On 01/03, Junio C Hamano wrote:
> Jonathan Nieder <jrnieder@xxxxxxxxx> writes:
>
> > In October, Thomas Gummerer wrote:
> >> On 10/12, Jonathan Nieder wrote:
> >>> Jeff King wrote:
> >>> ...
> >>>> -Wformat is part of -Wall, which we already turn on by default (even for
> >>>> non-developer builds).
> > ...
> > As discussed in [1], autoconf appears to not put -Wall in CFLAGS:
> >
> > $ make configure
> > GEN configure
> > $ ./configure
> > [...]
> > config.status: creating config.mak.autogen
> > config.status: executing config.mak.autogen commands
> > $ grep CFLAGS config.mak.autogen
> > CFLAGS = -g -O2
> > PTHREAD_CFLAGS=-pthread
> >
> > So this trap for the unwary is still around.
> >
> > Can we revive this patch? Does it just need a clearer commit message,
> > or were there other objections?
>
> I think it is a good idea to give fallback/redundancy for this
> case. I do not have strong opinion between -Wall and -Wformat,
> but I'd probably vote for the former if pressed.
Just catching up after some time off over Christmas, thanks for tying
this up!
I agree with the choice of adding -Wall to the CFLAGS here, so even if
it is not added to the CFLAGS generated by autoconf (or in mnually set
up CFLAGS such as in my original case), we still get a complete set of
warnings when DEVELOPER=YesPlease is set.
> -- >8 --
> From: Thomas Gummerer <t.gummerer@xxxxxxxxx>
> Date: Fri, 12 Oct 2018 19:40:37 +0100
> Subject: [PATCH] config.mak.dev: add -Wformat
>
> 801fa63a90 ("config.mak.dev: add -Wformat-security", 2018-09-08)
> added the "-Wformat-security" to the flags set in config.mak.dev.
> In the gcc man page this is documented as:
>
> If -Wformat is specified, also warn about uses of format
> functions that represent possible security problems. [...]
>
> The commit did however not add the "-Wformat" flag, but instead
> relied on the fact that "-Wall" is set in the Makefile by default
> and that "-Wformat" is part of "-Wall".
>
> Unfortunately, those who use config.mak.autogen generated with the
> autoconf to configure toolchain do *not* get "-Wall" in their CFLAGS
> and the added -Wformat-security had no effect. Worse yet, newer
> versions of gcc (gcc 8.2.1 in this particular case) warn about the
> lack of "-Wformat" and thus compilation fails only with this option
> set.
>
> We could fix it by adding "-Wformat", but in general we do want all
> checks included in "-Wall", so let's add it to config.mak.dev to
> cover more cases.
>
> Signed-off-by: Thomas Gummerer <t.gummerer@xxxxxxxxx>
> Helped-by: Jeff King <peff@xxxxxxxx>
> Helped-by: Jonathan Nieder <jrnieder@xxxxxxxxx>
> [jc: s/-Wformat/-Wall/]
> Signed-off-by: Junio C Hamano <gitster@xxxxxxxxx>
> ---
> config.mak.dev | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/config.mak.dev b/config.mak.dev
> index bfbd3df4e8..74337f1f92 100644
> --- a/config.mak.dev
> +++ b/config.mak.dev
> @@ -1,6 +1,7 @@
> ifeq ($(filter no-error,$(DEVOPTS)),)
> CFLAGS += -Werror
> endif
> +CFLAGS += -Wall
> CFLAGS += -Wdeclaration-after-statement
> CFLAGS += -Wformat-security
> CFLAGS += -Wno-format-zero-length
> --
> 2.20.1-2-gb21ebb671b
>
