Bazel compilation changes for unused dependencies checking by JonathanPerry651 · Pull Request #30808 · bazelbuild/bazel

JonathanPerry651 · 2026-08-20T09:15:00Z

This pull request contains the Bazel-side changes for unused dependencies checking, splitting the functionality as requested by @hvadehra in #29770. This PR requires the JavaBuilder-side changes from #30807.

bazel-docs-pr-commenter · 2026-08-20T09:46:43Z

✅ Bazel docs preview is ready!

Preview URL: https://bazel-pr-30808.mintlify.app/

Updated for 487d3eb8d7d87662069c2b5c609c6878e280be9a

hvadehra · 2026-08-25T09:14:23Z

Please rebase after 61218bb

Also, why does this not match the latest state of #29770 ?

JonathanPerry651 · 2026-08-25T09:20:40Z

Please rebase after 61218bb

On it.

Also, why does this not match the latest state of #29770 ?

Yeah I was about to post on that - I took the PRs and actually tried them out against my repo, and discovered that the code that i thought was testing the behaviour in fact was not, since it was short-circuiting when it discovered that the functionality wasn't supported! So I fixed the tests to not short circuit, and then fixed the code to...actually work.

Very sorry for the weirdness!

JonathanPerry651 · 2026-08-25T12:03:53Z

@hvadehra - rebase is done, everything looks clean

hvadehra · 2026-08-25T12:35:41Z

What about the discussion under #29770 (comment) where we decided to make Bazel unaware of any of these changes and just pass through the args (as you implemented in d1c7648)?

JonathanPerry651 · 2026-08-25T12:51:50Z

I am so sorry, I got in a git tangle. Let me fix and get back to you.

JonathanPerry651 · 2026-08-25T13:37:34Z

@hvadehra - OK I unborked myself, sorry again for my silliness.

There's code in the tests which shortcuts the new functionality if the referenced rules_java doesn't contain its side of the code, or else (for the internal test) shortcuts if the packaged JavaBuilder is the 'released' version. I don't feel super comfortable that I've gotten that right, especially given that I got it wrong before (which is why the code I had previously was totally borked :( )

hvadehra · 2026-08-26T09:54:26Z

+    for (CommandLine extraCommandLine : extraCommandLineArgs) {
+      commandLinesBuilder.addCommandLine(extraCommandLine, PARAM_FILE_INFO);
+    }
+    commandLinesBuilder.addCommandLine(classpathLine.build(), PARAM_FILE_INFO);


Is it important that the classpath line is added last?

No good reason; cleaned up and moved extraCommandLineArgs to the end.

hvadehra · 2026-08-26T09:56:49Z

+      name = "is_unused_deps_supported",
+      documented = false,
+      useStarlarkThread = true)
+  default boolean isUnusedDepsSupported(StarlarkThread thread) throws EvalException {


We don't need this API, we can derive this from the Bazel version.

Good point — removed is_unused_deps_supported from JavaCommonApi, JavaStarlarkCommon, and java_common.bzl.

hvadehra · 2026-08-26T10:02:08Z

+            ? ImmutableList.of()
+            : Sequence.cast(extraArgs, CommandLineArgsApi.class, "extra_args");
+    ImmutableList.Builder<CommandLine> extraCommandLineArgs = ImmutableList.builder();
+    ImmutableSet.Builder<Artifact> extraDirectoryInputs = ImmutableSet.builder();


Why do we need this special handling of extraDirectoryInputs?

