',
> diff --git a/meson.build b/meson.build
> index 1223b79d74..070243a33d 100644
> --- a/meson.build
> +++ b/meson.build
> @@ -7,7 +7,7 @@ project('DPDK', 'C',
>          version: run_command(find_program('cat', 'more'),
>              files('VERSION'), check: true).stdout().strip(),
>          license: 'BSD',
> -        default_options: ['buildtype=release', 'default_library=static'],
> +        default_options: ['buildtype=release', 'default_library=static', 'warning_level=2'],
>          meson_version: '>= 0.49.2'
>  )
>  
> 

Acked-by: Luca Boccassi <bluca@debian.org>

-- 
Kind regards,
Luca Boccassi