Re: [PATCH v2 2/2] ci: compile "linux-gcc-default" job with -Og

> I was a little torn whether we really want to name the variable `O`
> here because it feels so easy to set it by accident. We could rename
> this to `OPTIMIZATION` or `OPTIMIZATION_LEVEL`, but that's quite a
> mouthful.
>
> Alternatively, if we don't want to have this variable in the first
> place, then I'm also happy to adapt the script itself to pass the
> optimization level via an argument.

>  Makefile                  | 3 ++-
>  ci/run-build-and-tests.sh | 9 +++++++++
>  2 files changed, 11 insertions(+), 1 deletion(-)
>
> diff --git a/Makefile b/Makefile
> index 59d98ba688..ff57c94fdf 100644
> --- a/Makefile
> +++ b/Makefile
> @@ -1357,7 +1357,8 @@ endif
>  # tweaked by config.* below as well as the command-line, both of
>  # which'll override these defaults.
>  # Older versions of GCC may require adding "-std=gnu99" at the end.
> -CFLAGS = -g -O2 -Wall
> +O ?= 2
> +CFLAGS = -g -O$(O) -Wall
>  LDFLAGS =
>  CC_LD_DYNPATH = -Wl,-rpath,
>  BASIC_CFLAGS = -I.
> diff --git a/ci/run-build-and-tests.sh b/ci/run-build-and-tests.sh
> index 98dda42045..0f00dbd289 100755
> --- a/ci/run-build-and-tests.sh
> +++ b/ci/run-build-and-tests.sh
> @@ -13,6 +13,15 @@ esac
>  run_tests=t
>  
>  case "$jobname" in
> +linux-gcc-default)
> +	# Warnings generated by compilers are unfortunately specific to the
> +	# optimization level. With `-O0`, many warnings won't be shown at all,
> +	# whereas the optimizations performed by our default optimization level
> +	# `-O2` will mask others. We thus use `-Og` here just so that we have
> +	# at least one job with a different optimization level so that we can
> +	# overall surface more warnings.
> +	export O=g
> +	;;
>  linux-gcc)
>  	export GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME=main
>  	;;