Clean code-gen directory if there was deleted a dependency on the res library (#4257)

fixes https://github.com/JetBrains/compose-multiplatform/issues/4242

gradle-plugins/compose/src/main/kotlin/org/jetbrains/compose/resources/GenerateResClassTask.kt

@@ -12,10 +12,13 @@ import kotlin.io.path.relativeTo
 /**
  * This task should be FAST and SAFE! Because it is being run during IDE import.
  */
-abstract class GenerateResClassTask : DefaultTask() {
+internal abstract class GenerateResClassTask : DefaultTask() {
     @get:Input
     abstract val packageName: Property<String>
 
+    @get:Input
+    abstract val shouldGenerateResClass: Property<Boolean>
+
     @get:InputFiles
     @get:PathSensitive(PathSensitivity.RELATIVE)
     abstract val resDir: Property<File>
@@ -26,32 +29,37 @@ abstract class GenerateResClassTask : DefaultTask() {
     @TaskAction
     fun generate() {
         try {
-            val rootResDir = resDir.get()
-            logger.info("Generate resources for $rootResDir")
+            val kotlinDir = codeDir.get().asFile
+            logger.info("Clean directory $kotlinDir")
+            kotlinDir.deleteRecursively()
+            kotlinDir.mkdirs()
 
-            //get first level dirs
-            val dirs = rootResDir.listNotHiddenFiles()
+            if (shouldGenerateResClass.get()) {
+                val rootResDir = resDir.get()
+                logger.info("Generate resources for $rootResDir")
 
-            dirs.forEach { f ->
-                if (!f.isDirectory) {
-                    error("${f.name} is not directory! Raw files should be placed in '${rootResDir.name}/files' directory.")
-                }
-            }
+                //get first level dirs
+                val dirs = rootResDir.listNotHiddenFiles()
 
-            //type -> id -> resource item
-            val resources: Map<ResourceType, Map<String, List<ResourceItem>>> = dirs
-                .flatMap { dir ->
-                    dir.listNotHiddenFiles()
-                        .mapNotNull { it.fileToResourceItems(rootResDir.toPath()) }
-                        .flatten()
+                dirs.forEach { f ->
+                    if (!f.isDirectory) {
+                        error("${f.name} is not directory! Raw files should be placed in '${rootResDir.name}/files' directory.")
+                    }
                 }
-                .groupBy { it.type }
-                .mapValues { (_, items) -> items.groupBy { it.name } }
 
-            val kotlinDir = codeDir.get().asFile
-            kotlinDir.deleteRecursively()
-            kotlinDir.mkdirs()
-            getResFileSpec(resources, packageName.get()).writeTo(kotlinDir)
+                //type -> id -> resource item
+                val resources: Map<ResourceType, Map<String, List<ResourceItem>>> = dirs
+                    .flatMap { dir ->
+                        dir.listNotHiddenFiles()
+                            .mapNotNull { it.fileToResourceItems(rootResDir.toPath()) }
+                            .flatten()
+                    }
+                    .groupBy { it.type }
+                    .mapValues { (_, items) -> items.groupBy { it.name } }
+                getResFileSpec(resources, packageName.get()).writeTo(kotlinDir)
+            } else {
+                logger.info("Generation Res class is disabled")
+            }
         } catch (e: Exception) {
             //message must contain two ':' symbols to be parsed by IDE UI!
             logger.error("e: GenerateResClassTask was failed:", e)

gradle-plugins/compose/src/main/kotlin/org/jetbrains/compose/resources/ResourcesGenerator.kt

@@ -54,7 +54,7 @@ private fun Project.configureResourceGenerator(commonComposeResourcesDir: File,
     fun buildDir(path: String) = layout.dir(layout.buildDirectory.map { File(it.asFile, path) })
 
     //lazy check a dependency on the Resources library
-    val shouldGenerateResourceAccessors: Provider<Boolean> = provider {
+    val shouldGenerateResClass: Provider<Boolean> = provider {
         if (ComposeProperties.alwaysGenerateResourceAccessors(project).get()) {
             true
         } else {
@@ -72,9 +72,9 @@ private fun Project.configureResourceGenerator(commonComposeResourcesDir: File,
         GenerateResClassTask::class.java
     ) {
         it.packageName.set(packageName)
+        it.shouldGenerateResClass.set(shouldGenerateResClass)
         it.resDir.set(commonComposeResources)
         it.codeDir.set(buildDir("$RES_GEN_DIR/kotlin"))
-        it.onlyIf { shouldGenerateResourceAccessors.get() }
     }
 