Removed extraDirectoryInputs. Since create_compilation_action already provides an additional_inputs parameter for any input artifacts, extra_args only needs to forward the CommandLine objects.

hvadehra · 2026-08-26T10:46:30Z

            .manifestProto(manifestProto)
            .build();
+    Iterable<CommandLineArgsApi> extraArgsList =
+        (extraArgs == null || extraArgs == Starlark.NONE)


This could be simpler if we make the default value [].

hvadehra · 2026-08-26T10:47:12Z

+    Iterable<CommandLineArgsApi> extraArgsList =
+        (extraArgs == null || extraArgs == Starlark.NONE)
+            ? ImmutableList.of()
+            : Sequence.cast(extraArgs, CommandLineArgsApi.class, "extra_args");


Lets just Sequence.cast() to Args.class and simplify?

hvadehra · 2026-08-26T10:47:37Z

    }

+    @CanIgnoreReturnValue
+    public Builder addAdditionalInputs(Iterable<Artifact> additionalInputs) {


removed thanks

hvadehra · 2026-08-26T11:30:18Z

            .addSourceJars(Sequence.cast(sourceJars, Artifact.class, "source_jars"))
            .addSourceFiles(Depset.noneableCast(sourceFiles, Artifact.class, "sources").toList())
            .addDirectJars(directJars.getSet(Artifact.class))
+            .addExtraCommandLineArgs(extraCommandLineArgs.build())


Passing this indirectly via JavaTargetsAttributes seems unnecessary. Should we just add it to JavaCompilationHelper instead?

Good idea, moved extraCommandLineArgs directly to JavaCompilationHelper and removed it from JavaTargetAttributes.

hvadehra · 2026-08-26T11:32:15Z

  }
+
+  @Test
+  public void testUnusedDepsVerifyFlags() throws Exception {


from Bazel's perspective, we're just passing through any extra Args supplied from Starlark. Lets rename + simplify the test to just ensure any extra --foo=bar type arguments get propagated.

Simplified and renamed test to check --foo=bar propagation.

hvadehra · 2026-08-26T11:34:51Z

+  }
+
+  @Test
+  public void testExtraArgs_invalidElementTypeThrows() throws Exception {


unnecessary - this is exercising Bazel's Starlark builtin machinery, it has nothing to do with java compilation.

JonathanPerry651 · 2026-09-02T14:59:25Z

@bazel-io flag

Please consider cherry-picking this change into Bazel 9.3.0.

fmeum · 2026-09-02T16:00:13Z

@bazel-io fork 9.3.0

fmeum · 2026-09-02T16:00:39Z

@iancha1992 Could you mark this for an 8.9.0 release if we ever have one? This would make it easier to support new rules_java features with old versions of Bazel.

…compilation_action` (bazelbuild#30808) This allows faster iteration on the `rules_java` <> `JavaBuilder` contract without having to wait for Bazel changes/releases. In the immediate future, this will be used for the unused-deps checking. Longer term this should also help in migrating off the native compilation code. Note: the added integration shell test is currently a no-op on CI (since we need the corresponding rules_java changes) but does allow for local testing with an overridden `@rules_java`. Closes bazelbuild#30808. PiperOrigin-RevId: 971826913 Change-Id: I8047e057716475a7a4d8bff48b8c7bfe6d79ba1c (cherry picked from commit 0e6f09d)

….create_compilation_action` (bazelbuild#30981) This allows faster iteration on the `rules_java` <> `JavaBuilder` contract without having to wait for Bazel changes/releases. In the immediate future, this will be used for the unused-deps checking. Longer term this should also help in migrating off the native compilation code. Note: the added integration shell test is currently a no-op on CI (since we need the corresponding rules_java changes) but does allow for local testing with an overridden `@rules_java`. Closes bazelbuild#30808. PiperOrigin-RevId: 971826913 Change-Id: I8047e057716475a7a4d8bff48b8c7bfe6d79ba1c (cherry picked from commit 0e6f09d) 9.3.0 adaptation: `java_common.bzl` has no `_ALLOWLIST` constant on this branch, so `bazel_internal/test_rules` is added to the allowlist passed inline to `check_private_api`. `JavaCompileActionBuilderTest` needed a `testutil:TestConstants` dep for the new test. The `bazel_java_test.sh` cases are left out: they exercise `--experimental_check_unused_deps`, which is a JavaBuilder option added by bazelbuild#30807 and not present on this branch, and they are a no-op on CI anyway. `JavaCompileActionBuilderTest` and all four shards of `//src/test/shell/bazel:bazel_java_test_jdk17_toolchain_head` pass locally. Closes bazelbuild#30968 Co-authored-by: Jonathan Perry <jonathan.perry@gs.com>

