Protobuf cmake build on windows fails on requiring absl targets which are "not in the export set".

[jtattermusch]

(This issue prevents grpc from upgrading to protobuf's 22.x release)

When protobuf is added as a grpc dependency (via cmake's add_subdirectory), it seems that the protobuf cmake build is misconfigured on windows and the build fails with the following error:

CMake Error: install(EXPORT "protobuf-targets" ...) includes target "libprotobuf-lite" which requires target "absl_absl_check" that is not in the export set.
CMake Error: install(EXPORT "protobuf-targets" ...) includes target "libprotobuf-lite" which requires target "absl_absl_log" that is not in the export set.
CMake Error: install(EXPORT "protobuf-targets" ...) includes target "libprotobuf-lite" which requires target "absl_algorithm" that is not in the export set.
CMake Error: install(EXPORT "protobuf-targets" ...) includes target "libprotobuf-lite" which requires target "absl_base" that is not in the export set.
CMake Error: install(EXPORT "protobuf-targets" ...) includes target "libprotobuf-lite" which requires target "absl_bind_front" that is not in the export set.
CMake Error: install(EXPORT "protobuf-targets" ...) includes target "libprotobuf-lite" which requires target "absl_bits" that is not in the export set.
CMake Error: install(EXPORT "protobuf-targets" ...) includes target "libprotobuf-lite" which requires target "absl_btree" that is not in the export set.
...
other similar errors follow.

(On linux the cmake builds seems to work just file). Is there something special about how the absl dependency is added to protobuf on windows that could cause this?

[jtattermusch]

CC @veblush
@deannagarcia @mkruskal-google @perezd can you please take a look? This is one of the issues (there are many) which are preventing gRPC from upgrading to protobuf 22.x

[acozzette]

There is some logic specific to MSVC that could be related. Is there a way we could reproduce the error?

[jtattermusch]

I have some initial evidence that his behavior might be cmake version dependent. The original reproduction was with cmake 3.10 and when I tried with cmake 3.25, I could no longer reproduce. So it seems that this issue might not be a hard blocker for for protobuf upgrade (since our windows workers now have cmake 3.25), but we should investigate this behavior anyway (just not as urgently).

I will post an update here to confirm that I can no longer reproduce on cmake 3.25 once I double check my experiments.

[jtattermusch]

At this point I'm 99% sure that the issue can only be reproduced on older cmake versions (I tried cmake 3.10) and things work fine with newer cmake (I tried 3.25). So this issue is no longer a blocker for grpc's upgrade to 22.x (since our windows workers have new-enough cmake and our tests pass), but we should investigate which cmake version is that last one that's broken and perhaps that would tell us what the issue is (I suspect it's some change in how cmake handles exporting targets?).

I can look into figuring out the last broken cmake version later, but currently I'm too busy trying to finish grpc's protobuf upgrade.

I'm getting the same errors with CMake 3.26.4 when using FetchContent to include the 1.55.0 release of gRPC. I also tried cloning the gRPC repository and running CMake build directly in the repository and that succeeds.

project (my_project)

include(FetchContent)
FetchContent_Declare(
  gRPC
  GIT_REPOSITORY https://github.com/grpc/grpc
  GIT_TAG        v1.55.0
)
set(FETCHCONTENT_QUIET OFF)
FetchContent_MakeAvailable(gRPC)