Add KSP Plugin Support #162

minkuan88 · 2026-01-06T16:54:38Z

Summary

Add KSP (Kotlin Symbol Processing) support to Grazel.

What's New

Auto-detect processor classes from JAR metadata
Generate kt_ksp_plugin rules in root BUILD.bazel
Emit plugins attribute on android_library, android_binary, and kotlin_library targets
Separate ksp_maven repository for processor dependencies
Configuration cache compatible

Test Plan

Added Moshi KSP testing to sample-android, sample-android-library, and sample-kotlin-library

- Add KspExtension DSL with nested compiler and processor configuration - Support version catalog references for processor configuration - Auto-detect processor_class from JAR's META-INF/services file - Configure generates_java and target_embedded_compiler per processor - Generate kt_ksp_plugin rules in root BUILD.bazel with all attributes - Add KspProcessorClassExtractor for reading processor classes from JARs - Fix Groovy closure delegation for nested DSL blocks - Add kspConfiguration support to Variant interface for extracting KSP deps - Emit plugins attribute on android_library/android_binary targets

@maven

- Add KSP scope to ResolveDependenciesResult for separate dependency tracking - Resolve KSP configurations (*KotlinProcessorClasspath) in ResolveVariantDependenciesTask - Aggregate KSP deps across all variants into single kspResult in ComputeWorkspaceDependencies - Generate ksp_maven maven_install from aggregated KSP dependencies - Add calculateRepositoriesIncludingTransitives to extract repos from transitive deps - Update KspRules to reference @ksp_maven instead of @maven for processor deps - Only include direct KSP processors in artifacts, let Bazel resolve transitives

Move KSP-related code out of GradleProjectInfo to ensure the implementation is configuration cache compatible. KSP processors are now built directly from WorkspaceDependencies in RootBazelFileBuilder. Changes: - Move KspProcessor data class to KspRules.kt - Remove hasKsp and kspDependencies from GradleProjectInfo interface - Add buildKspProcessors() method in RootBazelFileBuilder - Add collectKspPluginDeps() to DependenciesDataSource for module-level KSP deps - Update GenerateRootBazelScriptsTask to pass workspaceDependencies

- Moshi is simpler than Room (just @JsonClass annotation) - Added MoshiModel.kt with User data class for KSP generation - Added verifyKspCodeGeneration() in MainActivity to verify KSP-generated UserJsonAdapter works at compile time - Updated ksp_maven to use moshi-kotlin-codegen processor - Verified both Gradle and Bazel builds pass

Similar to PR grab#159, this optimizes configuration time by skipping expensive KSP resolution for projects/variants without KSP deps. - Add hasKspDependencies() to check project's base ksp configuration - Conditionally process KSP configs only when dependencies exist - Skip processor class extraction and resolution when not needed

Extend KSP support to pure Kotlin (JVM) library modules by wiring up the plugin extraction in KotlinProjectDataExtractor and passing plugins through to the generated kotlin_library targets. Changes: - Add plugins field to KotlinProjectData - Extract KSP plugins via collectKspPluginDeps() in extractor - Pass plugins to KotlinLibraryTarget in builder Also add KSP/Moshi testing to sample modules: - sample-kotlin-library: Add KotlinConfig data class with @JsonClass - sample-android-library: Add @JsonClass to User (alongside @parcelize)

arunsampathkumar-grabtaxi · 2026-01-12T02:54:06Z

...ugin/src/main/kotlin/com/grab/grazel/migrate/dependencies/MavenInstallArtifactsCalculator.kt

+        // Format: "group:name:version:repository:requiresJetifier:jetifierSource"
+        artifacts.flatMap { it.dependencies }
+            .mapNotNull { depNotation ->
+                val parts = depNotation.split(":")


Lets unify this parsing under https://github.com/grab/grazel/blob/master/grazel-gradle-plugin/src/main/kotlin/com/grab/grazel/gradle/dependencies/model/ResolveDependenciesResult.kt#L76 in one place. These is a chance this may drift and hard to catch later on

888dd6c addresses this

arunsampathkumar-grabtaxi · 2026-01-12T02:55:48Z

grazel-gradle-plugin/src/main/kotlin/com/grab/grazel/extension/KotlinExtension.kt

+     * @param coordinate Maven coordinate in format "group:artifact"
+     */
+    fun processor(coordinate: String, block: KspProcessorConfig.() -> Unit) {
+        processors.getOrPut(coordinate) { KspProcessorConfig() }.apply(block)


Add a validation for the coordinate so that unexpected input don't crash the parsing later on

b662d48 addresses this

arunsampathkumar-grabtaxi · 2026-01-12T02:58:18Z

...adle-plugin/src/main/kotlin/com/grab/grazel/tasks/internal/ResolveVariantDependenciesTask.kt

+            val hasKsp = hasKspDependencies(variant, project)
+
+            // Collect KSP direct dependencies only if variant has KSP deps
+            val directDependenciesKsp: org.gradle.api.provider.Provider<Map<String, String>>


