Re: [PATCH] erofs-utils: build: link tools with liberofs dependencies

[Gao Xiang <xiang@kernel.org>]

Hi Yifan,

On Fri, May 29, 2026 at 03:17:02PM +0800, Yifan Zhao wrote:
> liberofs.la is a noinst libtool archive, so relying on its
> dependency_libs to carry external libraries is not enough for
> static-only dependencies.
> 
> For example, when liblzma is installed as a static libtool archive,
> libtool consumes -llzma while creating liberofs.la but does not record it
> in dependency_libs.  The final tools then link only with liberofs.la and
> fail with undefined lzma_* references.
> 
> Collect liberofs external libraries in LIBEROFS_LIBS and use it for both
> liberofs.la and the final tools, so final executable links see the
> pkg-config supplied liblzma flags directly.
> 
> Reported-by: Guo Xuenan <guoxuenan@huawei.com>
> Fixes: 6c2a000782b2 ("erofs-utils: lib: add test for s3erofs_prepare_url()")
> Assisted-by: Codex:GPT-5.5
> Signed-off-by: Yifan Zhao <zhaoyifan28@huawei.com>
> ---
> To reproduce link error:
> 
>     ./autogen.sh
>     PKG_CONFIG_PATH=/path/to/xz-static/lib/pkgconfig ./configure
>     make -j
> 
> Then {mkfs,dump,fsck}.erofs reports missing lzma_* symbol as `-llzma`
> missing in ld flags.
> 
>  configure.ac      | 17 +++++++++++++++++
>  dump/Makefile.am  |  2 +-
>  fsck/Makefile.am  |  4 ++--
>  fuse/Makefile.am  |  5 +++--
>  lib/Makefile.am   | 14 +++-----------
>  mkfs/Makefile.am  |  2 +-
>  mount/Makefile.am |  2 +-
>  7 files changed, 28 insertions(+), 18 deletions(-)
> 
> diff --git a/configure.ac b/configure.ac
> index f68bb74..17b4856 100644
> --- a/configure.ac
> +++ b/configure.ac
> @@ -790,6 +790,23 @@ AM_CONDITIONAL([ENABLE_STATIC_FUSE], [test "x${enable_static_fuse}" = "xyes"])
>  AM_CONDITIONAL([ENABLE_OCI], [test "x${have_oci}" = "xyes"])
>  AM_CONDITIONAL([ENABLE_FANOTIFY], [test "x${have_fanotify}" = "xyes"])
>  
> +LIBEROFS_LIBS="${libselinux_LIBS} ${libuuid_LIBS} ${liblz4_LIBS} \
> +${liblzma_LIBS} ${zlib_LIBS} ${libdeflate_LIBS} ${libzstd_LIBS} \
> +${libqpl_LIBS} ${libcurl_LIBS} ${openssl_LIBS} ${json_c_LIBS}"
> +AS_IF([test "x${have_xxhash}" = "xyes"], [
> +  LIBEROFS_LIBS="${LIBEROFS_LIBS} ${libxxhash_LIBS}"
> +])
> +AS_IF([test "x${have_s3}" = "xyes"], [
> +  LIBEROFS_LIBS="${LIBEROFS_LIBS} ${libxml2_LIBS}"
> +])
> +AS_IF([test "x${enable_multithreading}" != "xno"], [
> +  LIBEROFS_LIBS="${LIBEROFS_LIBS} -lpthread"
> +])
> +AS_IF([test "x${build_linux}" = "xyes"], [
> +  LIBEROFS_LIBS="${LIBEROFS_LIBS} ${libnl3_LIBS}"
> +])

Although I admit that I'm not super happy with this approach, but it
seems that we have to do like this.

My only question here is that why  ${libxxhash_LIBS},  ${libxml2_LIBS}
and ${libnl3_LIBS} cannot be appended directly to LIBEROFS_LIBS as
others.

But I think it's fine to guard `-lpthread` with enable_multithreading
tho.

Thanks,
Gao Xiang