Invalid formatting of libdir/includedir in pkg_config generator [bug]

[coffee-lord]

Version: conan-1.2.3
OS: Linux

conan/conans/client/generators/pkg_config.py

Lines 28 to 36 in ac25c89

	for i, libdir in enumerate(cpp_info.libdirs):
	varname = "libdir" if i == 0 else "libdir%d" % (i + 2)
	lines.append("%s=${prefix}/%s" % (varname, libdir))
	libdir_vars.append(varname)
	include_dir_vars = []
	for i, includedir in enumerate(cpp_info.includedirs):
	varname = "includedir" if i == 0 else "includedir%d" % (i + 2)
	lines.append("%s=${prefix}/%s" % (varname, includedir))
	include_dir_vars.append(varname)

pkg_config generator doesn't check if libdir or includedir are absolute paths which leads to the following (invalid) .pc being generated for boost_math/1.66.0@bincrafters/stable:

prefix=/home/user/.conan/data/boost_math/1.66.0/bincrafters/stable/package/937af278b1c9d86290dddaf1322dc99fb7d75862
libdir=${prefix}//home/user/.conan/data/boost_level8group/1.66.0/bincrafters/stable/package/afc149253b16bde7d64e527e0dbfa27b203330c8/math/lib
includedir=${prefix}//home/user/.conan/data/boost_level8group/1.66.0/bincrafters/stable/package/afc149253b16bde7d64e527e0dbfa27b203330c8/math/include
...

[danimtb]

Hi @coffee-lord !

Thanks you so much fot the detailed report. Seems it is a bug with absolute paths as you said, mainly affecting recipes with short_paths=True like boost ones.

We will try to fix it for the next release.
Thanks!

[danimtb]

Seems the bug has nothing to do with short_paths=True and it is only related to the ${prefix} prepending in the pkg_config generator.

[coffee-lord]

@danimtb While we're on the subject, pkg_config generator also doesn't emit -Wl,-rpath= flags. Is that intentional?

[danimtb]

Hi @coffee-lord

Yes, those flags are missing from the logic of the generator. Let's update it with those flags now that we have a PR open for this.

Thanks!

[coffee-lord]

With regards to #2797:

1. -L${libdir} is added unconditionally

conan/conans/client/generators/pkg_config.py

Lines 45 to 48 in 8f9f564

	varname = "libdir"
	dir_lines = _generate_dir_lines(prefix_path, varname, cpp_info.libdirs)
	libdir_vars.append(varname)
	lines.extend(dir_lines)

Which leads to "Variable 'libdir' not defined" error in pkg-config when dir_lines is empty.

prefix=...
includedir=...

Name: boost_conversion
Description: Conan package: boost_conversion
Version: 1.66.0
Libs: -L${libdir} ...

2. Irrelevant rpaths

It seems that pkg_config generator outputs rpaths of all dependencies which makes the list of compiler arguments exponentially long. I don't think we need to include rpaths of dependencies at all. -L${libdir} -Wl,-rpath${libdir} for each libdir should be enough.

Relevant package: boost_conversion/1.66.0@bincrafters/stable

@memsharded

[memsharded]

Yes, the first thing is certainly a bug. Will be solved as soon as possible.
Also, the second observation is relevant too, lets try to improve it also.

Many thanks for your early and detailed feedback!