Consider fixing imports

888dd6c addresses this

arunsampathkumar-grabtaxi · 2026-01-12T02:58:45Z

...adle-plugin/src/main/kotlin/com/grab/grazel/tasks/internal/ResolveVariantDependenciesTask.kt

            }

+            // Check if variant has KSP dependencies before processing
+            val hasKsp = hasKspDependencies(variant, project)


Probably worth moving all ksp related to new function

b662d48 addresses this

arunsampathkumar-grabtaxi · 2026-01-12T03:00:40Z

...adle-plugin/src/main/kotlin/com/grab/grazel/tasks/internal/ResolveVariantDependenciesTask.kt

+                processorClasses = kspConfigurationProvider.map { configs ->
+                    configs
+                        .filter { it.isCanBeResolved }
+                        .flatMap { KspProcessorClassExtractor.extractProcessorClasses(it).entries }


All this is quite heavy to run in configuration phase (although this happens inside a provider) , the classes can be computed as part of task itself and just declare the configurations as input to the task.

will address this in a separate PR

arunsampathkumar-grabtaxi · 2026-01-12T03:01:21Z

...adle-plugin/src/main/kotlin/com/grab/grazel/tasks/internal/ResolveVariantDependenciesTask.kt

+
+            // Check if project has any KSP dependencies declared
+            // The 'ksp' configuration is the base config that variant-specific configs extend from
+            val kspConfig = project.configurations.findByName("ksp")


This will force resolve the configuration and bad for performance, we are computing it already in grazelVariant.kspConfiguration, can use that directly.

will address this is a separate PR

arunsampathkumar-grabtaxi · 2026-01-12T03:01:58Z

sample-android/src/main/java/com/grab/grazel/android/sample/MoshiModel.kt

@@ -0,0 +1,29 @@
+/*
+ * Copyright 2022 Grabtaxi Holdings PTE LTD (GRAB)


Lets update this for new code.

888dd6c addresses this

Use ResolvedDependency::from to centralize coordinate parsing instead of manually splitting notation strings. Also fix copyright year.

- Add validateCoordinate() for processor coordinate input - Extract KSP logic into collectKspDependencyInfo() function - Add KspDependencyInfo data class to encapsulate KSP state - Clean up imports in ResolveVariantDependenciesTask

minkuan88 requested review from adarsh-grabtaxi, arnav-grabtaxi, arunsampathkumar-grabtaxi, minkuanlim-grabtaxi and vanminh-grabtaxi as code owners January 6, 2026 16:54

arunsampathkumar-grabtaxi force-pushed the ksp-support-modules branch from 60ab07a to df25ba1 Compare January 7, 2026 04:00

minkuan88 force-pushed the ksp-support-modules branch from df25ba1 to 2797a31 Compare January 8, 2026 18:20

minkuan88 changed the title ~~Add complete KSP plugin support with auto-detection and configuration~~ Add KSP Plugin Support Jan 8, 2026

minkuan88 added 2 commits January 9, 2026 13:24

minkuan88 force-pushed the ksp-support-modules branch from 2797a31 to 94cadce Compare January 9, 2026 05:34

minkuan88 force-pushed the ksp-support-modules branch from 94cadce to da72ecb Compare January 9, 2026 05:39

minkuan88 added 3 commits January 9, 2026 16:11

minkuan88 force-pushed the ksp-support-modules branch from 30beffa to 4d1d730 Compare January 10, 2026 04:11

arunsampathkumar-grabtaxi reviewed Jan 12, 2026

View reviewed changes

minkuan88 added 2 commits January 12, 2026 16:21

Unify transitive dependency parsing in MavenInstallArtifactsCalculator

888dd6c

Use ResolvedDependency::from to centralize coordinate parsing instead of manually splitting notation strings. Also fix copyright year.

Refactor KSP handling and add coordinate validation

b662d48

- Add validateCoordinate() for processor coordinate input - Extract KSP logic into collectKspDependencyInfo() function - Add KspDependencyInfo data class to encapsulate KSP state - Clean up imports in ResolveVariantDependenciesTask

minkuan88 requested a review from arunsampathkumar-grabtaxi January 12, 2026 09:10

arunsampathkumar-grabtaxi approved these changes Jan 13, 2026

View reviewed changes

minkuanlim-grabtaxi merged commit 92f9634 into grab:master Jan 13, 2026
8 checks passed

minkuan88 mentioned this pull request Jan 13, 2026

Optimize KSP resolution #165

Merged

		@@ -0,0 +1,29 @@
		/*
		* Copyright 2022 Grabtaxi Holdings PTE LTD (GRAB)

Add KSP Plugin Support #162

Add KSP Plugin Support #162

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minkuan88 commented Jan 6, 2026 • edited by minkuanlim-grabtaxi Loading Uh oh! There was an error while loading. Please reload this page.

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arunsampathkumar-grabtaxi Jan 12, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

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arunsampathkumar-grabtaxi Jan 12, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

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minkuan88 commented Jan 6, 2026 •

edited by minkuanlim-grabtaxi

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arunsampathkumar-grabtaxi Jan 12, 2026 •

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