Bazel 5.x support

[keith]

I'm filing this as a tracking issue around bazel 5.x, which should be RC next week bazelbuild/bazel#14013

I've started lightly testing this to see how much work it will be to update. I will update this issue with the issues we find:

• I discovered Label.relative behavior change bazelbuild/bazel#14152, which we have some ways to workaround given the limited use case of genrule_repository today
• It seems the java flags we pass are now outdated, there are some new warnings about the ones we pass being deprecated, and for me builds would fail immediately until I started passing --java_runtime_version=remotejdk_11
• Update build tools image

[htuch]

CC @phlax

[phlax]

im wondering about having a 5.x build container for testing until we are ready to land

maybe it doesnt matter for testing and we can just update everything in the envoy repo/ci - not sure

[phlax]

cc @lizan

[Wyverald]

See #18711 for the first issue

[phlax]

i guess this is the line im most concerned about in the build container https://github.com/envoyproxy/envoy-build-tools/blob/81a93046060dbe5620d5b3aa92632090a9ee4da6/toolchains/regenerate.sh#L5

@keith @Wyverald do you mind if i add "Update build container" to the list of tasks for this ticket ?

[keith]

I haven't looked into how that is built, but I think the .bazelversion file on main is still consulted, so in this attempt envoyproxy/envoy-build-tools#156 it seems to have still downloaded 4.x. Added to todos still

[phlax]

cool, i can raise a PR in envoy-build-tools if you dont...

(EDIT: just read comment better and see there is a PR - can we set a fixed release, im not sure rolling release is desirable as it might change without notice, and i guess updating the .bazelversion also needs to happen)

[keith]

I reopened and pinned to a specific version for now, we'll just have to update it later once the release is out

[keith]

Another small issue: #18730

[phlax]

related: release schedule/blockers for upstream is here https://github.com/bazelbuild/bazel/milestone/31

[keith]

Looking pretty good. I'm not sure what to think about this issue:

==================== Test output for @envoy_api//test/validate:pgv_test:
/b/f/w/bazel-out/k8-fastbuild/bin/external/envoy_api/test/validate/pgv_test.runfiles/envoy/../envoy_api/test/validate/pgv_test: error while loading shared libraries: libexternal_Senvoy_Uapi_Senvoy_Sconfig_Sbootstrap_Sv3_Slibpkg_Ucc_Uproto.so: cannot open shared object file: No such file or directory
================================================================================

I don't see it locally on my linux machine. https://dev.azure.com/cncf/envoy/_build/results?buildId=92616&view=logs&j=b4781dd6-e8d1-56ca-824c-e97e27bdf79d&t=45617383-04d6-5506-f07f-2ba46008d9c7

[keith]

Landed in #19706 (comment)