Generated pkg-config file contain linker flags for uninstalled static libraries

[ebassi]

If a library target A depend on an uninstalled static library target B, pkgconfig.generate() will add -lB to the Libs.private key of the pkg-config file.

Meson version: 0.47.1

Example, taken from Geoclue:

• public-api/meson.build:

libgeoclue_public_api_lib = static_library('geoclue-public-api',
  libgeoclue_public_api_gen_sources,
  dependencies: base_deps,
)

libgeoclue_public_api = declare_dependency(link_with: libgeoclue_public_api_lib,
  sources: gclue_enum_types_h,
  include_directories: include_directories('.'),
  dependencies: base_deps,
)

• libgeoclue/meson.build:

libgeoclue_lib = library('geoclue-2',
  libgeoclue_sources,
  include_directories: config_inc,
  dependencies: base_deps + [
    libgeoclue_public_api,
  ],
  soversion: '0',
  version: '0.0.0',
  install: true,
)

pkgconf = import('pkgconfig')
pkgconf.generate(libgeoclue_lib,
  name: 'Geoclue Client Library',
  description: 'A convenience library to interact with Geoclue service',
  version: gclue_version,
  filebase: 'libgeoclue-' + gclue_api_version,
  subdirs: [ header_dir ],
)

• generated libgeoclue-2.0.pc file:

prefix=/home/ebassi/gnome/install
libdir=${prefix}/lib
includedir=${prefix}/include

Name: Geoclue Client Library
Description: A convenience library to interact with Geoclue service
Version: 2.4.10
Requires.private: glib-2.0 >=  2.34.0, gio-2.0 >=  2.34.0, gio-unix-2.0 >=  2.34.0
Libs: -L${libdir} -lgeoclue-2
Libs.private: -L${libdir} -lgeoclue-public-api
Cflags: /home/ebassi/gnome/install/include/libgeoclue-2.0

The -lgeoclue-public-api is wrong, and will cause any user of libgeoclue-2.0 to break.

[xclaesse]

Don't you need libgeoclue-public-api.a when doing a static link witth libgeoclue-2.a? In geoclue master I see it uses link_whole and -lgeoclue-public-api is not in the generated pc file. I think that's correct, isn't it?

[xclaesse]

The -lgeoclue-public-api is wrong, and will cause any user of libgeoclue-2.0 to break.

Only when using it for static link. When using the shared library Libs.private is not used, AFAIK.

[ebassi]

It shouldn't really matter: libgeoclue-public-api.a is not installed, so it should be folded into the installed libgeoclue-2.0.so shared library.

There are a lot of projects that use internal static libraries to build an installed shared library; the internal dependency object should be enough — you shouldn't need to use link_whole.

The reason why link_whole is not enough, incidentally, is that libgeoclue-public-api depends on generated files; using an internal dependency object allows us to correctly express the dependencies transitively.

[xclaesse]

If you're not going to provide static libraries, then use shared_library() instead of library(). As far as I know the generated pc file is correct for static links, and you must install libgeoclue-public-api.a.

[xclaesse]

Note that meson's pc generator special case shared_library() to not pull its dependencies, exactly for the case you're describing. But since geoclue uses library() it means it wants to provide the static library.

[ebassi]

That's a bit of a trap, though…

[xclaesse]

Note that at least on Ubuntu the libgeoclue-dev package does provide libgeoclue.a, so I think using link_whole and library() as in geoclue master is the right thing to do.

[ebassi]

Using link_whole breaks the build in two ways:

• the generated enumeration files are not built before libgeoclue is compiled
• if I add a link_whole and a dependency on the sources, I still get a broken build because the exported symbols are not found

[ebassi]

Reference to actual working code: https://gitlab.freedesktop.org/geoclue/geoclue/merge_requests/8

[nirbheek]

I think this related to #3937. link_with: on non-installed static libraries should work as expected, and should not require a link_whole: because that bloats the shared library.

[fanc999]

Hi,

Is this the same issue that I am hit by here? When I try to build GLib for instance with Visual Studio+Ninja, my glib-2.0.pc contains the following for Libs.private:

Libs.private: -L${libdir} -lcharset -lgnulib -lpcre -lws2_32 -lwinmm

Note the part where it says -lcharset and -lgnulib, which are static .lib's that are internal to the glib-2.0-0.dll that I am trying to build

Likewise for the generated gio-2.0.pc:
Libs.private: -lintl -L${libdir} -lgiowin32 -lzlib1 -lintl -lshlwapi -ldnsapi -liphlpapi -lws2_32

Note the part where it says -lgiowin32, which is a static .lib that is internal to the gio-2.0-0.dll that I am trying to build.

These static .lib's get in the way when I try to build items using Meson that depends on these pkg-config files, as these static .lib's would not be found since they won't be installed, so as a workaround I need to remove them from these pkg-config files before I try to build any other projects using Meson that depends on them.

With blessings, and cheers, and thank you!

[nirbheek]

@fanc999 yes, it's the same issue. Can you try the patch in #3939?

[xclaesse]

Should be fixed by #5936