Re: [PATCH] merge-file: fix build warning with gcc 4.8.5
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(+)
Show changes to config.mak.dev +4 −0
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
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