pkg-config does not include required components from dependencies

[azeey]

Environment

• OS Version: Ubuntu 24.04
• Source or binary build? gz-utils3

Description

• Expected behavior: The pkg-config file generated for a project to include required components from dependencies.
• Actual behavior: The generated file only includes the required core library of the dependency, but not any additional required components

Steps to reproduce

1. Add the line

   gz_find_package(gz-utils3 REQUIRED COMPONENTS log)

   Right before gz_configure_build in https://github.com/gazebosim/gz-cmake/blob/3b33067c07460f95af3cbebfff76bdcff4e2d5fe/examples/core_nodep/CMakeLists.txt#L7

2. Assuming you have gz-utils3-log installed, build project and read the contents of cmake/pkgconfig/gz-core_no_deps.pc in the build directory. You should see

   
   prefix=${pcfiledir}/../../
   libdir=${prefix}/lib
   includedir=${prefix}/include/gz/core_no_deps0

Name: Gazebo core_no_deps Description: A set of core_no_deps classes for robot applications Version: 0.1.0 Requires: gz-cmake4 >= 1.1 gz-utils3 Requires.private: Libs: -L${libdir} -lgz-core_no_deps Libs.private: CFlags: -I${includedir} -std=c++11

In the `Requires` clause, there is `gz-utils3`, but not `gz-utils3-log`.

[scpeters]

I noticed this too. I think the fix needs to be in the following lines of gz-config.cmake.in:

• gz-config.cmake.in:151-168

gz_pkg_config_entry is called once with the package name, but we should collect the names of required components and include those as well in a space-separated string (like gz-utils3 gz-utils3-log). This could be done by:

• adding a gz_pkg_config_append_entry macro and calling that within the component for loop
• or constructing the space-separated list of requirements in the for loop and moving the call to gz_pkg_config_entry after the for loop

[scpeters]

potential fix in https://github.com/gazebosim/gz-cmake/pull/451

[azeey]

Per our discussion in the PMC meeting, we should remove pkg-config support from gz-cmake since it's not used anywhere in our code base and most users are probably not using it.