JonathanPerry651 requested review from a team and lberki as code owners August 20, 2026 09:15

JonathanPerry651 requested review from aranguyen and removed request for a team August 20, 2026 09:15

JonathanPerry651 mentioned this pull request Aug 20, 2026

Add support for detection of unused java dependencies #29770

Closed

2 tasks

JonathanPerry651 force-pushed the unused-deps-bazel branch from e3cc12d to f80f73a Compare August 20, 2026 09:21

JonathanPerry651 requested a review from a team as a code owner August 20, 2026 09:21

bazel-docs-pull-requestor Bot mentioned this pull request Aug 20, 2026

docs preview: bazelbuild/bazel#30808 bazel-contrib/bazel-docs#676

Closed

hvadehra removed team-Configurability platforms, toolchains, cquery, select(), config transitions team-Rules-API API for writing rules/aspects: providers, runfiles, actions, artifacts labels Aug 21, 2026

hvadehra requested review from hvadehra and removed request for aranguyen and lberki August 21, 2026 08:14

JonathanPerry651 mentioned this pull request Aug 24, 2026

JavaBuilder changes for unused dependencies checking #30807

Closed

JonathanPerry651 force-pushed the unused-deps-bazel branch from f80f73a to 9f28a7a Compare August 25, 2026 11:34

JonathanPerry651 force-pushed the unused-deps-bazel branch from 9f28a7a to c1dc2fa Compare August 25, 2026 13:17

hvadehra requested changes Aug 26, 2026

View reviewed changes

JonathanPerry651 force-pushed the unused-deps-bazel branch from c1dc2fa to b47e482 Compare August 26, 2026 10:31

hvadehra requested changes Aug 26, 2026

View reviewed changes

JonathanPerry651 force-pushed the unused-deps-bazel branch from b47e482 to b50472b Compare August 26, 2026 11:10

hvadehra requested changes Aug 26, 2026

View reviewed changes

JonathanPerry651 added 2 commits August 26, 2026 12:53

Support extra_args in java_common.create_compilation_action

5807225

Add conditional end-to-end integration test for unused deps

487d3eb

JonathanPerry651 force-pushed the unused-deps-bazel branch from b50472b to 487d3eb Compare August 26, 2026 11:54

hvadehra approved these changes Aug 26, 2026

View reviewed changes

copybara-service Bot closed this in 0e6f09d Aug 27, 2026

github-actions Bot removed the awaiting-review PR is awaiting review from an assigned reviewer label Aug 27, 2026

bazel-io mentioned this pull request Sep 2, 2026

[9.3.0] Bazel compilation changes for unused dependencies checking #30968

Closed

fmeum mentioned this pull request Sep 2, 2026

[9.3.0] Support pass-through Args for JavaBuilder in java_common.create_compilation_action #30981

Merged

iancha1992 added the potential release blocker Flagged by community members using "@bazel-io flag". Should be added to a release blocker milestone label Sep 2, 2026

Uh oh!

Conversation

JonathanPerry651 commented Aug 20, 2026

Uh oh!

bazel-docs-pr-commenter Bot commented Aug 20, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Uh oh!

hvadehra commented Aug 25, 2026

Uh oh!

JonathanPerry651 commented Aug 25, 2026

Uh oh!

JonathanPerry651 commented Aug 25, 2026

Uh oh!

hvadehra commented Aug 25, 2026

Uh oh!

JonathanPerry651 commented Aug 25, 2026

Uh oh!

JonathanPerry651 commented Aug 25, 2026

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

JonathanPerry651 commented Sep 2, 2026

Uh oh!

fmeum commented Sep 2, 2026

Uh oh!

fmeum commented Sep 2, 2026

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

4 participants

bazel-docs-pr-commenter Bot commented Aug 20, 2026 •

edited

Loading