Bazel incompatible changes

[laurentlb]

Based on our latest CI run (https://buildkite.com/bazel/bazelisk-plus-incompatible-flags/builds/28#7292f5b2-bd4a-4183-9ed8-819c84282ee6), migration is needed for the following flags:

• --incompatible_depset_is_not_iterable
• --incompatible_depset_union
• --incompatible_disallow_legacy_py_provider
• --incompatible_new_actions_api

Can you please take a look and report any problem with it?

[pmbethe09]

that fails
ERROR: /usr/local/google/home/pbethe/golang/src/github.com/bazelbuild/rules_appengine/test/java/BUILD:3:1: in appengine_war_base rule //test/java:test-war:
Traceback (most recent call last):
File "/usr/local/google/home/pbethe/golang/src/github.com/bazelbuild/rules_appengine/test/java/BUILD", line 3
appengine_war_base(name = 'test-war')
File "/usr/local/google/home/pbethe/golang/src/github.com/bazelbuild/rules_appengine/appengine/java_appengine.bzl", line 150, in _war_impl
_collect_transitive_runtime_deps_for(ctxt.attr.jars)
File "/usr/local/google/home/pbethe/golang/src/github.com/bazelbuild/rules_appengine/appengine/java_appengine.bzl", line 121, in _collect_transitive_runtime_deps_for
transitive_runtime_deps += dep.files
+ operator on a depset is forbidden. See https://docs.bazel.build/versions/master/skylark/depsets.html for recommendations. Use --incompatible_depset_union=false to temporarily disable this check.
ERROR: Analysis of target '//test/java:test-war' failed; build aborted: Analysis of target '//test/java:test-war' failed; build aborted

[pmbethe09]

@laurentlb how do you fix depset += ?

[laurentlb]

General documentation: https://docs.bazel.build/versions/master/skylark/depsets.html
More specifically, see Hanwen's comment and mine: bazelbuild/bazel#5817 (comment)

[pmbethe09]

OK -- I have the java rules working, but the py rules trip on --incompatible_disallow_legacy_py_provider

[laurentlb]

incompatible_disallow_legacy_py_provider is pretty new. You can comment on bazelbuild/bazel#7298 for advice.
If you fixed the other issues, that's already a nice improvement.

[brandjon]

I mailed #99 for --incompatible_disallow_legacy_py_provider (before I saw this thread).

[fejta]

Can we get a new tag? 0.0.8 is the latest and uses a bunch of unsupported bazel functionality

[pmbethe09]

Should we tag as-is, or make changes to appengine/BUILD to deal with the toolchain related warnings?

[fejta]

fdbce05 seems to work with bazel 0.24.0

https://github.com/kubernetes/test-infra/blob/098e7f1727229bcc2602ae5f5f99a646e9bb5217/WORKSPACE#L476-L482

so tagging master HEAD as 0.0.9 or whatever sgtm

[pmbethe09]

Done. 0.0.9 created from head