fix: Properly support isolated projects

gradle-project-plugin/src/main/kotlin/de/siphalor/minecraft_modding_toolkit/gradle/project_plugin/SmcmtkLoomProxy.kt

@@ -1,5 +1,7 @@
 package de.siphalor.minecraft_modding_toolkit.gradle.project_plugin
 
+import net.fabricmc.loom.LoomNoRemapGradlePlugin
+import net.fabricmc.loom.LoomRemapGradlePlugin
 import net.fabricmc.loom.api.LoomGradleExtensionAPI
 import org.gradle.api.Project
 import org.gradle.api.artifacts.MinimalExternalModuleDependency
@@ -9,8 +11,38 @@ import org.gradle.api.tasks.SourceSet
 import org.jetbrains.annotations.ApiStatus
 
 @ApiStatus.Internal
-class SmcmtkLoomProxy(val project: Project, loomGradleExtensionApi: Any) {
-	val loom = loomGradleExtensionApi as LoomGradleExtensionAPI
+class SmcmtkLoomProxy(val project: Project, loomGradleExtensionApi: () -> Any?) {
+	val loom by lazy {
+		val extension = loomGradleExtensionApi() ?: throw IllegalStateException(
+			"SMCMTK tried to access Loom extension but it was not present"
+		)
+		extension as LoomGradleExtensionAPI
+	}
+
+	fun hasPlainPlugin(): Boolean {
+		return project.plugins.hasPlugin(LoomNoRemapGradlePlugin::class.java)
+	}
+
+	fun onPlainPlugin(action: () -> Unit) {
+		project.plugins.withType(LoomNoRemapGradlePlugin::class.java) {
+			action()
+		}
+	}
+
+	fun hasRemapPlugin(): Boolean {
+		return project.plugins.hasPlugin(LoomRemapGradlePlugin::class.java)
+	}
+
+	fun onRemapPlugin(action: () -> Unit) {
+		project.plugins.withType(LoomRemapGradlePlugin::class.java) {
+			action()
+		}
+	}
+
+	fun isLoomPlainDetectionIssue(): Boolean {
+		return !project.plugins.hasPlugin(LoomNoRemapGradlePlugin.NAME)
+				&& hasPlainPlugin()
+	}
 
 	fun configureOfficialMojangMappings(parchment: Provider<MinimalExternalModuleDependency>?) {
 		if (parchment == null) {

gradle-project-plugin/src/main/kotlin/de/siphalor/minecraft_modding_toolkit/gradle/project_plugin/SmcmtkProjectPlugin.kt

@@ -15,8 +15,7 @@ import javax.inject.Inject
 
 abstract class SmcmtkProjectPlugin : Plugin<Project> {
 	companion object {
-		private const val LOOM_PLAIN_PLUGIN_ID = "net.fabricmc.fabric-loom"
-		private const val LOOM_REMAP_PLUGIN_ID = "net.fabricmc.fabric-loom-remap"
+		private const val LOOM_SAMPLE_CLASS_NAME = "net.fabricmc.loom.LoomRemapGradlePlugin"
 
 		private val MOD_BASE_CONFIGURATION_NAMES = arrayOf("api", "implementation", "compileOnly", "runtimeOnly", "localRuntime")
 
@@ -29,12 +28,23 @@ abstract class SmcmtkProjectPlugin : Plugin<Project> {
 	@get:Inject
 	protected abstract val projectLayout: ProjectLayout
 
-	private val logger = lazy { Logging.getLogger(javaClass) }
+	private val logger by lazy { Logging.getLogger(javaClass) }
 
 	private lateinit var project: Project
 	private lateinit var extension: SmcmtkProjectExtension
 
-	private var loomProxy = lazy { project.extensions.findByName("loom")?.let { SmcmtkLoomProxy(project, it)} }
+	private var loomPresent = try {
+		Class.forName(LOOM_SAMPLE_CLASS_NAME, false, javaClass.classLoader); true
+	} catch (_: ClassNotFoundException) {
+		false
+	}
+	private val loomProxy by lazy {
+		if (loomPresent) {
+			SmcmtkLoomProxy(project) { project.extensions.findByName("loom") }
+		} else {
+			null
+		}
+	}
 
 	override fun apply(project: Project) {
 		this.project = project
@@ -47,21 +57,28 @@ abstract class SmcmtkProjectPlugin : Plugin<Project> {
 
 		extension.mcProps.convention(minecraftProperties.map { mapOf(*it.entries.map { entry -> entry.key.toString() to entry.value.toString() }.toTypedArray()) })
 
