[bug] PkgConfigDeps fails in generate() (Conan 1)

[db4]

Environment details

• Conan version: 1.62.0

Steps to reproduce

Unpack the attached archive and run build.bat. BTW, Conan 2 doesn't suffer from that.
test_case.zip

Logs

U:\Work\conan_test\override>conan create pkg2.py pkg2/1.0@  --build missing 
Conan 1 is on a deprecation path, please consider migrating to Conan 2
Exporting package recipe
pkg2/1.0: The stored package has not changed
pkg2/1.0: Using the exported files summary hash as the recipe revision: e303c7731dd0a637598b9e4f19459095 
pkg2/1.0: Exported revision: e303c7731dd0a637598b9e4f19459095
Configuration:
[settings]
arch=x86_64
arch_build=x86_64
build_type=Release
compiler=Visual Studio
compiler.runtime=MD
compiler.version=15
os=Windows
os_build=Windows
[options]
[build_requires]
[env]

Installing package: pkg2/1.0
Requirements
    pkg2/1.0 from local cache - Cache
    zlib/1.2.13 from 'conancenter' - Cache
Packages
    pkg2/1.0:606fdb601e335c2001bdf31d478826b644747077 - Cache
    zlib/1.2.13:6cc50b139b9c3d27b3e9042d5f5372d327b3a9f7 - Cache

Installing (downloading, building) binaries...
zlib/1.2.13: Already installed!
pkg2/1.0: Already installed!

U:\Work\conan_test\override>conan create pkg2.py pkg2/1.0+private@ 
Conan 1 is on a deprecation path, please consider migrating to Conan 2
Exporting package recipe
pkg2/1.0+private: The stored package has not changed
pkg2/1.0+private: Using the exported files summary hash as the recipe revision: e303c7731dd0a637598b9e4f19459095 
pkg2/1.0+private: Exported revision: e303c7731dd0a637598b9e4f19459095
Configuration:
[settings]
arch=x86_64
arch_build=x86_64
build_type=Release
compiler=Visual Studio
compiler.runtime=MD
compiler.version=15
os=Windows
os_build=Windows
[options]
[build_requires]
[env]

pkg2/1.0+private: Forced build from source
Installing package: pkg2/1.0+private
Requirements
    pkg2/1.0+private from local cache - Cache
    zlib/1.2.13 from 'conancenter' - Cache
Packages
    pkg2/1.0+private:606fdb601e335c2001bdf31d478826b644747077 - Build
    zlib/1.2.13:6cc50b139b9c3d27b3e9042d5f5372d327b3a9f7 - Cache

Installing (downloading, building) binaries...
zlib/1.2.13: Already installed!
pkg2/1.0+private: Applying build-requirement: zlib/1.2.13
pkg2/1.0+private: Copying sources to build folder
pkg2/1.0+private: Building your package in D:\.conan\data\pkg2\1.0+private\_\_\build\606fdb601e335c2001bdf31d478826b644747077
pkg2/1.0+private: Generator txt created conanbuildinfo.txt
pkg2/1.0+private: Aggregating env generators
pkg2/1.0+private: Calling build()
pkg2/1.0+private: WARN: This conanfile has no build step
pkg2/1.0+private: Package '606fdb601e335c2001bdf31d478826b644747077' built
pkg2/1.0+private: Build folder D:\.conan\data\pkg2\1.0+private\_\_\build\606fdb601e335c2001bdf31d478826b644747077
pkg2/1.0+private: Generated conaninfo.txt
pkg2/1.0+private: Generated conanbuildinfo.txt
pkg2/1.0+private: Generating the package
pkg2/1.0+private: Package folder D:\.conan\data\pkg2\1.0+private\_\_\package\606fdb601e335c2001bdf31d478826b644747077
pkg2/1.0+private: Calling package()
pkg2/1.0+private: WARN: This conanfile has no package step
pkg2/1.0+private package(): WARN: No files in this package!
pkg2/1.0+private: Package '606fdb601e335c2001bdf31d478826b644747077' created
pkg2/1.0+private: Created package revision 3e7d88b7fb07aa9c5711d05fd56e7620

U:\Work\conan_test\override>conan create pkg1.py pkg1/1.0@ 
Conan 1 is on a deprecation path, please consider migrating to Conan 2
Exporting package recipe
pkg1/1.0: The stored package has not changed
pkg1/1.0: Using the exported files summary hash as the recipe revision: dd32f861b50f614ceccc73803976f9b7 
pkg1/1.0: Exported revision: dd32f861b50f614ceccc73803976f9b7
Configuration:
[settings]
arch=x86_64
arch_build=x86_64
build_type=Release
compiler=Visual Studio
compiler.runtime=MD
compiler.version=15
os=Windows
os_build=Windows
[options]
[build_requires]
[env]

pkg1/1.0: Forced build from source
Installing package: pkg1/1.0
Requirements
    pkg1/1.0 from local cache - Cache
    pkg2/1.0 from local cache - Cache
    zlib/1.2.13 from 'conancenter' - Cache
Packages
    pkg1/1.0:b6717885bde1a6f867ba42aad86b8ee46fdde182 - Build
    pkg2/1.0:606fdb601e335c2001bdf31d478826b644747077 - Cache
    zlib/1.2.13:6cc50b139b9c3d27b3e9042d5f5372d327b3a9f7 - Cache

