Error in fail: toolchain target @rules_cc//cc:current_cc_toolchain for 'cc_toolchain' has no files (windows)

[peakschris]

Whilst working on windows support PR, I have hit an issue with cc_toolchain in the examples directory. I am expecting rules_cc to resolve MSVC as BAZEL_VC envvar is set. Updating to latest rules_cc does not help. If anyone can suggest the correct fix I can add it to my PR.

ERROR: D:/workdir/github/peakschris/bazel_env.bzl/examples/BUILD.bazel:18:10: in _toolchain rule //:bazel_env/toolchains/cc_toolchain:
Traceback (most recent call last):
        File "D:/udu/b/ujs5ooev/external/bazel_env.bzl+/bazel_env.bzl", line 382, column 13, in _toolchain_impl
                fail(
Error in fail: toolchain target @rules_cc//cc:current_cc_toolchain for 'cc_toolchain' has no files

--toolchain_resolution_debug=.* returns:

INFO: ToolchainResolution: Performing resolution of @@bazel_tools//tools/cpp:toolchain_type for target platform @@platforms//host:host
      ToolchainResolution:   Rejected toolchain @@rules_cc++cc_configure_extension+local_config_cc//:cc-compiler-arm64_windows; mismatching values: aarch64
      ToolchainResolution:   Rejected toolchain @@rules_cc++cc_configure_extension+local_config_cc//:cc-compiler-armeabi-v7a; mismatching values: armv7, android
      ToolchainResolution:   Toolchain @@rules_cc++cc_configure_extension+local_config_cc//:cc-compiler-x64_windows is compatible with target platform, searching for execution platforms:
      ToolchainResolution:     Compatible execution platform @@platforms//host:host
      ToolchainResolution:     Skipping execution platform @@platforms//host:host; it has already selected a toolchain
      ToolchainResolution:   All execution platforms have been assigned a @@bazel_tools//tools/cpp:toolchain_type toolchain, stopping
      ToolchainResolution: Recap of selected @@bazel_tools//tools/cpp:toolchain_type toolchains for target platform @@platforms//host:host:
      ToolchainResolution:   Selected @@rules_cc++cc_configure_extension+local_config_cc//:cc-compiler-x64_windows to run on execution platform @@platforms//host:host

[fmeum]

I think that this happens since the MSVC toolchains don't generate a compiler wrapper and thus have no files in the execroot. The path for CC may very well be absolute?