fix: handle classes 'super' loop (#1942)

jadx-core/src/main/java/jadx/api/JadxDecompiler.java

@@ -199,6 +199,7 @@ public final class JadxDecompiler implements Closeable {
 	}
 
 	private void loadFinished() {
+		LOG.debug("Load finished");
 		List<JadxPass> list = customPasses.get(JadxAfterLoadPass.TYPE);
 		if (list != null) {
 			for (JadxPass pass : list) {

jadx-core/src/main/java/jadx/core/dex/visitors/OverrideMethodVisitor.java

@@ -2,6 +2,7 @@ package jadx.core.dex.visitors;
 
 import java.util.ArrayList;
 import java.util.HashSet;
+import java.util.LinkedHashSet;
 import java.util.List;
 import java.util.Map;
 import java.util.Objects;
@@ -281,7 +282,7 @@ public class OverrideMethodVisitor extends AbstractVisitor {
 
 	@Nullable
 	private SuperTypesData collectSuperTypes(ClassNode cls) {
-		List<ArgType> superTypes = new ArrayList<>();
+		Set<ArgType> superTypes = new LinkedHashSet<>();
 		Set<String> endTypes = new HashSet<>();
 		collectSuperTypes(cls, superTypes, endTypes);
 		if (superTypes.isEmpty()) {
@@ -290,10 +291,10 @@ public class OverrideMethodVisitor extends AbstractVisitor {
 		if (endTypes.isEmpty()) {
 			throw new JadxRuntimeException("No end types in class hierarchy: " + cls);
 		}
-		return new SuperTypesData(superTypes, endTypes);
+		return new SuperTypesData(new ArrayList<>(superTypes), endTypes);
 	}
 
-	private void collectSuperTypes(ClassNode cls, List<ArgType> superTypes, Set<String> endTypes) {
+	private void collectSuperTypes(ClassNode cls, Set<ArgType> superTypes, Set<String> endTypes) {
 		RootNode root = cls.root();
 		int k = 0;
 		ArgType superClass = cls.getSuperClass();
@@ -308,21 +309,24 @@ public class OverrideMethodVisitor extends AbstractVisitor {
 		}
 	}
 
-	private int addSuperType(RootNode root, List<ArgType> superTypesMap, Set<String> endTypes, ArgType superType) {
+	private int addSuperType(RootNode root, Set<ArgType> superTypes, Set<String> endTypes, ArgType superType) {
 		if (Objects.equals(superType, ArgType.OBJECT)) {
 			return 0;
 		}
-		superTypesMap.add(superType);
+		if (!superTypes.add(superType)) {
+			// found 'super' loop, stop processing
+			return 0;
+		}
 		ClassNode classNode = root.resolveClass(superType);
 		if (classNode != null) {
-			collectSuperTypes(classNode, superTypesMap, endTypes);
+			collectSuperTypes(classNode, superTypes, endTypes);
 			return 1;
 		}
 		ClspClass clsDetails = root.getClsp().getClsDetails(superType);
 		if (clsDetails != null) {
 			int k = 0;
 			for (ArgType parentType : clsDetails.getParents()) {
-				k += addSuperType(root, superTypesMap, endTypes, parentType);
+				k += addSuperType(root, superTypes, endTypes, parentType);
 			}
 			if (k == 0) {
 				endTypes.add(superType.getObject());

jadx-core/src/main/java/jadx/core/dex/visitors/ShadowFieldVisitor.java

@@ -3,8 +3,10 @@ package jadx.core.dex.visitors;
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.HashMap;
+import java.util.HashSet;
 import java.util.List;
 import java.util.Map;
+import java.util.Set;
 
 import org.jetbrains.annotations.Nullable;
 
@@ -107,8 +109,14 @@ public class ShadowFieldVisitor extends AbstractVisitor {
 
 	private static List<FieldNode> collectAllInstanceFields(ClassNode cls) {
 		List<FieldNode> fieldsList = new ArrayList<>();
+		Set<ClassNode> visited = new HashSet<>();
 		ClassNode currentClass = cls;
 		while (currentClass != null) {
+			if (!visited.add(currentClass)) {
+				String msg = "Found 'super' loop in classes: " + visited;
+				visited.forEach(c -> c.addWarnComment(msg));
+				return fieldsList;
+			}
 			for (FieldNode field : currentClass.getFields()) {
 				if (!field.getAccessFlags().isStatic()) {
 					fieldsList.add(field);

jadx-core/src/test/java/jadx/tests/integration/others/TestSuperLoop.java

@@ -0,0 +1,40 @@
+package jadx.tests.integration.others;
+
+import java.util.List;
+
+import org.junit.jupiter.api.Test;
+
+import jadx.core.dex.nodes.ClassNode;
+import jadx.tests.api.SmaliTest;
+
+import static jadx.tests.api.utils.assertj.JadxAssertions.assertThat;
+
+@SuppressWarnings("CommentedOutCode")
+public class TestSuperLoop extends SmaliTest {
+	// @formatter:off
+	/*
+		public class A extends B {
+			public int a;
+		}
+
+		public class B extends A {
+			public int b;
+		}
+	*/
+	// @formatter:on
+
+	@Test
+	public void test() {
+		allowWarnInCode();
+		disableCompilation();
+
+		List<ClassNode> clsList = loadFromSmaliFiles();
+		assertThat(searchCls(clsList, "A"))
+				.code()
+				.containsOne("public class A extends B {");
+
+		assertThat(searchCls(clsList, "B"))
+				.code()
+				.containsOne("public class B extends A {");
+	}
+}

jadx-core/src/test/smali/others/TestSuperLoop/A.smali

@@ -0,0 +1,4 @@
+.class public LA;
+.super LB;
+
+.field public a:I

jadx-core/src/test/smali/others/TestSuperLoop/B.smali

@@ -0,0 +1,4 @@
+.class public LB;
+.super LA;
+
+.field public b:I