Installing (downloading, building) binaries...
zlib/1.2.13: Already installed!
pkg2/1.0: Already installed!
pkg1/1.0: Copying sources to build folder
pkg1/1.0: Building your package in D:\.conan\data\pkg1\1.0\_\_\build\b6717885bde1a6f867ba42aad86b8ee46fdde182
pkg1/1.0: Generator txt created conanbuildinfo.txt
pkg1/1.0: Aggregating env generators
pkg1/1.0: Calling build()
pkg1/1.0: WARN: This conanfile has no build step
pkg1/1.0: Package 'b6717885bde1a6f867ba42aad86b8ee46fdde182' built
pkg1/1.0: Build folder D:\.conan\data\pkg1\1.0\_\_\build\b6717885bde1a6f867ba42aad86b8ee46fdde182
pkg1/1.0: Generated conaninfo.txt
pkg1/1.0: Generated conanbuildinfo.txt
pkg1/1.0: Generating the package
pkg1/1.0: Package folder D:\.conan\data\pkg1\1.0\_\_\package\b6717885bde1a6f867ba42aad86b8ee46fdde182
pkg1/1.0: Calling package()
pkg1/1.0: WARN: This conanfile has no package step
pkg1/1.0 package(): WARN: No files in this package!
pkg1/1.0: Package 'b6717885bde1a6f867ba42aad86b8ee46fdde182' created
pkg1/1.0: Created package revision eb0dee989f9c7f1fe6bd6ae0dcad8724

U:\Work\conan_test\override>conan install . -if build --build missing 
Conan 1 is on a deprecation path, please consider migrating to Conan 2
Configuration:
[settings]
arch=x86_64
arch_build=x86_64
build_type=Release
compiler=Visual Studio
compiler.runtime=MD
compiler.version=15
os=Windows
os_build=Windows
[options]
[build_requires]
[env]

WARN: pkg1/1.0: requirement pkg2/1.0 overridden by your conanfile to pkg2/1.0+private 
conanfile.py: Installing package
Requirements
    pkg1/1.0 from local cache - Cache
    pkg2/1.0+private from local cache - Cache
    zlib/1.2.13 from 'conancenter' - Cache
Packages
    pkg1/1.0:b6717885bde1a6f867ba42aad86b8ee46fdde182 - Cache
    pkg2/1.0+private:606fdb601e335c2001bdf31d478826b644747077 - Cache
    zlib/1.2.13:6cc50b139b9c3d27b3e9042d5f5372d327b3a9f7 - Skip

Installing (downloading, building) binaries...
pkg2/1.0+private: Already installed!
pkg1/1.0: Already installed!
conanfile.py: Generator txt created conanbuildinfo.txt
conanfile.py: Calling generate()
ERROR: conanfile.py: Error in generate() method, line 14
	pc.generate()
	AttributeError: 'NoneType' object has no attribute 'includedirs'

[memsharded]

Hi @db4

Thanks for your report. It seems the new PkgConfigDeps is not playing well with the legacy "private" requirement attribute, that has been replaced by visible=False in Conan 2.0, and by not processing it it is producing some errors.

I don't know how difficult this could be to fix, but lets give it a try.

[db4]

@memsharded
Many thanks for looking into this. Unfortunately due to some legacy recipes, I cannot immediately switch to Conan 2.0 (although I'm moving this way). I've done some debugging and can say that the problem occurs when the graph contains a "skipped" node:

zlib/1.2.13:6cc50b139b9c3d27b3e9042d5f5372d327b3a9f7 - Skip

It's not possible to access cpp_info attribute for such a node (AttributeError("'NoneType' object has no attribute 'includedirs'") will be raised), so maybe this isn't only specific to PkgConfigDeps? Maybe "skipped" dependencies should not be included in dependencies.direct_host values? (currently, they are).
AttributeError exception is raised here:

conan/conan/tools/gnu/pkgconfigdeps.py

Line 40 in 2a77f83

pkg_name = dep.cpp_info.get_property("pkg_config_name") or _get_package_reference_name(dep)

[franramirez688]

Hi @db4

The issue was solved by #15320

It'll be released in the next Conan 1.63 😄