[libxml2] (OSX) Dependent ports fail due to missing iconv linkage

[Neumann-A]

Host Environment

• OS: OSX
• Compiler: revision

Failure logs

Undefined symbols for architecture x86_64:
  "___darwin_check_fd_set_overflow", referenced from:
      _xmlNanoFTPCheckResponse in libxml2.a(nanoftp.c.o)
      _xmlNanoFTPCloseConnection in libxml2.a(nanoftp.c.o)
      _xmlNanoFTPList in libxml2.a(nanoftp.c.o)
      _xmlNanoFTPGet in libxml2.a(nanoftp.c.o)
  "_iconv", referenced from:
      _xmlIconvWrapper in libxml2.a(encoding.c.o)
  "_iconv_close", referenced from:
      _xmlFindCharEncodingHandler in libxml2.a(encoding.c.o)
      _xmlCharEncCloseFunc in libxml2.a(encoding.c.o)
  "_iconv_open", referenced from:
      _xmlFindCharEncodingHandler in libxml2.a(encoding.c.o)
ld: symbol(s) not found for architecture x86_64

Additional context
the vcpkg-cmake-wrapper.cmake in libxml2 must be changed to also add the required dependencies on OSX. Observed in build failure of on OSX CI in #10770

Missing symbol ___darwin_check_fd_set_overflow might be an infrastructure/XCode bug or requires a rebuild of libxml?

[NancyLi1013]

Hi @Neumann-A
Thanks for posting this issue.
Could you please help confirm on which version of your compiler you encountered this?
It seems a bug introduced by Xcode 11.4.

[Neumann-A]

Could you please help confirm on which version of your compiler you encountered this?

This was on vcpkg CI so you should know which compiler you use/used there to build libxml2. Maybe just need to rebuild libxml2 once for CI (assuming you updated Xcode on CI to a version without the bug).

[NancyLi1013]

Thanks for your info.
But I didn't see this failure for libxml2 in the PR #10770.

libxml2:x64-osx: pass: 829f2a0dc6353fb46c06b4c3028eaf4bb6b9fb84

It seems to be passed.
Where did you see this?
If this is really on vcpkg CI, we will try to solve this.

[Neumann-A]

@NancyLi1013: It is in the log of the cmake port build failure.
install-x64-osx-dbg-out.log @ Line 404 & 422

[NancyLi1013]

Thanks. I have noticed this and will look into it.

[NancyLi1013]

It seems that there is no the following error in current log.

     ___darwin_check_fd_set_overflow", referenced from:
    _xmlNanoFTPCheckResponse in libxml2.a(nanoftp.c.o)
    _xmlNanoFTPCloseConnection in libxml2.a(nanoftp.c.o)
    _xmlNanoFTPList in libxml2.a(nanoftp.c.o)
    _xmlNanoFTPGet in libxml2.a(nanoftp.c.o)

But the issue caused by iconv still exists.

Undefined symbols for architecture x86_64:
  "_iconv", referenced from:
      _xmlIconvWrapper in libxml2.a(encoding.c.o)
  "_iconv_close", referenced from:
      _xmlFindCharEncodingHandler in libxml2.a(encoding.c.o)
      _xmlCharEncCloseFunc in libxml2.a(encoding.c.o)
  "_iconv_open", referenced from:
      _xmlFindCharEncodingHandler in libxml2.a(encoding.c.o)
ld: symbol(s) not found for architecture x86_64
clang: error: linker command failed with exit code 1 (use -v to see invocation)

I checked the CMakeLists.txt and iconv has been linked.

I plan to submitted a PR to test this and confirm if there is something wrong with libxml2 on osx pipeline.

[NancyLi1013]

@strega-nil
Could you please help take a look about this issue?

It should not a usage bug for libxml2. I try to create a project to build on osx without any error.
In addition, I also noticed that iconv is only added on Windows platform in vcpkg-cmake-wrapper.cmake. But this issue only occured on osx instead of osx and linux.

So I'm not sure what happened on osx.

[Neumann-A]

turns out:

libiconv portfile:

if(NOT VCPKG_TARGET_IS_WINDOWS)
    set(VCPKG_POLICY_EMPTY_PACKAGE enabled)
    file(MAKE_DIRECTORY ${CURRENT_PACKAGES_DIR}/share/unofficial-iconv)
    file(COPY ${CMAKE_CURRENT_LIST_DIR}/unofficial-iconv-config.cmake DESTINATION ${CURRENT_PACKAGES_DIR}/share/unofficial-iconv)
    return()
endif()

So libxml2 is probably not linking iconv from within vcpkg but a system version. The linux machine does not link iconv into libxml2 seems to have a shared library of iconv installed while while on osx it gets linked? The reasons for that are the unofficial::iconv targets.
libiconv should probably be fixed to build iconv and charset on all platforms.