Conan-center-index: [question] protobuf: Add components

[joxoby]

Hi everyone,

I'm trying to add components to the protobuf recipe but I'm not being able to pass the tests. The default FindProtobuf.cmake exports several components:

The following :prop_tgt:`IMPORTED` targets are also defined:

``protobuf::libprotobuf``
  The protobuf library.
``protobuf::libprotobuf-lite``
  The protobuf lite library.
``protobuf::libprotoc``
  The protoc library.
``protobuf::protoc``
  The protoc compiler.

The definition of package_info() in the current recipe of protobuf/3.11.4 is:

def package_info(self):
    self.cpp_info.libs = tools.collect_libs(self)
    self.cpp_info.libs.sort(reverse=True)

    if self.settings.os == "Linux":
        self.cpp_info.system_libs.append("pthread")
        if self._is_clang_x86 or "arm" in str(self.settings.arch):
            self.cpp_info.system_libs.append("atomic")

    if self.settings.os == "Windows":
        if self.options.shared:
            self.cpp_info.defines = ["PROTOBUF_USE_DLLS"]
    self.cpp_info.names["cmake_find_package"] = "Protobuf"
    self.cpp_info.names["cmake_find_package_multi"] = "Protobuf"
    self.cpp_info.builddirs = [
        self._cmake_install_base_path,
    ]
    self.cpp_info.build_modules = [
        os.path.join(self._cmake_install_base_path, "protobuf-generate.cmake"),
        os.path.join(self._cmake_install_base_path, "protobuf-module.cmake"),
        os.path.join(self._cmake_install_base_path, "protobuf-options.cmake"),
    ]
    bindir = os.path.join(self.package_folder, "bin")
    self.output.info("Appending PATH environment variable: {}".format(bindir))
    self.env_info.PATH.append(bindir)

I'm trying to change it to:

def package_info(self):
    self.cpp_info.names["cmake_find_package"] = "Protobuf"
    self.cpp_info.names["cmake_find_package_multi"] = "Protobuf"

    # Component libprotobuf
    self.cpp_info.components["libprotobuf"].libs = ["libprotobuf"]
    if self.settings.os == "Linux":
        self.cpp_info.components["libprotobuf"].system_libs.append("pthread")
        if self._is_clang_x86 or "arm" in str(self.settings.arch):
            self.cpp_info.components["libprotobuf"].append("atomic")

    if self.settings.os == "Windows":
        if self.options.shared:
            self.cpp_info.components["libprotobuf"].defines = ["PROTOBUF_USE_DLLS"]

    # Component libprotoc
    self.cpp_info.components["libprotoc"].libs = ["libprotoc"]

    # Component protoc
    # How to add an executable?
    if not self.options.lite:
        self.cpp_info.components["protoc"].libs = ["libprotoc"]

    # Should this be the same for libprotoc
    self.cpp_info.components["libprotobuf"].builddirs = [
        self._cmake_install_base_path,
    ]
    self.cpp_info.components["libprotobuf"].build_modules = [
        os.path.join(self._cmake_install_base_path, "protobuf-generate.cmake"),
        os.path.join(self._cmake_install_base_path, "protobuf-module.cmake"),
        os.path.join(self._cmake_install_base_path, "protobuf-options.cmake"),
    ]

    bindir = os.path.join(self.package_folder, "bin")
    self.output.info("Appending PATH environment variable: {}".format(bindir))
    self.env_info.PATH.append(bindir)

Does this seem reasonable?

When creating the package, the testing fails with:

Using lockfile: '/home/juan/conan-center-index/recipes/protobuf/all/test_package/build/8e7da137254ca61c29cfd61de2482b72ba0ff99c/conan.lock'
Using cached profile from lockfile
protobuf/3.11.4@juan/test (test package): Calling build()
-- The C compiler identification is GNU 8.3.0
-- The CXX compiler identification is GNU 8.3.0
-- Detecting C compiler ABI info
-- Detecting C compiler ABI info - done
-- Check for working C compiler: /usr/bin/cc - skipped
-- Detecting C compile features
-- Detecting C compile features - done
-- Detecting CXX compiler ABI info
-- Detecting CXX compiler ABI info - done
-- Check for working CXX compiler: /usr/bin/c++ - skipped
-- Detecting CXX compile features
-- Detecting CXX compile features - done
-- Conan: called by CMake conan helper
-- Conan: Adjusting output directories
-- Conan: Using cmake global configuration
-- Conan: Adjusting default RPATHs Conan policies
-- Conan: Adjusting language standard
-- Conan: Compiler GCC>=5, checking major version 8
-- Conan: Checking correct version: 8
-- Conan: C++ stdlib: libstdc++11
-- Configuring done
-- Generating done
CMake Warning:
  Manually-specified variables were not used by the project:

    CMAKE_EXPORT_NO_PACKAGE_REGISTRY


-- Build files have been written to: /home/juan/conan-center-index/recipes/protobuf/all/test_package/build/8e7da137254ca61c29cfd61de2482b72ba0ff99c/without_protoc
/usr/local/bin/cmake -S/home/juan/conan-center-index/recipes/protobuf/all/test_package -B/home/juan/conan-center-index/recipes/protobuf/all/test_package/build/8e7da137254ca61c29cfd61de2482b72ba0ff99c/without_protoc --check-build-system CMakeFiles/Makefile.cmake 0
/usr/local/bin/cmake -E cmake_progress_start /home/juan/conan-center-index/recipes/protobuf/all/test_package/build/8e7da137254ca61c29cfd61de2482b72ba0ff99c/without_protoc/CMakeFiles /home/juan/conan-center-index/recipes/protobuf/all/test_package/build/8e7da137254ca61c29cfd61de2482b72ba0ff99c/without_protoc//CMakeFiles/progress.marks
/usr/bin/make -s -f CMakeFiles/Makefile2 all
Scanning dependencies of target test_package
[ 33%] Building CXX object CMakeFiles/test_package.dir/test_package.cpp.o
[ 66%] Building CXX object CMakeFiles/test_package.dir/addressbook.pb.cc.o
[100%] Linking CXX executable bin/test_package
/usr/bin/ld: cannot find -llibprotobuf
/usr/bin/ld: cannot find -llibprotoc
collect2: error: ld returned 1 exit status
CMakeFiles/test_package.dir/build.make:118: recipe for target 'bin/test_package' failed
make[2]: *** [bin/test_package] Error 1
CMakeFiles/Makefile2:95: recipe for target 'CMakeFiles/test_package.dir/all' failed
make[1]: *** [CMakeFiles/test_package.dir/all] Error 2
Makefile:103: recipe for target 'all' failed
make: *** [all] Error 2

Any ideas? Thanks for the help.

[Croydon]

See also https://github.com/conan-io/conan-center-index/pull/2037

[joxoby]

@Croydon thank you. Closing this issue.

[uilianries]

I should provide component today or next yet. Finally we all support from Conan to generate the correct targets and variables. Protobuf is kind of exotic in terms of cmake