-		project.plugins.withId(LOOM_PLAIN_PLUGIN_ID) {
+		loomProxy?.onPlainPlugin {
 			project.configurations.maybeCreate("namedElements")
 				.extendsFrom(project.configurations.getByName("apiElements"))
+
+			if (loomProxy!!.isLoomPlainDetectionIssue()) {
+				logger.warn("""
+					|Plain loom plugin is applied as a class not via a plugin id, this may cause issues with Loom not disabling remapping.
+					|If you apply the loom plugin through a convention plugin, make sure the convention build uses compileOnly instead of implementation.
+				""".trimMargin())
+			}
 		}
 	}
 
 	fun configureMojangMappings() {
-		project.plugins.withId(LOOM_REMAP_PLUGIN_ID) {
+		loomProxy?.onRemapPlugin {
 			val versionCatalogs = project.extensions.getByType(VersionCatalogsExtension::class.java)
 			val mcLibsCatalog = versionCatalogs.find("mcLibs").orElse(null)
 			val parchment = mcLibsCatalog?.findLibrary("parchment")?.orElse(null)
 
-			loomProxy.value?.configureOfficialMojangMappings(parchment)
+			loomProxy?.configureOfficialMojangMappings(parchment)
 		}
-		project.plugins.withId(LOOM_PLAIN_PLUGIN_ID) {
+		loomProxy?.onPlainPlugin {
 			project.tasks.withType(ProcessResources::class.java).findByName("processResources")?.apply {
 				filesMatching("*.accesswidener") {
 					it.filter { line ->
@@ -77,11 +94,11 @@ abstract class SmcmtkProjectPlugin : Plugin<Project> {
 	}
 
 	fun createModConfigurations(sourceSets: Collection<SourceSet>) {
-		project.plugins.withId(LOOM_REMAP_PLUGIN_ID) {
+		loomProxy?.onRemapPlugin {
 			sourceSets.filter { it.name != "main" }
-				.forEach { sourceSet -> loomProxy.value?.createRemapConfiguration(sourceSet) }
+				.forEach { sourceSet -> loomProxy?.createRemapConfiguration(sourceSet) }
 		}
-		project.plugins.withId(LOOM_PLAIN_PLUGIN_ID) {
+		loomProxy?.onPlainPlugin {
 			sourceSets.forEach { sourceSet ->
 				val prefix = if (sourceSet.name == "main") "" else sourceSet.name
 
@@ -98,31 +115,35 @@ abstract class SmcmtkProjectPlugin : Plugin<Project> {
 	}
 
 	fun configureAccessWidener(file: RegularFile) {
-		logger.value.debug("Configuring access widener {}", file)
+		logger.debug("Configuring access widener {}", file)
 		if (!file.asFile.isFile) {
-			logger.value.debug("Skipping access widener configuration for non-existing file {}", file)
+			logger.debug("Skipping access widener configuration for non-existing file {}", file)
 			return
 		}
 
-		val accessWidenerNamesType = if (project.plugins.hasPlugin(LOOM_PLAIN_PLUGIN_ID)) {
+		if (!loomPresent) {
+			return
+		}
+
+		val accessWidenerNamesType = if (loomProxy?.hasPlainPlugin() ?: false) {
 			"official"
-		} else if (project.plugins.hasPlugin(LOOM_REMAP_PLUGIN_ID)) {
+		} else if (loomProxy?.hasRemapPlugin() ?: false) {
 			"named"
 		} else {
 			null
 		}
 
 		if (accessWidenerNamesType != null) {
-			logger.value.info("Changing access widener names type of $file to $accessWidenerNamesType")
+			logger.info("Changing access widener names type of $file to $accessWidenerNamesType")
 			file.asFile.writeText(file.asFile.readText(Charsets.UTF_8).lines().joinToString("\n") { line ->
 				ACCESS_WIDENER_DECLARATION_PATTERN.matchAt(line, 0)
 					?.let { match -> line.substring(match.range) + accessWidenerNamesType }
 					?: line
 			})
 		} else {
-			logger.value.warn("Could not determine access widener names type for $file")
+			logger.warn("Could not determine access widener names type for $file")
 		}
 
-		loomProxy.value?.setAccessWidenerPath(file)
+		loomProxy?.setAccessWidenerPath(file)
 	}
 }

gradle-settings-plugin/src/main/kotlin/de/siphalor/minecraft_modding_toolkit/gradle/settings_plugin/SmcmtkSettingsPlugin.kt

@@ -61,8 +61,11 @@ abstract class SmcmtkSettingsPlugin : Plugin<Settings> {
             settings.gradle.lifecycle.beforeProject { project ->
                 project.extensions.findByType(ExtraPropertiesExtension::class.java)?.apply {
                     // Loom uses the same jar for both plugin variants (plain and remap) and tries to determine
-                    // which one is in use by checking the plugin manager.
-                    // This doesn't seem to work when using convention plugins, so we're forcing the remapping off here.
+                    // which one is in use by checking the plugin manager by the plugin id.
+                    // This doesn't work when the Loom plugin is in the classpath already due to convention plugins.
+                    // Since in this case Gradle doesn't register the plugin id, we're forcing the remapping off here.
+                    // This notably doesn't work in isolated projects as Loom uses providers.gradleProperty there
+                    // which can't be overwritten programmatically.
                     set("fabric.loom.disableObfuscation", "true")
                     set("fabric.loom.dontRemap", "true")
                 }