Bazel build broken at main / 7.x

[sgammon]

What version of protobuf and what language are you using?
Version: main
Language: N/A

What operating system (Linux, Windows, ...) and version? N/A

What runtime / compiler are you using (e.g., python version or gcc version)

openjdk version "21.0.2" 2024-01-16
OpenJDK Runtime Environment GraalVM CE 21.0.2+13.1 (build 21.0.2+13-jvmci-23.1-b30)
OpenJDK 64-Bit Server VM GraalVM CE 21.0.2+13.1 (build 21.0.2+13-jvmci-23.1-b30, mixed mode, sharing)

What did you do?
Steps to reproduce the behavior:

1. git clone git@github.com:protocolbuffers/protobuf.git && cd protobuf
2. bazel build //java:release (passes)

What did you expect to see
Passing build

What did you see instead?

➜  protobuf-main git:(main) bazel build //java:release
Starting local Bazel server and connecting to it...
ERROR: /Volumes/VAULTROOM/proto/protobuf-main/java/util/BUILD.bazel:24:32: in _osgi_jar rule //java/util:util_bundle: 
Traceback (most recent call last):
	File "/Volumes/VAULTROOM/proto/protobuf-main/java/osgi/osgi.bzl", line 177, column 48, in _osgi_jar_impl
		source_jar = target_java_output.source_jars[0]
Error: type 'depset' has no operator [](int)
ERROR: /Volumes/VAULTROOM/proto/protobuf-main/java/util/BUILD.bazel:24:32: Analysis of target '//java/util:util_bundle' failed
ERROR: Analysis of target '//java:release' failed; build aborted: Analysis failed
INFO: Elapsed time: 18.330s, Critical Path: 0.01s
INFO: 1 process: 1 internal.
ERROR: Build did NOT complete successfully
Error: bazel exited with exit code: 1

Anything else we should know about your project / environment
I don't see a .bazelversion, so default latest is running via Bazelisk:

Build target: @@//src/main/java/com/google/devtools/build/lib/bazel:BazelServer
Build time: Mon Mar 11 17:55:51 2024 (1710179751)
Build timestamp: 1710179751
Build timestamp as int: 1710179751

Pinning to 6.3.2 fixes the problem:

echo 6.3.2 > .bazelversion

[sgammon]

I've posted two PR fix options for this issue: one which pins the build to 6.3.2, and one which brings the build up to Bazel 7.x support.

• Pin: fix: pin bazel → 6.3.2 #16171
• 7.x: fix: support for bazel 7.x #16172