fix: index java_proto_library classes in IDE

[tboernerapex]

This should be merged after #391

Summary

java_proto_library rules apply a proto toolchain configuration transition, so their class jars are built in a -ST-<hash> output directory (e.g. darwin_arm64-fastbuild-ST-8c97a2cbca67/bin) rather than the default fastbuild/bin. This caused three related issues — fixed here together.

Fix 1: Populate java_common.jars for java_proto_library from full_compile_jars (aspect)

java_proto_library targets have empty JavaInfo.java_outputs because the actual compilation (bazel_java_proto_aspect) runs in the transitioned config and its outputs are not surfaced through java_outputs. As a result, java_common.jars was always empty for these targets, and JavaLanguagePlugin created no library entries — so proto-generated Java classes never appeared in the IDE classpath.

Fix: In java_info.bzl.template, when jars is empty and the rule kind is java_proto_library, fall back to JavaInfo.full_compile_jars filtered to class jars owned by the current package only. The package filter is essential — full_compile_jars is transitive and without filtering every java_proto_library would register its entire transitive dependency tree, flooding the project model with hundreds of duplicate library entries.

if not jars and provider and ctx.rule.kind == "java_proto_library":
    full_compile = [
        f for f in getattr(provider, "full_compile_jars", depset()).to_list()
        if not f.basename.endswith("-hjar.jar") and f.owner.package == ctx.label.package
    ]

Fix 2: Prefer jar-bearing TargetInfo nodes in conflict resolution (TargetInfoReader)

When the BSP aspect runs alongside bazel_java_proto_aspect, both produce .bsp-info.textproto files for the same label — one in the default config (jar-less) and one in the transitioned config (contains the speed jars). The previous conflict resolution always picked the smallest-by-size node, which was the empty shell, leaving the library without any jars.

Fix: Among JVM nodes, prefer those with non-empty jarsList before falling back to smallest-by-size. The resolution logic is extracted into a testable companion object function with unit tests.

Fix 3: Place materialized jdeps sibling to source file (get_jdeps)

ctx.actions.declare_file("materialized_" + basename) places the output in the package root, causing action conflicts when two targets in the same BUILD package share a basename (e.g. TypesTest.jdeps). Adding sibling = raw_jdeps_file places each materialized file next to the source jdeps in the target's own subdirectory.

Fix 4: Retain original path for non-existent output files (DefaultBazelOutputFileHardLinks)

The ?: continue that silently dropped files that don't exist on disk was changed to retain the original path, so the library entry stays registered even if the jar hasn't been downloaded. IntelliJ's VFS surfaces access errors rather than silently losing the jar from the classpath.

Test plan

• Run TargetInfoReaderTest — covers all conflict-resolution branches including the proto shadow-graph case
• Sync a Bazel project containing java_proto_library deps and verify generated Java classes (e.g. Account.Builder) appear in autocomplete
• Verify no duplicate library entries for proto targets (project model size unchanged or reduced)
• Verify two java_test targets with the same basename in a single BUILD package build without action conflicts

🤖 Generated with Claude Code

[tboernerapex]

This improves code completion somewhat (basically never showing before) but I still have to type 5-6 characters before I get a suggestion.

[tboernerapex]

Still working on more fixes.

[tboernerapex]

Well at this point i'm not sure what else to try. Some of the early changes on this PR did help the indexing but the last few commits seem to have done nothing. I was asked to repro in https://youtrack.jetbrains.com/issue/BAZEL-3169 but the example project isn't working (see the comments). With the first few changes in this PR I am now able to do fuzzy searching on the protobuf fields but nothing appears initially after you add a . after the variable name.

[tboernerapex]

Ctrl+Space shows autocomplete just fine so the only issue is that it doesn't autocomplete after just a .

[tboernerapex]

Unable to reproduce the issue.