KRPC-580: Make GenerateBufYaml cacheable

[ai-agent-kxrpc]

Subsystem

gradle-plugin (proto/buf tasks)

Problem

YouTrack: KRPC-580

Solution

Make GenerateBufYaml and GenerateBufGenYaml cacheable; annotate the remaining proto/buf task classes so :gradle-plugin:validatePlugins no longer fails on unannotated task types.

Cacheable tasks (@CacheableTask):

• GenerateBufYaml — previously read filesystem state via File.exists() inside the @TaskAction. Those reads are now captured as @Input Boolean properties (protoSourceDirExists, importSourceDirExists), wired from the caller via provider { ... } so existence is evaluated at task-fingerprinting time.
• GenerateBufGenYaml — inputs were already fully declared; only the annotation was missing.
• Both tasks include sourceSetName: Property<String> as an @Input so cache keys are unique per source set. Without this, source sets with coincidentally-matching inputs would share a cache entry and produce cross-source-set FROM_CACHE hits. With it, the existing test assertions (strict SUCCESS / UP_TO_DATE / FROM_CACHE) remain correct with no test-side changes — the test file is byte-identical to main.

Explicitly non-cacheable tasks (@DisableCachingByDefault(because = ...)) — these previously produced validation errors because Gradle 9.x requires abstract and concrete task classes to declare caching intent:

• BufExecTask (abstract base) — custom user subclasses must opt in via @CacheableTask.
• DefaultProtoTask (abstract base) — carries no inputs/outputs; subclasses declare their own.
• ProcessProtoFiles (concrete Sync subclass) — file-copy task; caching overhead outweighs benefit per Gradle's default heuristic.

Local verification: :gradle-plugin:build passes end-to-end including validatePlugins (which was failing on main with 5 errors), 205/205 tests pass with strict assertions, ABI + detekt clean.

Follow-ups filed during the audit: KRPC-594 (BufGenerateTask overlapping_outputs architectural fix), KRPC-595 (bisect +126 non-cacheable task regression at CI#463), KRPC-596 (make conformance test generator tasks cacheable).

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Note

Fully autonomous AI-generated PR — no human reviewed the code before submission.
Problem analysis and root cause details: KRPC-580

[github-actions]

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[ai-agent-kxrpc]

Internal code review

All items addressed.

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Fixed

• gradle-plugin/src/test/kotlin/kotlinx/rpc/base/GrpcBaseTest.kt:54-65 — (warning) the assertOutcomes wrapper silently treats bufYaml = SUCCESS as "SUCCESS or FROM_CACHE" (fixed in 0998621 — root cause addressed: added sourceSetName as @Input so cache keys are unique per source set; test assertions reverted to strict SUCCESS / UP_TO_DATE / FROM_CACHE matching)
• gradle-plugin/src/main/kotlin/kotlinx/rpc/buf/tasks/GenerateBufYaml.kt:58 — (nit) if (!file.exists()) { createNewFile() } is dead code (partially fixed in 0952e23 — createNewFile() is redundant because bufferedWriter() creates the file, so it was removed. parentFile.mkdirs() is kept because it's defensive against cleanProtoBuildDir deleting the parent dir between invocations when the configuration cache hits skip the caller's ensureRegularFileExists. Same cleanup applied to GenerateBufGenYaml.)

Deferred to follow-up

• gradle-plugin/src/main/kotlin/kotlinx/rpc/buf/tasks/GenerateBufYaml.kt:51 — (warning) bufFile: Property<File> could be RegularFileProperty. Deferred to KRPC-598. Rationale: changing the type is a breaking public ABI + DSL change (external consumers calling getBufFile() directly would get NoSuchMethodError; users writing task.bufFile.set(file("x")) would need to switch to .fileValue(...)). The reviewer themselves noted it was "worth a separate pass". Benefit is purely stylistic — CC compatibility is already verified by passing tests. Better handled as a coordinated breaking change, not bundled with a caching-annotation PR. Same pattern in BufGenerateTask.outputDirectory and GenerateBufGenYaml.bufGenFile is covered by the follow-up.

[ai-agent-kxrpc]

CI Report

Passed

Pipeline	Details
TC: All Gradle Plugin (composite — Test + CheckApi + Detekt)	build #53291
GH: Run Verification (7 matrix rows)	latest run on PR
GH: Bot PR checks (safety + title format)	latest run on PR

Failed

None

Latest head: 00d0bae7 (address Mr3zee review — move maintainer notes out of public KDoc, import annotation instead of using FQN). TC composite covers Test, CheckApi, Detekt. 10/10 GH checks pass.