Update Runfiles usage to fix BCR, bump versions

[mbland]

Description

Fixes the runfiles problems with Windows builds for Bazel 8 and later seen in bazelbuild/bazel-central-registry#5490. Bumps a number of dependencies, and bumps the rules_scala version in MODULE.bazel from 7.1.0 to 7.1.1.

Dependency version bumps include:

• Go: 1.24.5 => 1.25.0
• golang.org/x/tools: v0.35.0 => v0.36.0
• jline: 3.30.4 => 3.30.5
• protobuf-java: 4.31.1 => 4.32.0
• protobuf: v31.1 => v32.0
• rules_java: 8.15.0 => 8.15.1
• rules_python: 1.5.2 => 1.5.3

Also:

• Restores examples/crossbuild/protobuf.patch to a symlink, undoing the change from Fix BCR presubmit, update rules_python to 1.5.2 #1760.

• Fixes precompiled Windows protoc selection on ARM64 in protoc/private/protoc_toolchains.bzl.

• Removes RULES_SCALA_MAIN_WS_NAME from the ScalaTest runner implementation.

• Removes rules_jvm_external from scala/latest_deps.bzl.

Motivation

bazelbuild/continuous-integration#2350 resolved the Windows symlink problem, fixing the bazelbuild/bazel-central-registry#5490 Bazel 7 Windows build. This enables the restoration of the original examples/crossbuild/protobuf.patch symlink, effectively closing bazelbuild/bazel-central-registry#5506.

The src/java/io/bazel/rulesscala/exe/LauncherFileWriter.java changes fix the remaining bazelbuild/bazel-central-registry#5490 breakages. Specifically, adding the .exe suffix only when necessary under Bazel 7 fixes the Windows builds for Bazel 8 and later. However, we'll have to close that pull request and push the v7.1.1 tag to begin a new release.

The updates to use @AutoBazelRepository and Runfiles.preload(), etc. are from the com.google.devtools.build.Runfiles docstring:

• https://github.com/bazelbuild/rules_java/blob/8.15.1/java/runfiles/src/main/java/com/google/devtools/build/runfiles/Runfiles.java#L31-L134

RULES_SCALA_MAIN_WS_NAME is no longer necessary given proper runfiles library usage, and technically became obsolete in commit f758956.

Instantiating rules_jvm_external ourselves is no longer necessary because protobuf v32.0 contains protocolbuffers/protobuf#22225, which closed protocolbuffers/protobuf#19129.

I've tested this change using my personal Windows 11 ARM64 virtual machine, hence the updates to protoc/private/protoc_toolchains.bzl. Previously, the exec_compatible_with attribute of the toolchain target contained @platforms//cpu:x86_64 instead of @platforms//cpu:aarch64. This caused @protobuf//bazel/private:proto_toolchain_type to resolve to @protobuf//bazel/private/toolchains:protoc_sources, triggering recompilation.

I also had to use python.single_version_platform_override and to fix @bazel_tools//tools/jdk:proguard_whitelister on Windows ARM64. This is because the latest rules_python 1.5.3 doesn't contain any entries for aarch64-pc-windows-msvc in //python:versions.bzl.

However, it appears such entries are coming in the next rules_python release, which will eliminate the need for such a workaround. For that reason, I haven't tried to include it in this change.

• https://github.com/bazelbuild/bazel/blob/7.6.1/tools/jdk/BUILD.tools#L133-L138
• https://github.com/bazel-contrib/rules_python/blob/1.5.3/python/versions.bzl
• https://github.com/astral-sh/python-build-standalone/releases/
• https://rules-python.readthedocs.io/en/latest/api/rules_python/python/extensions/python.html#python.single_version_platform_override
• Support Windows on ARM64 rules_python#2276
• feat: Add windows arm64 python toolchains rules_python#3062
• chore: update python toolchains rules_python#3074
• chore(toolchains): start pulling toolchains from 20250808 release rules_python#3116

A couple of interesting new facts I learned about protobuf in the process of producing this change:

• v32.0 officially drops support for Bazel 6:
  https://github.com/protocolbuffers/protobuf/releases/tag/v32.0
  protocolbuffers/protobuf@da0077e

• v34 isn't dropping MSVC support after all:
  https://protobuf.dev/news/2025-07-16/
  [CANCELED] Breaking Change: Dropping support for Bazel+MSVC protocolbuffers/protobuf#20085
  [CANCELED] Breaking Change: Dropping support for Bazel+MSVC protocolbuffers/protobuf#20085 (comment)

[mbland]

@meteorcloudy This fixes the runfiles problem that broke the Windows builds for Bazel 8 and later in bazelbuild/bazel-central-registry#5490 after bazelbuild/continuous-integration#2350 fixed the symlink problem. The Bazel 7 build passed because it generates bazel_tools/tools/launcher/launcher.exe. Bazel 8 and later don't include the .exe extension.

Thought this would be good to know in case any other BCR PRs get bitten by this detail.

[simuons]

Thanks, @mbland! Really appreciated for digging into this.

[mbland]

@simuons My pleasure! Can you push a new v7.1.1 tag to trigger a new BCR pull request? I don't think there's a way for bazelbuild/bazel-central-registry#5490 to pick up this change.

[mbland]

@simuons Actually, can we get #1762 in first, then push v7.1.1?