Re: [PATCH v2 09/10] clang: warn when the comma operator is used

From: Patrick Steinhardt <ps@pks.im>
Date: Mar 26, 2025, 05:54 UTC
Message-ID: <Z-OWp0NkjrMVQieH@pks.im>
In-Reply-To: <91f86c3aba9d19d5df11661675fd6c2cc049e191.1742945534.git.gitgitgadget@gmail.com>

On Tue, Mar 25, 2025 at 11:32:13PM +0000, Johannes Schindelin via GitGitGadget wrote:

Show 26 quoted lines

> From: Johannes Schindelin <johannes.schindelin@gmx.de>
> 
> When compiling Git using `clang`, the `-Wcomma` option can be used to
> warn about code using the comma operator (because it is typically
> unintentional and wants to use the semicolon instead).
> 
> Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
> ---
>  config.mak.dev | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/config.mak.dev b/config.mak.dev
> index 0fd8cc4d355..31423638169 100644
> --- a/config.mak.dev
> +++ b/config.mak.dev
> @@ -40,6 +40,10 @@ DEVELOPER_CFLAGS += -Wvla
>  DEVELOPER_CFLAGS += -Wwrite-strings
>  DEVELOPER_CFLAGS += -fno-common
>  
> +ifneq ($(filter clang9,$(COMPILER_FEATURES)),)
> +DEVELOPER_CFLAGS += -Wcomma
> +endif
> +
>  ifneq ($(filter clang4,$(COMPILER_FEATURES)),)
>  DEVELOPER_CFLAGS += -Wtautological-constant-out-of-range-compare
>  endif

Let's squash the below diff into this commit. The loop already makes sure that the compiler supports the flag, so there is no need to special case Clang.

Patrick

diff --git a/meson.build b/meson.build
index dd231b669b6..a7658d62ea0 100644
--- a/meson.build
+++ b/meson.build
@@ -717,6 +717,7 @@ libgit_dependencies = [ ]
 # Makefile.
 if get_option('warning_level') in ['2','3', 'everything'] and compiler.get_argument_syntax() == 'gcc'
   foreach cflag : [
+    '-Wcomma',
     '-Wdeclaration-after-statement',
     '-Wformat-security',
     '-Wold-style-definition',