Work with RBE and --experimental_allow_unresolved_symlinks enabled once Bazel supports it

[gregmagolan]

With #283 landed, rules_js will now use the ctx.actions.declare_symlink API to create all of the symlinks in the symlinks node_modules tree if the --experimental_allow_unresolved_symlinks flag is set.

This feature is not yet stable in Bazel (see bazelbuild/bazel#10298) and is currently being stabilized by @fmeum split across multiple PRs to bazel such as bazelbuild/bazel#15963.

This can slip the 1.0 milestone since it depends on when things land in Bazel. It is here for now for visibility on the roadmap for users.

[mrmeku]

With the 5.3.0 release candidate is this fixed? @gregmagolan

https://groups.google.com/g/bazel-discuss/c/CTrwcVMov0k

[gregmagolan]

It will not. It looks like 6.0 is where they will land. Relevant issue to follow the progress is this one bazelbuild/bazel#10298.

[alexeagle]

With bazelbuild/bazel#15781 landed today, we think
the only remaining issue with Bazel at HEAD preventing rules_js on RBE is bazelbuild/bazel#14224

[alexeagle]

#400 shows that rules_js is now working with RBE at HEAD!

However it requires one change to Bazel which is on this fork: https://github.com/aspect-build/bazel/releases/tag/6.0.0-aspect1

https://github.com/aspect-build/rules_js/blob/main/.github/workflows/ci.yaml#L56 shows where we select our fork for RBE builds on CI.

[alexeagle]

For anyone who wants to try RBE with rules_js or rules_ts now, here are the steps:

1. Decide where you want to enable this. Since there is no release of Bazel which has all the needed fixes (as of this writing) you'll need to use a fork of Bazel. You have to decide if you're okay with the risk of updating your "production" Bazel version that all developers use, or maybe try this out only on a branch, or maybe use the newer Bazel only on CI and not for local development.
2. Use our fork: https://github.com/aspect-build/bazel/releases/tag/6.0.0-aspect1 which currently supports only Linux x86 and MacOS on x86 or Apple Silicon. Use the usual configuration affordances in https://github.com/bazelbuild/bazelisk - for example put USE_BAZEL_VERSION=aspect-build/6.0.0-aspect1 in the environment where bazelisk runs, or put aspect-build/6.0.0-aspect1 in your .bazelversion file
3. Use the newest rules_js release, as we're still making fixes.
4. Pass the --experimental_allow_unresolved_symlinks flag to Bazel when running with RBE.
5. Turn on RBE using Bazel's flags. See https://bazel.build/remote/rbe

[alexeagle]

bazelbuild/bazel#16272 is the PR we expect will fully resolve this, and should make it into Bazel 6.0 :)

[gregmagolan]

bazelbuild/bazel#16272 is landed on master bazelbuild/bazel@d834905

[gregmagolan]

Latest rules_js works with Bazel 6.0.0rc2 with RBE. Closing this issue.