protobuf.pc pkgconfig file generated by protobuf's cmake build doesn't declare absl and utf8_range dependencies.

[jtattermusch]

Starting from 22.x, protobuf now depends on absl and utf8_range, but the protobuf.pc pkgconfig file doesn't properly declare those dependencies.
As a result, the build is broken if someone installs protobuf and then wants to include it via pkgconfig (since they'd be missing absl and utf8_validity symbols when trying to link).

See https://github.com/protocolbuffers/protobuf/blob/f11079b01f075bc7c5b3286d85a8feca798c09e9/cmake/protobuf.pc.cmake

This issue breaks grpc's build-and-install "distribtest" that tries to build helloworld example with grpc and protobuf:
https://github.com/grpc/grpc/blob/24d83cda9bb1caaff9c03ace6f418e946e88c49d/examples/cpp/helloworld/Makefile#L28
(which runs pkgconfig to get a list of libraries to link against when building a project that depends on grpc++ and protobuf).

[jtattermusch]

CC @deannagarcia @mkruskal-google I have a dirty workaround I can use in our distribtests so fixing this isn't a strict blocker for grpc's protobuf 22.x upgrade, but of course this is something that still needs to be fixed in order for building via pkgconfig to become clean again.

[mmjkelso]

I have run into this trying to build grpc . In the grpc cmake build I'm declaring gRPC_PROTOBUF_PROVIDER=package and pointing Protobuf_DIR to the part of the protobuf install with the protobuf-config.cmake file. When the grpc config gets up to the protobuf part it fails saying the protobuf is marked as not found due to missing utf8_range dependency.

What workarounds are there ? I'm trying various thing but no luck so far.

Edit: actually I don't know if this is the same pkgconfig problem, but it seems related.

[jtattermusch]

I have run into this trying to build grpc . In the grpc cmake build I'm declaring gRPC_PROTOBUF_PROVIDER=package and pointing Protobuf_DIR to the part of the protobuf install with the protobuf-config.cmake file. When the grpc config gets up to the protobuf part it fails saying the protobuf is marked as not found due to missing utf8_range dependency.

What workarounds are there ? I'm trying various thing but no luck so far.

Edit: actually I don't know if this is the same pkgconfig problem, but it seems related.

You can use the gRPC's "distribtests" as a reference for what cmake flags/options you need to use to successfully build under different scenarios: https://github.com/grpc/grpc/tree/master/test/distrib/cpp (choose script that best matches your use case) Hope that helps.

[ejona86]

This is impacting grpc-java as well (for the protoc plugin). Absl has an incredible 83 libraries, each with their own separate .pc. Although this will only solve our build on Linux, I'm still uncertain how we'll handle this many libraries on Windows.

[ejona86]

@mkruskal-google, this still seems broken.

When building on 344f6de:

/usr/bin/ld: /tmp/protobuf-cache/main/Linux-x86_64/lib/libprotobuf.a(generated_message_tctable_lite.cc.o): in function `google::protobuf::internal::TcParser::FastSS1(google::protobuf::MessageLite*, char const*, google::protobuf::internal::ParseContext*, google::protobuf::internal::TcFieldData, google::protobuf::internal::TcParseTableBase const*, unsigned long)':
generated_message_tctable_lite.cc:(.text+0x123d0): undefined reference to `utf8_range::IsStructurallyValid(std::basic_string_view<char, std::char_traits<char> >)'
...

Manually adding -lutf8_validity fixes my build, and it is missing from protobuf:

$ pkg-config --libs-only-l protobuf
-lprotobuf -labsl_log_internal_check_op -labsl_leak_check -labsl_die_if_null -labsl_log_internal_conditions -labsl_log_internal_message -labsl_examine_stack -labsl_log_internal_format -labsl_log_internal_proto -labsl_log_internal_nullguard -labsl_log_internal_log_sink_set -labsl_log_sink -labsl_log_entry -labsl_flags -labsl_flags_internal -labsl_flags_marshalling -labsl_flags_reflection -labsl_flags_private_handle_accessor -labsl_flags_commandlineflag -labsl_flags_commandlineflag_internal -labsl_flags_config -labsl_flags_program_name -labsl_log_initialize -labsl_log_globals -labsl_log_internal_globals -labsl_hash -labsl_city -labsl_low_level_hash -labsl_raw_hash_set -labsl_hashtablez_sampler -labsl_statusor -labsl_status -labsl_cord -labsl_cordz_info -labsl_cord_internal -labsl_cordz_functions -labsl_exponential_biased -labsl_cordz_handle -labsl_crc_cord_state -labsl_crc32c -labsl_crc_internal -labsl_crc_cpu_detect -labsl_bad_optional_access -labsl_str_format_internal -labsl_strerror -labsl_synchronization -labsl_graphcycles_internal -labsl_stacktrace -labsl_symbolize -labsl_debugging_internal -labsl_demangle_internal -labsl_malloc_internal -labsl_time -labsl_civil_time -labsl_time_zone -labsl_bad_variant_access -lprotobuf-lite -labsl_strings -labsl_strings_internal -lrt -labsl_base -labsl_spinlock_wait -labsl_int128 -labsl_throw_delegate -labsl_raw_logging_internal -labsl_log_severity

Looks like the problem is utf8_range doesn't add its library:

$ pkg-config --libs-only-l utf8_range 
-lprotobuf-lite -labsl_strings -labsl_strings_internal -lrt -labsl_base -labsl_spinlock_wait -labsl_int128 -labsl_throw_delegate -labsl_raw_logging_internal -labsl_log_severity

[mkruskal-google]

Whoops, that's what I get for copy pasting >.<! That -lprotobuf-lite was supposed to be -lutf8_range. I'll send out a fix ASAP