build failed if -DUSE_ICONV=ON is given

[leleliu008]

Reproduction steps

curl -LO https://github.com/libgit2/libgit2/archive/v1.5.1.tar.gz
tar vxf v1.5.1.tar.gz
cd libgit2-1.5.1

cmake \
    -S . \
    -B build.d \
    -DBUILD_TESTS=OFF \
    -DBUILD_EXAMPLES=OFF \
    -DBUILD_SHARED_LIBS=OFF \
    -DUSE_SSH=OFF \
    -DUSE_ICONV=ON \
    -DUSE_HTTPS=OpenSSL \
    -DREGEX_BACKEND=pcre2 \
    -DCMAKE_FIND_ROOT_PATH='/home/leleliu008/.ppkg/installed/openssl;/home/leleliu008/.ppkg/installed/pcre2;/home/leleliu008/.ppkg/installed/zlib;/home/leleliu008/.ppkg/installed/libiconv' \
    -DCMAKE_C_FLAGS=-I/home/leleliu008/.ppkg/installed/openssl/include \
    -DCMAKE_VERBOSE_MAKEFILE=ON \
    -DCMAKE_FIND_DEBUG_MODE=ON \
    -DCMAKE_FIND_USE_CMAKE_PATH=ON \
    -DCMAKE_FIND_USE_CMAKE_ENVIRONMENT_PATH=OFF \
    -DCMAKE_FIND_USE_SYSTEM_ENVIRONMENT_PATH=OFF \
    -DCMAKE_FIND_USE_CMAKE_SYSTEM_PATH=OFF \
    -DCMAKE_FIND_USE_INSTALL_PREFIX=OFF \
    -DCMAKE_INCLUDE_PATH=/include \
    -DCMAKE_LIBRARY_PATH=/lib \
    -DCMAKE_PROGRAM_PATH='/bin;/sbin'
cmake --build build.d

Expected behavior

ca be successfully built.

Actual behavior

/usr/bin/ld: ../util/CMakeFiles/util.dir/fs_path.c.o: in function `git_fs_path_iconv_init_precompose':
/home/leleliu008/tmp/tmp.d/tmp.d/libgit2-1.5.1/src/util/fs_path.c:982: undefined reference to `libiconv_open'
/usr/bin/ld: ../util/CMakeFiles/util.dir/fs_path.c.o: in function `git_fs_path_iconv_clear':
/home/leleliu008/tmp/tmp.d/tmp.d/libgit2-1.5.1/src/util/fs_path.c:990: undefined reference to `libiconv_close'
/usr/bin/ld: ../util/CMakeFiles/util.dir/fs_path.c.o: in function `git_fs_path_iconv':
/home/leleliu008/tmp/tmp.d/tmp.d/libgit2-1.5.1/src/util/fs_path.c:1015: undefined reference to `libiconv'
collect2: error: ld returned 1 exit status
gmake[2]: *** [src/cli/CMakeFiles/git2_cli.dir/build.make:596: git2_cli] Error 1
gmake[2]: Leaving directory '/home/leleliu008/tmp/tmp.d/tmp.d/libgit2-1.5.1/build.d'
gmake[1]: *** [CMakeFiles/Makefile2:326: src/cli/CMakeFiles/git2_cli.dir/all] Error 2
gmake[1]: Leaving directory '/home/leleliu008/tmp/tmp.d/tmp.d/libgit2-1.5.1/build.d'
gmake: *** [Makefile:139: all] Error 2

cmake-config.log cmake-build.log

Version of libgit2 (release number or SHA1)

https://github.com/libgit2/libgit2/archive/v1.5.1.tar.gz

Operating system(s) tested

ubuntu-22.10

more

I noticed that cmake config log say Found Iconv: provided by libc, this is not correct, I using a seperate libiconv, I do not use the iconv functions in libc. It seems that libiconv.so was not linked into the git2 due to it was expected to be provided by libc but actually it was in a seperate library.

[ethomson]

Thanks for the bug report. We can take a look.

In the meantime, I'm curious why you want iconv on Linux at all?

[leleliu008]

libiconv implemented by GNU is full featured, although musl libc also implements libiconv, but older version do not support all features in GNU's libiconv.

[ethomson]

That's not what I'm asking - iconv support is really only useful for core.precomposeUnicode which is a macOS feature. I'm curious why you're enabling it on Linux?

[leleliu008]

I'm writing a package manager, I find this library supports libiconv, I enable it for all platfroms.

[leleliu008]

If don't expect to be used in GNU/Linux system, it's better to give a warnning if user enables it, I didn't dig into the source code, although your docs say iconv (OSX) to handle the HFS+ path encoding peculiarities, I thought your build system would ignore -DUSE_ICONV=ON on GNU/Linux, but actually it didn't, so I thought it was a bug. If it isn't a bug, fell free to close it.

[ethomson]

It should work with USE_ICONV on Unix, and we should fix it if it doesn't. I was just curious about your use case.