Metacompiler fix (#1024)

* Fix metacompiler when installed together with KLighD.

Previously the metacompiler would fail to compile some melk files due to
the name already being defined. This modifies the validator to
explicitly only check in paths containing "src".

* add missing newline

plugins/org.eclipse.elk.core.meta.ui/src/org/eclipse/elk/core/meta/ui/MetaDataUiModule.xtend

@@ -9,11 +9,24 @@
  *******************************************************************************/
 package org.eclipse.elk.core.meta.ui
 
+import org.eclipse.elk.core.meta.validation.MelkUniqueClassNameValidator
 import org.eclipse.xtend.lib.annotations.FinalFieldsConstructor
+import org.eclipse.xtext.service.SingletonBinding
 
 /**
  * Use this class to register components to be used within the Eclipse IDE.
  */
 @FinalFieldsConstructor
 class MetaDataUiModule extends AbstractMetaDataUiModule {
+
+// If the Metacompiler has hiccups this can be used to always generate the Java source files, 
+// regardles of any errors.
+//    override bindIShouldGenerate() {
+//        return Always
+//    }
+
+    @SingletonBinding(eager = true)
+    override bindUniqueClassNameValidator() {
+        return MelkUniqueClassNameValidator
+    }
 }

plugins/org.eclipse.elk.core.meta/src/org/eclipse/elk/core/meta/MetaDataRuntimeModule.xtend

@@ -15,6 +15,8 @@ import org.eclipse.elk.core.meta.jvmmodel.MelkDocumentationGenerator
 import org.eclipse.xtext.generator.IOutputConfigurationProvider
 import org.eclipse.xtext.generator.OutputConfiguration
 import org.eclipse.xtext.generator.OutputConfigurationProvider
+import org.eclipse.elk.core.meta.validation.MelkUniqueClassNameValidator
+import org.eclipse.xtext.service.SingletonBinding
 
 /**
  * Use this class to register components to be used at runtime / without the Equinox extension registry.
@@ -25,6 +27,11 @@ class MetaDataRuntimeModule extends AbstractMetaDataRuntimeModule {
         return MelkDocumentationGenerator
     }
 
+    @SingletonBinding(eager = true)
+    override bindUniqueClassNameValidator() {
+        return MelkUniqueClassNameValidator
+    }
+
     // register MelkOutputConfigurationProvider that inserts a configuration used to read files in the project
     override configure(Binder binder) {
         super.configure(binder)

plugins/org.eclipse.elk.core.meta/src/org/eclipse/elk/core/meta/validation/MelkUniqueClassNameValidator.xtend

@@ -0,0 +1,34 @@
+/*******************************************************************************
+ * Copyright (c) 2024 mka and others.
+ * 
+ * This program and the accompanying materials are made available under the
+ * terms of the Eclipse Public License 2.0 which is available at
+ * http://www.eclipse.org/legal/epl-2.0.
+ * 
+ * SPDX-License-Identifier: EPL-2.0 
+ *******************************************************************************/
+package org.eclipse.elk.core.meta.validation
+
+import com.google.inject.Inject
+import org.eclipse.xtext.common.types.JvmDeclaredType
+import org.eclipse.xtext.common.types.TypesPackage
+import org.eclipse.xtext.naming.QualifiedName
+import org.eclipse.xtext.xbase.validation.UniqueClassNameValidator
+import org.eclipse.xtext.resource.impl.ResourceDescriptionsProvider
+
+/**
+ * Overwrites the UniqueClassNameValidator to only check for melk files in src folders. This probably
+ * prevents some special use cases where ELK is used as a library and a new melk file is created.
+ *
+ */
+class MelkUniqueClassNameValidator extends UniqueClassNameValidator {
+
+    @Inject
+    var ResourceDescriptionsProvider resourceDescriptionsProvider;
+
+    override doCheckUniqueName(QualifiedName name, JvmDeclaredType type) {
+        val index = resourceDescriptionsProvider.getResourceDescriptions(type.eResource())
+        val others = index.getExportedObjects(TypesPackage.Literals.JVM_DECLARED_TYPE, name, false)
+        return checkUniqueInIndex(type, others.filter[it.EObjectURI.segments.exists[it.contains("src")]])
+    }
+}