Re: [PATCH] merge-file: fix build warning with gcc 4.8.5
- From
Jeff King <peff@peff.net>
- Date
- Jul 29, 2022, 19:53 UTC
- Message-ID
- <YuQ60ZUPBHAVETD7@coredump.intra.peff.net>
- In-Reply-To
- <xmqqbkt7api9.fsf@gitster.g>
On Fri, Jul 29, 2022 at 08:48:46AM -0700, Junio C Hamano wrote:
Show 8 quoted lines
> I think the concensus was that we should squelch the false warning > on older compilers with -Wno-missing-braces, but then the discussion > has stalled by a suggestion to introduce a way to detect older > compilers that is different from how we do so at the same time, and > went nowhere. > > Hopefully we can add a simple -Wno-* without waiting for whole > config.mak thing getting revamped this time?
Perhaps this?
-- >8 -- 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> --- Tested on a debian jessie chroot using gcc-4.8 and 4.9. Though note that you also need to manually specify -std=gnu99 to get it to work at all with those compilers these days! So I kind of wonder if it's even worth catering to their warnings automatically.
config.mak.dev | 4 ++++ 1 file changed, 4 insertions(+)
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
-- 2.37.1.804.g1775fa20e0