Re: [PATCH] merge-file: fix build warning with gcc 4.8.5

From: Eric Sunshine <sunshine@sunshineco.com>
Date: Jul 29, 2022, 20:48 UTC
Message-ID: <CAPig+cSiAEgopj1zwR4kUG=ZLJQrNAVj0P5g4veWYD-ERr=irw@mail.gmail.com>
In-Reply-To: <YuQ60ZUPBHAVETD7@coredump.intra.peff.net>

On Fri, Jul 29, 2022 at 3:53 PM Jeff King <peff@peff.net> wrote:

Show 21 quoted lines

> Subject: [PATCH] config.mak.dev: squelch -Wno-missing-braces for older gcc
>
> Versions of gcc prior to 4.9 complain about an initialization like:
>
>   struct inner { int x; };
>   struct outer { struct inner; };
>   struct outer foo = { 0 };
>
> and insist on:
>
>   struct outer foo = { { 0 } };
>
> Newer compilers handle this just fine. And ignoring the window even on
> older compilers is fine; the resulting code is correct, but we just get
> caught by -Werror.
>
> Let's relax this for older compilers to make developer lives easier (we
> don't care much about non-developers on old compilers; they may see a
> warning, but it won't stop compilation).
>
> Signed-off-by: Jeff King <peff@peff.net>

Leaving aside for the moment the problem with Apple's oddball invented version numbers for `clang`, should this patch also take older `clang` versions into consideration rather than focusing only on `gcc`? (Of course, `clang` could be dealt with in a separate patch if you'd rather not worry about it here.)

Show 17 quoted lines

> diff --git a/config.mak.dev b/config.mak.dev
> index 335efd4620..b9878a4994 100644
> --- a/config.mak.dev
> +++ b/config.mak.dev
> @@ -59,9 +59,13 @@ endif
>
>  # uninitialized warnings on gcc 4.9.2 in xdiff/xdiffi.c and config.c
>  # not worth fixing since newer compilers correctly stop complaining
> +#
> +# Likwise, gcc older than 4.9 complains about initializing a
> +# struct-within-a-struct using just "{ 0 }"
>  ifneq ($(filter gcc4,$(COMPILER_FEATURES)),)
>  ifeq ($(filter gcc5,$(COMPILER_FEATURES)),)
>  DEVELOPER_CFLAGS += -Wno-uninitialized
> +DEVELOPER_CFLAGS += -Wno-missing-braces
>  endif
>  endif