From: Junio C Hamano <gitster@pobox.com>
Date: Fri, 19 Jun 2026 22:27:08 GMT
Subject: Re: [PATCH v3] config.mak.uname: avoid macOS dup-library warning
Message-ID: <xmqqv7bei2tf.fsf@gitster.g>
In-Reply-To: <pull.2314.v3.git.git.1781901127385.gitgitgadget@gmail.com>

"Harald Nordgren via GitGitGadget" <gitgitgadget@gmail.com> writes:

> From: Harald Nordgren <haraldnordgren@gmail.com>
>
> Building on macOS with Xcode 15 or newer emits:
>
>     ld: warning: ignoring duplicate libraries: 'libgit.a',
>     'target/release/libgitcore.a'
>
> Some link recipes list the same archive twice, which is harmless.
> Quiet the warning instead.
>
> Pass -Wl,-no_warn_duplicate_libraries on Xcode 15 and newer, whose
> linkers added both the warning and the suppression flag (ld64-907
> and dyld-1009). Earlier linkers reject the flag, so gate on the
> linker version. Broaden the existing -fno-common version probe to
> also match the "ld64-NNN" and "dyld-NNN" forms Xcode 15 reports.
>
> Signed-off-by: Harald Nordgren <haraldnordgren@gmail.com>
> ---

Yeah, this looks like what I expected.

A few things to note.

 * Can folks with different versions of Xcode (or is 15 sufficiently
   old that practically nobody is expected to have anything older?)
   test this patch?

 * We only patch Makefile here; can folks who use meson report how
   well your build goes?

Thanks.

>  config.mak.uname | 11 +++++++++--
>  1 file changed, 9 insertions(+), 2 deletions(-)
>
> diff --git a/config.mak.uname b/config.mak.uname
> index 8719e09f66..9ebd240378 100644
> --- a/config.mak.uname
> +++ b/config.mak.uname
> @@ -173,8 +173,15 @@ ifeq ($(uname_S),Darwin)
>  		NEEDS_GOOD_LIBICONV = UnfortunatelyYes
>          endif
>  
> -	# Silence Xcode 16.3+ linker warning about __DATA,__common alignment.
> -	LD_MAJOR_VERSION = $(shell ld -v 2>&1 | sed -n 's/.*PROJECT:ld-\([0-9]*\).*/\1/p')
> +	# ld reports "PROJECT:{ld,ld64,dyld}-NNN", match any of the three.
> +	LD_MAJOR_VERSION = $(shell ld -v 2>&1 | sed -n 's/.*PROJECT:[^ ]*-\([0-9][0-9]*\).*/\1/p')
> +
> +	# Silence the Xcode 15+ warning about archives listed more than once.
> +        ifeq ($(shell test -n "$(LD_MAJOR_VERSION)" && test "$(LD_MAJOR_VERSION)" -ge 907 && echo 1),1)
> +		BASIC_LDFLAGS += -Wl,-no_warn_duplicate_libraries
> +        endif
> +
> +	# Silence the Xcode 16.3+ warning about __DATA,__common alignment.
>          ifeq ($(shell test -n "$(LD_MAJOR_VERSION)" && test "$(LD_MAJOR_VERSION)" -ge 1167 && echo 1),1)
>  		BASIC_CFLAGS += -fno-common
>          endif
>
> base-commit: 95e20213faefeb95df29277c58ac1980ab68f701