Don't register sources to kotlin srcDirs for android compilation

(cherry picked from commit 4c52e44)

Author: hfmehmed

gradle-plugin/src/main/kotlin/com/google/devtools/ksp/gradle/KspSubplugin.kt

@@ -20,7 +20,9 @@ import com.android.build.api.variant.Component
 import com.google.devtools.ksp.KspExperimental
 import com.google.devtools.ksp.gradle.model.builder.KspModelBuilder
 import com.google.devtools.ksp.gradle.utils.canUseGeneratedKotlinApi
+import com.google.devtools.ksp.gradle.utils.canUseInternalKspApis
 import com.google.devtools.ksp.gradle.utils.enableProjectIsolationCompatibleCodepath
+import com.google.devtools.ksp.gradle.utils.isAgpBuiltInKotlinUsed
 import com.google.devtools.ksp.gradle.utils.useLegacyVariantApi
 import org.gradle.api.Project
 import org.gradle.api.Task
@@ -207,15 +209,11 @@ class KspGradleSubplugin @Inject internal constructor(private val registry: Tool
             // They will be observed by downstreams and violate current build scheme.
             kotlinCompileProvider.configure { it.source(*generatedSources) }
         } else {
-            if (project.canUseGeneratedKotlinApi() && project.enableProjectIsolationCompatibleCodepath()) {
-                kotlinCompilation.defaultSourceSet.generatedKotlin.srcDir(
-                    kspTaskProvider.map { task -> task.kspConfig.kotlinOutputDir }
-                )
-                kotlinCompilation.defaultSourceSet.generatedKotlin.srcDir(
-                    kspTaskProvider.map { task -> task.kspConfig.javaOutputDir }
-                )
-            } else {
-                kotlinCompilation.defaultSourceSet.kotlin.srcDirs(*generatedSources)
+            val skipAddingSources = kotlinCompilation is KotlinJvmAndroidCompilation &&
+                project.isAgpBuiltInKotlinUsed() && project.canUseInternalKspApis()
+
+            if (!skipAddingSources) {
+                registerOutputWithKotlinSrcdirs(project, kotlinCompilation, kspTaskProvider, *generatedSources)
             }
         }
 
@@ -256,6 +254,25 @@ class KspGradleSubplugin @Inject internal constructor(private val registry: Tool
         return project.provider { emptyList() }
     }
 
+    private fun registerOutputWithKotlinSrcdirs(
+        project: Project,
+        kotlinCompilation: KotlinCompilation<*>,
+        kspTaskProvider: TaskProvider<KspAATask>,
+        vararg generatedSources: FileCollection
+    ) {
+        if (project.canUseGeneratedKotlinApi() && project.enableProjectIsolationCompatibleCodepath()) {
+            kotlinCompilation.defaultSourceSet.generatedKotlin.srcDir(
+                kspTaskProvider.map { task -> task.kspConfig.kotlinOutputDir }
+            )
+            kotlinCompilation.defaultSourceSet.generatedKotlin.srcDir(
+                kspTaskProvider.map { task -> task.kspConfig.javaOutputDir }
+            )
+        } else {
+            @Suppress("DEPRECATION")
+            kotlinCompilation.defaultSourceSet.kotlin.srcDirs(*generatedSources)
+        }
+    }
+
     override fun getCompilerPluginId() = KSP_PLUGIN_ID
     override fun getPluginArtifact(): SubpluginArtifact =
         SubpluginArtifact(

integration-tests/src/test/kotlin/com/google/devtools/ksp/test/AGPVersionIT.kt

@@ -38,6 +38,8 @@ class AGPVersionIT(
                 arrayOf("8.12.0-alpha06", "2.3.0-RC", "8.13"),
                 arrayOf("9.0.0-alpha12", "2.2.10", "9.1.0"),
                 arrayOf("9.0.0-alpha12", "2.3.0-RC", "9.1.0"),
+                arrayOf("9.0.0-alpha14", "2.2.10", "9.1.0"),
+                arrayOf("9.0.0-alpha14", "2.3.0-RC", "9.1.0"),
 
                 // AGP 8.7.0
                 arrayOf("8.7.0", "2.3.0-RC", "8.11.1"),