Build failure on Darwin

[justinseinlin]

Answering these questions before submitting your bug report will help us give you a quicker answer. Thank you!

If one or more of these questions are not applicable, feel free to remove them.

Does this issue affect the google-cloud-cpp-spanner project?

Yes

What version of google-cloud-cpp-spanner are you using?

c35a64a

What compiler and version are you using?

Configured with: --prefix=/Applications/Xcode.app/Contents/Developer/usr --with-gxx-include-dir=/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk/usr/include/c++/4.2.1
Apple clang version 11.0.0 (clang-1100.0.33.8)
Target: x86_64-apple-darwin18.7.0
Thread model: posix
InstalledDir: /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin

What operating system and version are you using?

macOS Mojave

What were you trying to do?

bazel build ...

What did you expect to see?

Build successful.

What did you see instead?

ERROR: /private/var/tmp/_bazel_justinlin/99bb0419eafc27d481e255d985fdfff4/external/com_github_grpc_grpc/BUILD:353:1: Linking of rule '@com_github_grpc_grpc//:grpc++' failed (Exit 1) cc_wrapper.sh failed: error executing command external/local_config_cc/cc_wrapper.sh -lc++ -fobjc-link-runtime -Wl,-S -shared -o bazel-out/darwin-fastbuild/bin/external/com_github_grpc_grpc/libgrpc++.so ... (remaining 14 argument(s) skipped)

Use --sandbox_debug to see verbose messages from the sandbox
ld: illegal thread local variable reference to regular symbol __ZN9grpc_core26ApplicationCallbackExecCtx18callback_exec_ctx_E for architecture x86_64
clang: error: linker command failed with exit code 1 (use -v to see invocation)

Anything else you would like us to know?

Bazel version: 1.0.1

[coryan]

Try adding --copt=-DGRPC_BAZEL_BUILD to your Bazel build line, gRPC requires this to build on macOS.

[coryan]

Thanks for filing a detailed bug report. As you can see we changed the .bazelrc file to automatically add this flag when compiling google-cloud-cpp-spanner, but please note (as the documentation now says) that you need the same flag in your own .bazelrc file. There are links to the root cause (bazelbuild/bazel#4341) in the documentation in case you are interested.