Re: [PATCH v2] add DEVELOPER makefile knob to check for acknowledged warnings

From: Jeff King <peff@peff.net>
Date: May 10, 2017, 04:59 UTC
Message-ID: <20170510045914.adtb5qmnc53z4vdq@sigill.intra.peff.net>
In-Reply-To: <CACBZZX4=QePHqDFnxvTSJ4siNv6TVzUvhCpA91aY8APZTpGEfQ@mail.gmail.com>

On Tue, May 02, 2017 at 03:22:23PM +0200, Ævar Arnfjörð Bjarmason wrote:

Show 13 quoted lines

> Is there any way with this to both supply CFLAGS & DEVELOPER=1 on the
> command-line, to get my custom -O<whatever> & these -W flags? I.e.:
> 
> $ make DEVELOPER=1 V=1
> [...] -g -O2 -Wall -Werror -Wdeclaration-after-statement
> -Wno-format-zero-length -Wold-style-definition -Woverflow
> -Wpointer-arith -Wstrict-prototypes -Wunused -Wvla -I. [...]
> $ make DEVELOPER=1 CFLAGS="-g -O0 -Wall" V=1
> [...] -g -O0 -Wall -I. [...]
> 
> I thought the second case would prepend my "-g -O0 -Wall" but then be
> followed by the various -W developer flags, but it isn't, am I just
> doing something stupid, or is there no way to combine these two?

The problem is that when you give "make" a variable on the command line, it overrides all of the modifications. So if you were to set that CFLAGS in your config.mak, I think everything would work as you expect.

I actually do this in my config.mak:

  O = 0
  CFLAGS += -g -O$(O)

which lets me override the optimization level as a one-off on the command-line:

  make O=2

without disturbing the rest of the CFLAGS. I also do this:

  CFLAGS += $(EXTRA_CFLAGS)

as a catch-all, so that I can do:

  make EXTRA_CFLAGS=-Wone-off-warning-that-I-am-testing

Perhaps those are things the main Makefile should support. I dunno. You could see the full depths of my depravity at:

  https://github.com/peff/git/blame/meta/config/config.mak

(I linked to the blame view because there are a lot of WTF bits in there that are explained by the commit messages).

-Peff