[package] opengl/system: cannot be consumed on Linux if pkg-config is not installed

[SpaceIm]

Description

When you consume opengl recipe, there is a call to pkg-config if host is Linux or FreeBSD to fill cpp_info, but pkg-config is not a core package installed by default on these systems, so it may fail.

Package and Environment Details

• Package Name/Version: opengl/system
• Operating System+version: Linux Ubuntu 22.04
• Compiler+version: GCC 12
• Conan version: conan 1.56.0
• Python version: Python 3.10.6

Conan profile

[settings]
os=Linux
arch=x86_64
compiler=gcc
compiler.version=12
compiler.libcxx=libstdc++11
build_type=Release
[options]
[conf]
[build_requires]
[env]

Steps to reproduce

conan install glfw/3.3.8@ -b glfw for example

Logs

Click to expand log

ERROR: opengl/system: Error in package_info() method, line 85
        self._fill_cppinfo_from_pkgconfig('gl')
while calling '_fill_cppinfo_from_pkgconfig', line 24
        if not pkg_config.provides:
        ConanException: pkg-config command ['pkg-config', '--print-provides', 'gl', '--print-errors'] failed with error: Command 'pkg-config --print-provides gl --print-errors' returned non-zero exit status 127.
/bin/sh: 1: pkg-config: not found

[memsharded]

What would be the solution for this? Alternatives:

• Adding a system_requirements() to the recipe, to make sure it is there?
• To add a dependency to a pkg_config/system recipe?
• To remove the pkg_config dependency by hardcoding the information in package_info()? (I guess this will be complicated to maintain for different platforms)

[SpaceIm]

To remove the pkg_config dependency by hardcoding the information in package_info()? (I guess this will be complicated to maintain for different platforms)

Maybe call PkgConfig at package() time, add pkgconf to build_requirements, store the result in a file, then load this file at consume time (of course recipe could not clear self.info anymore, there should be a different package id for Linux, FreeBSD, and a unique package id for all other OS which wouldn't depend on this file).

[SpaceIm]

conan-io/conan#14422