Windows tests that require protoc are failing in CI

[jayconrod]

For example: https://buildkite.com/bazel/rules-go-golang/builds/2117#f1a36175-f7c1-4cc4-bf93-6ccfc57a428d

(21:45:54) ERROR: C:/b/5nywwchv/external/com_google_protobuf/BUILD:311:2: Couldn't build file external/com_google_protobuf/source_context_proto-descriptor-set.proto.bin: Generating Descriptor Set proto_library @com_google_protobuf//:source_context_proto failed (Exit -1073741515): protoc.exe failed: error executing command
--
  | cd C:/b/5nywwchv/execroot/io_bazel_rules_go
  | SET PATH=C:\tools\msys64\usr\bin;C:\tools\msys64\bin;C:\Windows;C:\Windows\System32;C:\Windows\System32\WindowsPowerShell\v1.0;C:\python3\lib\site-packages\pywin32_system32;C:\python3\Scripts\;C:\python3\;C:\python2\;C:\python2\Scripts;C:\Windows\system32;C:\Windows;C:\Windows\System32\Wbem;C:\Windows\System32\WindowsPowerShell\v1.0\;C:\Windows\System32\OpenSSH\;C:\ProgramData\GooGet;C:\Program Files\Google\Compute Engine\metadata_scripts;C:\Program Files (x86)\Google\Cloud SDK\google-cloud-sdk\bin;C:\Program Files\Google\Compute Engine\sysprep;C:\ProgramData\chocolatey\bin;C:\Program Files\LLVM\bin;C:\tools\msys64\usr\bin;C:\Program Files\Git\cmd;c:\openjdk\bin;C:\Program Files\CMake\bin;c:\ninja;c:\bazel;c:\buildkite
  | SET RUNFILES_MANIFEST_ONLY=1
  | bazel-out/host/bin/external/com_google_protobuf/protoc.exe --proto_path=bazel-out/x64_windows-opt-exec-A2178B74/bin/external/com_google_protobuf/_virtual_imports/source_context_proto --descriptor_set_out=bazel-out/x64_windows-opt-exec-A2178B74/bin/external/com_google_protobuf/source_context_proto-descriptor-set.proto.bin -Igoogle/protobuf/source_context.proto=bazel-out/x64_windows-opt-exec-A2178B74/bin/external/com_google_protobuf/_virtual_imports/source_context_proto/google/protobuf/source_context.proto --direct_dependencies google/protobuf/source_context.proto --direct_dependencies_violation_msg=%s is imported, but @com_google_protobuf//:source_context_proto doesn't directly depend on a proto_library that 'srcs' it. bazel-out/x64_windows-opt-exec-A2178B74/bin/external/com_google_protobuf/_virtual_imports/source_context_proto/google/protobuf/source_context.proto
  | Execution platform: @io_bazel_rules_go//go/toolchain:windows_amd64_cgo

I think the problem here is that protoc.exe is built with the mingw-gcc toolchain, and when it's invoked in proto_library, it's not able to load a .dll. Not sure which file is missing or where it's located. --action_env=PATH should take care of it, but I'm not sure if that's getting passed down to the action.

[adamyi]

I'm running into this issue as well trying to port my code to windows

[jayconrod]

@adamyi I don't think I've seen this issue outside of CI. Please open a new issue, including your environment and command used to invoke Bazel.