feat(kotlin): extend abi compile-avoidance to mixed kotlin+java targets

[Alan Wisper (wisper-dev)]

Do not merge until an Elide release containing elide-dev/WHIPLASH#1157
(mixed --abi-only) is published. Until then //e2e/abi_avoidance is red in
CI: the release pinned in versions.bzl cannot yet emit Java ABI for mixed
targets. After the release, bump versions.bzl to it (+ sha256 for all four
platforms) and CI goes green.

Why

After elide-dev/WHIPLASH#1157, elide kotlinc --abi-only emits both the Kotlin
and Java ABI, not just Kotlin. ABI compile-avoidance can therefore extend from
kt-only to mixed kt+java targets, which previously fell back to the
body-sensitive run_ijar jar and got no pruning.

What changes

• elide/private/compile_common.bzl: drop the and not has_java gate — with
  --//config/kotlinc:abi_compile_avoidance on, mixed targets also emit the
  --abi-only header action and use it as JavaInfo.compile_jar.
• tests/kotlin_rule_test.bzl: _abi_avoidance_mixed_fallback_test is renamed to
  _abi_avoidance_mixed_test and flipped — it now asserts exactly one
  --abi-only action and an _abi.jar compile_jar.
• e2e/abi_avoidance/run.sh: the mixed assertion now expects both the Kotlin and
  Java ABI.

Still opt-in via --//config/kotlinc:abi_compile_avoidance; no change without it.

Testing (locally, against a build with the WHIPLASH#1157 capability)

• Bazel analysis: the full //tests:kotlin_rule_tests suite passes 12/12
  (including the flipped mixed test and the unchanged kt-only test).
• e2e run.sh against a binary with the capability: all assertions pass
  (prune-soundness: body -> same, const/inline/signature -> diff; and
  mixed-kt-and-java).

Before merge

Bump versions.bzl to a release that includes elide-dev/WHIPLASH#1157.

[Copilot]

Pull request overview

This PR extends Bazel/Kotlin ABI compile-avoidance to mixed Kotlin+Java targets by enabling the elide kotlinc --abi-only header path for those targets, and updates analysis + e2e tests to assert the new mixed-target behavior.

Changes:

• Enable ABI compile-avoidance for any target with Kotlin sources (including mixed Kotlin+Java) in run_kotlinc.
• Update Kotlin rule analysis tests to expect an ElideKotlincAbi action and _abi.jar compile jar for mixed fixtures.
• Update the ABI-avoidance e2e harness expectations to require both Kotlin and Java ABI output for mixed compilation.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 1 comment.

File	Description
elide/private/compile_common.bzl	Expands the abi_avoidance gate to include mixed Kotlin+Java targets.
tests/kotlin_rule_test.bzl	Flips/renames the mixed ABI avoidance analysis test to expect --abi-only + _abi.jar for mixed targets.
e2e/abi_avoidance/run.sh	Updates the mixed-source e2e assertion to require both Kotlin and Java ABI output.

Comments suppressed due to low confidence (1)

elide/private/compile_common.bzl:300

• abi_avoidance now applies to mixed kt+java targets, but the ElideKotlincAbi action still only passes kt_srcs (and declares only kt_srcs as direct inputs). For mixed targets this will generate a Kotlin-only header and can drop Java ABI, which is exactly what the change is trying to avoid; it may also fail under sandboxing if .java files aren’t declared as inputs but are passed to the compiler.

To make mixed-mode avoidance correct, update the abi-only invocation to include java_srcs both in the argv and in the action inputs (e.g., abi_args.add_all(kt_srcs + java_srcs) and inputs.direct = kt_srcs + java_srcs).

    abi_avoidance = ctx.attr._abi_compile_avoidance[BuildSettingInfo].value and has_kt

    abi_jar = None
    if abi_avoidance:
        abi_jar = ctx.actions.declare_file(ctx.label.name + "_abi.jar")

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[codspeed-hq]

Merging this PR will not alter performance

⚠️ Unknown Walltime execution environment detected

Using the Walltime instrument on standard Hosted Runners will lead to inconsistent data.

For the most accurate results, we recommend using CodSpeed Macro Runners: bare-metal machines fine-tuned for performance measurement consistency.

✅ 9 untouched benchmarks

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_{Comparing feat/abi-avoidance-mixed-java (89654a5) with main (0972f13)}