3 files changed, 42 insertions, 4 deletions

diff --git a/src/core/lombok/eclipse/EclipseAST.java b/src/core/lombok/eclipse/EclipseAST.java
index b45ac72d..d53856af 100644
--- a/src/core/lombok/eclipse/EclipseAST.java
+++ b/src/core/lombok/eclipse/EclipseAST.java
@@ -350,7 +350,7 @@ public class EclipseAST extends AST<EclipseAST, EclipseNode, ASTNode> {
 		if (!changed) clearChanged();
 	}
 	
-	private static boolean isComplete(CompilationUnitDeclaration unit) {
+	public static boolean isComplete(CompilationUnitDeclaration unit) {
 		return (unit.bits & ASTNode.HasAllMethodBodies) != 0;
 	}
 	
diff --git a/src/core/lombok/eclipse/TransformEclipseAST.java b/src/core/lombok/eclipse/TransformEclipseAST.java
index 6fcde937..59a0709e 100644
--- a/src/core/lombok/eclipse/TransformEclipseAST.java
+++ b/src/core/lombok/eclipse/TransformEclipseAST.java
@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2009-2019 The Project Lombok Authors.
+ * Copyright (C) 2009-2020 The Project Lombok Authors.
  * 
  * Permission is hereby granted, free of charge, to any person obtaining a copy
  * of this software and associated documentation files (the "Software"), to deal
@@ -24,6 +24,9 @@ package lombok.eclipse;
 import static lombok.eclipse.handlers.EclipseHandlerUtil.*;
 
 import java.lang.reflect.Field;
+import java.util.Collections;
+import java.util.Map;
+import java.util.WeakHashMap;
 
 import lombok.ConfigurationKeys;
 import lombok.core.LombokConfiguration;
@@ -63,6 +66,7 @@ public class TransformEclipseAST {
 	
 	public static boolean disableLombok = false;
 	private static final HistogramTracker lombokTracker;
+	private static Map<CompilationUnitDeclaration, State> transformationStates = Collections.synchronizedMap(new WeakHashMap<CompilationUnitDeclaration, State>());
 	
 	static {
 		String v = System.getProperty("lombok.histogram");
@@ -130,6 +134,30 @@ public class TransformEclipseAST {
 	}
 	
 	/**
+	 * Check if lombok already handled the given AST. This method will return
+	 * <code>true</code> once for diet mode and once for full mode.
+	 * 
+	 * The reason for this is that Eclipse invokes the transform method multiple
+	 * times during compilation and it is enough to transform it once and not
+	 * repeat the whole thing over and over again.
+	 * 
+	 * @param ast The AST node belonging to the compilation unit (java speak for a single source file).
+	 * @return <code>true</code> if this AST was already handled by lombok.
+	 */
+	public static boolean alreadyTransformed(CompilationUnitDeclaration ast) {
+		State state = transformationStates.get(ast);
+		
+		if (state == State.FULL) return true;
+		if (state == State.DIET) {
+			if (!EclipseAST.isComplete(ast)) return true;
+			transformationStates.put(ast, State.FULL);
+		} else {
+			transformationStates.put(ast, State.DIET);
+		}
+		return false;
+	}
+	
+	/**
 	 * This method is called immediately after Eclipse finishes building a CompilationUnitDeclaration, which is
 	 * the top-level AST node when Eclipse parses a source file. The signature is 'magic' - you should not
 	 * change it!
@@ -144,6 +172,7 @@ public class TransformEclipseAST {
 		if (disableLombok) return;
 		
 		if (Symbols.hasSymbol("lombok.disable")) return;
+		if (alreadyTransformed(ast)) return;
 		
 		// Do NOT abort if (ast.bits & ASTNode.HasAllMethodBodies) != 0 - that doesn't work.
 		
@@ -243,4 +272,9 @@ public class TransformEclipseAST {
 			nextPriority = Math.min(nextPriority, handlers.handleAnnotation(top, annotationNode, annotation, priority));
 		}
 	}
+	
+	private static enum State {
+		DIET,
+		FULL
+	}
 }
diff --git a/src/core/lombok/eclipse/handlers/HandleFieldNameConstants.java b/src/core/lombok/eclipse/handlers/HandleFieldNameConstants.java
index 9343011f..cee3912c 100644
--- a/src/core/lombok/eclipse/handlers/HandleFieldNameConstants.java
+++ b/src/core/lombok/eclipse/handlers/HandleFieldNameConstants.java
@@ -171,10 +171,10 @@ public class HandleFieldNameConstants extends EclipseAnnotationHandler<FieldName
 			injectMethod(fieldsType, constructor);
 		}
 		
+		Clinit cli = null;
 		if (genClinit) {
-			Clinit cli = new Clinit(parent.compilationResult);
+			cli = new Clinit(parent.compilationResult);
 			injectMethod(fieldsType, cli);
-			cli.traverse(generatedByVisitor, ((TypeDeclaration) fieldsType.get()).scope);
 		}
 		
 		for (EclipseNode fieldNode : fields) {
@@ -202,5 +202,9 @@ public class HandleFieldNameConstants extends EclipseAnnotationHandler<FieldName
 			injectField(fieldsType, constantField);
 			constantField.traverse(generatedByVisitor, ((TypeDeclaration) fieldsType.get()).initializerScope);
 		}
+		
+		if (genClinit) {
+			cli.traverse(generatedByVisitor, ((TypeDeclaration) fieldsType.get()).scope);
+		}
 	}
 }