From e133c1e8d8a9e95532c688d4160840ce341859e1 Mon Sep 17 00:00:00 2001
From: Pouryafard75 <pouryafard75@gmail.com>
Date: Mon, 6 Jan 2025 16:44:36 -0500
Subject: [PATCH] ASTDiff: Fixes
 https://github.com/tsantalis/RefactoringMiner/issues/846

---
 .../astDiff/matchers/wrappers/FieldDeclarationMatcher.java   | 4 +++-
 .../refactoringminer/astDiff/utils/TreeUtilFunctions.java    | 5 +++--
 2 files changed, 6 insertions(+), 3 deletions(-)

diff --git a/src/main/java/org/refactoringminer/astDiff/matchers/wrappers/FieldDeclarationMatcher.java b/src/main/java/org/refactoringminer/astDiff/matchers/wrappers/FieldDeclarationMatcher.java
index 5de0b7639c..17387ee51a 100644
--- a/src/main/java/org/refactoringminer/astDiff/matchers/wrappers/FieldDeclarationMatcher.java
+++ b/src/main/java/org/refactoringminer/astDiff/matchers/wrappers/FieldDeclarationMatcher.java
@@ -98,10 +98,12 @@ private void processFieldDeclaration(Tree srcTree, Tree dstTree, UMLAttribute sr
         new JavaDocMatcher(optimizationData, srcUMLAttribute.getJavadoc(), dstUMLAttribute.getJavadoc(), umlJavadocDiff)
                 .match(srcTree, dstTree, mappingStore);
         if (srcVarDeclaration != null && dstVarDeclaration != null)
-            mappingStore.addMapping(srcVarDeclaration.getChild(0),dstVarDeclaration.getChild(0));
+            if (!srcVarDeclaration.getChildren().isEmpty() && !dstVarDeclaration.getChildren().isEmpty())
+                mappingStore.addMapping(srcVarDeclaration.getChild(0),dstVarDeclaration.getChild(0));
     }
 
     private void matchFieldAllModifiers(Tree srcFieldDeclaration, Tree dstFieldDeclaration, UMLAttribute srcUMLAttribute, UMLAttribute dstUMLAttribute, ExtendedMultiMappingStore mappingStore) {
+        if (srcFieldDeclaration == null || dstFieldDeclaration == null) return;
         matchModifiersForField(srcFieldDeclaration,dstFieldDeclaration,srcUMLAttribute.getVisibility().toString(),dstUMLAttribute.getVisibility().toString(),mappingStore);
         if (srcUMLAttribute.isFinal() && dstUMLAttribute.isFinal())
             matchModifierForField(srcFieldDeclaration,dstFieldDeclaration,Constants.FINAL,mappingStore);
diff --git a/src/main/java/org/refactoringminer/astDiff/utils/TreeUtilFunctions.java b/src/main/java/org/refactoringminer/astDiff/utils/TreeUtilFunctions.java
index bbe33ca14b..28b714615a 100644
--- a/src/main/java/org/refactoringminer/astDiff/utils/TreeUtilFunctions.java
+++ b/src/main/java/org/refactoringminer/astDiff/utils/TreeUtilFunctions.java
@@ -298,9 +298,10 @@ public static boolean isFromType(Tree t1, String type) {
 		return t1.getType().name.equals(type);
 	}
 
-	public static Tree findFirstByType(Tree srcFieldDeclaration, String typeName) {
+	public static Tree findFirstByType(Tree inputTree, String typeName) {
+		if (inputTree == null) return null;
 		Tree fieldAnnotation = null;
-		for (Tree child : srcFieldDeclaration.getChildren()) {
+		for (Tree child : inputTree.getChildren()) {
 			if (isFromType(child, typeName)) {
 				fieldAnnotation = child;
 				break;