On Fri, Jan 14 2022, Junio C Hamano wrote:
> Junio C Hamano <gitster@xxxxxxxxx> writes:
>
>>> I think we had this discussion about FreeBSD before and that's why I
>>> specifically dropped that option from the main makefile. We can either
>>> drop that patch, or we can set it to -std=gnu11 and tell folks setting
>>> DEVELOPER to use a system released in the last five years. I think we
>>> can be a little stricter with what we require in the case of DEVELOPER
>>> than we might be otherwise.
>>
>> But that is not being stricter, but looser, no? I thought that the
>> point of -std=gnu99 was to allow us to use C99 features while catching
>> use of language features newer than that, and use of -std=gnu11 will
>> defeat half the point, wouldn't it?
>
> If FreeBSD (or any other platform) cannot do "reject features beyond
> C99", I am perfectly OK to drop -std=gnu99 on such a place.
>
> DEVELOPER=YesPlease ought to be a collection of settings that helps
> the developers the most. So on platforms that *can* do "reject
> features beyond C99", I prefer to have it enabled when
> DEVELOPER=YesPlease is given.
>
> It seems that -std=gnu99 is only added conditionally even in today's
> config.mak.dev, so it is fine if we dropped -std=gnu99 from there.
> Which means that developers on FreeBSD cannot participate in vetting
> use of features beyond C99, but there are developers on other
> platforms who will, so it's not too bad, I would say.
>
> As config.mak.dev is included after config.mak.uname, something like
> this may be sufficient, perhaps?
Wasn't the initial goal here to check whether we'd accidentally include
C99? Just checking on GCC/Clang somewhere seems sufficient enough,
I.e. something like:
diff --git a/ci/lib.sh b/ci/lib.sh
index 9d28ab50fb4..94d0d4127b9 100755
--- a/ci/lib.sh
+++ b/ci/lib.sh
@@ -209,6 +209,9 @@ linux-leaks)
export SANITIZE=leak
export GIT_TEST_PASSING_SANITIZE_LEAK=true
;;
+linux-gcc|linux-clang)
+ MAKEFLAGS="$MAKEFLAGS CFLAGS=-std=gnu99"
+ ;;
esac
MAKEFLAGS="$MAKEFLAGS CC=${CC:-cc}"
diff --git a/config.mak.dev b/config.mak.dev
index d4afac6b51f..216f92493fc 100644
--- a/config.mak.dev
+++ b/config.mak.dev
@@ -20,10 +20,6 @@ endif
endif
endif
-ifneq ($(or $(filter gcc6,$(COMPILER_FEATURES)),$(filter clang7,$(COMPILER_FEATURES))),)
-DEVELOPER_CFLAGS += -std=gnu99
-endif
-
DEVELOPER_CFLAGS += -Wdeclaration-after-statement
DEVELOPER_CFLAGS += -Wformat-security
DEVELOPER_CFLAGS += -Wold-style-definition
We're just starting to get into the whack-a-mole of hardcoding OS's and
compiler versions, it's not all versions of FreeBSD, probably not just
that OS etc.
I've also wondered why we can't just ship our own super-light version of
autoconf to run some real probes, and as a result eventually get rid of
configure.ac, ./detect-compiler, the version hardcoding in
config.mak.dev etc.
Just something as simple as extending this:
diff --git a/Makefile b/Makefile
index 5580859afdb..f197a07c100 100644
--- a/Makefile
+++ b/Makefile
@@ -2557,6 +2557,15 @@ else
$(OBJECTS): $(LIB_H) $(GENERATED_H)
endif
+ifdef DEVELOPER
+probe/std.mak:
+ @mkdir -p $(@D)
+ $(QUIET_GEN)if $(CC) -E -std=gnu99 - </dev/null >/dev/null; then \
+ echo 'DEVELOPER_CFLAGS += -std=gnu99'; \
+ fi >$@
+include probe/std.mak
+endif
+
ifeq ($(GENERATE_COMPILATION_DATABASE),yes)
all:: compile_commands.json
compile_commands.json:
