David Ostrovsky

> What would applying the incompatible change policy look like here, should there be --incompatible_use_version_X_of_toolchain_dependency_Y flags? Just `--incompatible_use_java_tools_version_X` should be enough. `java_tools` has many tools, so that I wouldn't break...

Thanks @brandjon for clarification. I started the attempt to demote two offending checks in recent EP releases to severity level warning, that is disabled in Bazel: [1]. Let's wait and...

FWIW: Gerrit Code Review project added Bazel tool chain for Polymer 3 using `rules_nodejs`. So that this issue can be closed now.

In this PR: https://github.com/bazelbuild/rules_closure/pull/239 I was trying to consume `java_import_external` from Bazel itself, instead of using `rules_closure`'s clone. In upcoming Bazel releases, native `maven_jar` is going to be discontinued anyway....

> Also, the gerrit code review tool, as part of the PolyGerrit UI rewrite, has started adding bazel support for polymer build primitives (cripser and vulcanize) Closure compiler was integrated...

It turns out, that with whitespace optimization level es5_runtime isn't injected per default. Addressed here: [1]. * [1] https://bugs.chromium.org/p/gerrit/issues/detail?id=6110

@jart Do you think gerrit code review could use `rules_closure` with tensorboard rules to use advanced optimization level on Polymer 1? We are using still `WHITESPACE_ONLY` mode, unfortunately. https://github.com/GerritCodeReview/gerrit/blob/master/polygerrit-ui/app/rules.bzl#L17

Gerrit Code Review project has the same issue. After bumping `bazel-toolchain` from 5.0.0 to 5.1.0 we are getting this error: ``` $ bazel build --config=remote --remote_instance_name=projects/api-project-164060093628/instances/default_instance headless INFO: Invocation ID:...

> Do you mean 4.0.0 to 5.1.0? Because from 5.0.0 to 5.1.0 should be no breaking change. No. I mean what I said: 5.0.0 to 5.1.0. We are currently using...

This is the CL: [1] from February 2021, where I bumped bazel-toolchain to 5.0.0 in Gerrit Code Review project. [1] https://gerrit-review.googlesource.com/c/gerrit/+/296769