KT-45777: Support compile avoidance

Test: Updated existing incremental compilation integration tests

libraries/tools/kotlin-gradle-plugin-integration-tests/src/test/kotlin/org/jetbrains/kotlin/gradle/IncrementalCompilationMultiProjectIT.kt

@@ -159,7 +159,7 @@ class IncrementalCompilationClasspathSnapshotJvmMultiProjectIT : IncrementalComp
             modifyProject = changeMethodBodyInLib,
             assertResults = {
                 assertTasksExecuted(":lib:$compileKotlinTaskName")
-                assertTasksExecuted(":app:$compileKotlinTaskName") // TODO: App compilation should have 'compile avoidance'
+                assertTasksUpToDate(":app:$compileKotlinTaskName") // App compilation has 'compile avoidance'
                 assertCompiledKotlinFiles(File(project.projectDir, "lib").getFilesByNames("A.kt"))
             }
         )
@@ -198,7 +198,7 @@ class IncrementalCompilationClasspathSnapshotJvmMultiProjectIT : IncrementalComp
     override fun testCompileLibWithGroovy() {
         testCompileLibWithGroovy_doTest {
             assertTasksExecuted(":lib:$compileKotlinTaskName")
-            assertTasksExecuted(":app:$compileKotlinTaskName") // TODO: App compilation should have 'compile avoidance'
+            assertTasksUpToDate(":app:$compileKotlinTaskName") // App compilation has 'compile avoidance'
             assertCompiledKotlinFiles(listOf(File(project.projectDir, "lib").getFileByName("A.kt")))
         }
     }

libraries/tools/kotlin-gradle-plugin-integration-tests/src/test/kotlin/org/jetbrains/kotlin/gradle/IncrementalJavaChangeIT.kt

@@ -50,7 +50,7 @@ class IncrementalJavaChangeClasspathSnapshotIT : IncrementalJavaChangeDefaultIT(
             javaClassInLib, changeMethodBody,
             assertResults = {
                 assertTasksExecuted(":lib:compileKotlin")
-                assertTasksExecuted(":app:compileKotlin") // TODO: App compilation should have 'compile avoidance'
+                assertTasksUpToDate(":app:compileKotlin") // App compilation has 'compile avoidance'
                 assertCompiledKotlinFiles(emptyList())
             }
         )

libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/tasks/Tasks.kt

@@ -547,6 +547,8 @@ abstract class KotlinCompile @Inject constructor(
                 val classpathSnapshotDir = getClasspathSnapshotDir(task)
                 task.classpathSnapshotProperties.classpathSnapshotDir.value(classpathSnapshotDir).disallowChanges()
                 task.classpathSnapshotProperties.classpathSnapshotDirFileCollection.from(classpathSnapshotDir)
+            } else {
+                task.classpathSnapshotProperties.classpath.from(task.project.provider { task.classpath })
             }
         }
     }
@@ -578,6 +580,11 @@ abstract class KotlinCompile @Inject constructor(
             logger.kotlinDebug { "Set $this.usePreciseJavaTracking=$value" }
         }
 
+    @Internal // To support compile avoidance (ClasspathSnapshotProperties.classpathSnapshot will be used as input instead)
+    override fun getClasspath(): FileCollection {
+        return super.getClasspath()
+    }
+
     @get:Nested
     abstract val classpathSnapshotProperties: ClasspathSnapshotProperties
 
@@ -591,6 +598,11 @@ abstract class KotlinCompile @Inject constructor(
         @get:Optional // Set if useClasspathSnapshot == true
         abstract val classpathSnapshot: ConfigurableFileCollection
 
+        @get:Classpath
+        @get:Incremental
+        @get:Optional // Set if useClasspathSnapshot == false (to restore the existing classpath annotations when the feature is disabled)
+        abstract val classpath: ConfigurableFileCollection
+
         @get:OutputDirectory
         @get:Optional // Set if useClasspathSnapshot == true
         abstract val classpathSnapshotDir: DirectoryProperty
@@ -663,7 +675,7 @@ abstract class KotlinCompile @Inject constructor(
     }
 
     override val incrementalProps: List<FileCollection>
-        get() = super.incrementalProps + listOf(classpathSnapshotProperties.classpathSnapshot)
+        get() = listOf(stableSources, commonSourceSet, classpathSnapshotProperties.classpath, classpathSnapshotProperties.classpathSnapshot)
 
     override fun getSourceRoots(): SourceRoots.ForJvm = jvmSourceRoots