     //register generated source set
@@ -93,7 +93,7 @@ private fun Project.configureResourceGenerator(commonComposeResourcesDir: File,
             configureAndroidResources(
                 commonComposeResources,
                 buildDir("$RES_GEN_DIR/androidFonts").map { it.asFile },
-                shouldGenerateResourceAccessors
+                shouldGenerateResClass
             )
         }
     }

gradle-plugins/compose/src/test/kotlin/org/jetbrains/compose/test/tests/integration/ResourcesTest.kt

@@ -117,6 +117,56 @@ class ResourcesTest : GradlePluginTestBase() {
         }
     }
 
+    @Test
+    fun testUpToDateChecks(): Unit = with(testProject("misc/commonResources")) {
+        gradle("prepareKotlinIdeaImport").checks {
+            check.taskSuccessful(":generateComposeResClass")
+            assert(file("build/generated/compose/resourceGenerator/kotlin/app/group/resources_test/generated/resources/Res.kt").exists())
+        }
+        gradle("prepareKotlinIdeaImport").checks {
+            check.taskUpToDate(":generateComposeResClass")
+        }
+
+        modifyText("build.gradle.kts") { str ->
+            str.replace(
+                "implementation(compose.components.resources)",
+                "//implementation(compose.components.resources)"
+            )
+        }
+        gradle("prepareKotlinIdeaImport").checks {
+            check.taskSuccessful(":generateComposeResClass")
+            assert(!file("build/generated/compose/resourceGenerator/kotlin/app/group/resources_test/generated/resources/Res.kt").exists())
+        }
+
+        gradle("prepareKotlinIdeaImport", "-Pcompose.resources.always.generate.accessors=true").checks {
+            check.taskSuccessful(":generateComposeResClass")
+            assert(file("build/generated/compose/resourceGenerator/kotlin/app/group/resources_test/generated/resources/Res.kt").exists())
+        }
+
+        modifyText("build.gradle.kts") { str ->
+            str.replace(
+                "//implementation(compose.components.resources)",
+                "implementation(compose.components.resources)"
+            )
+        }
+        gradle("prepareKotlinIdeaImport").checks {
+            check.taskUpToDate(":generateComposeResClass")
+            assert(file("build/generated/compose/resourceGenerator/kotlin/app/group/resources_test/generated/resources/Res.kt").exists())
+        }
+
+        modifyText("build.gradle.kts") { str ->
+            str.replace(
+                "group = \"app.group\"",
+                "group = \"io.company\""
+            )
+        }
+        gradle("prepareKotlinIdeaImport").checks {
+            check.taskSuccessful(":generateComposeResClass")
+            assert(!file("build/generated/compose/resourceGenerator/kotlin/app/group/resources_test/generated/resources/Res.kt").exists())
+            assert(file("build/generated/compose/resourceGenerator/kotlin/io/company/resources_test/generated/resources/Res.kt").exists())
+        }
+    }
+
     @Test
     fun testEmptyResClass(): Unit = with(testProject("misc/emptyResources")) {
         gradle("generateComposeResClass").checks {

gradle-plugins/compose/src/test/kotlin/org/jetbrains/compose/test/utils/assertUtils.kt

@@ -57,6 +57,10 @@ internal class BuildResultChecks(private val result: BuildResult) {
         taskOutcome(task, TaskOutcome.FAILED)
     }
 
+    fun taskUpToDate(task: String) {
+        taskOutcome(task, TaskOutcome.UP_TO_DATE)
+    }
+
     fun taskFromCache(task: String) {
         taskOutcome(task, TaskOutcome.FROM_CACHE)
     }

gradle-plugins/compose/src/test/test-projects/misc/commonResources/build.gradle.kts

@@ -21,7 +21,6 @@ kotlin {
             dependencies {
                 implementation(compose.runtime)
                 implementation(compose.material)
-                @OptIn(org.jetbrains.compose.ExperimentalComposeLibrary::class)
                 implementation(compose.components.resources)
             }
         }