feat: select better class from duplicates (#2701)(PR #2702)

* select the right class in in case of duplicate

* select correct class in gui in case of duplication

* fix code format

---------

Co-authored-by: Jean-Marie 'Histausse' Mineau <histausse@protonmail.com>

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

@@ -543,9 +543,10 @@ public final class JadxDecompiler implements Closeable {
 			return foundPkg;
 		}
 		List<JavaClass> clsList = Utils.collectionMap(pkg.getClasses(), this::convertClassNode);
+		List<JavaClass> clsListNoDup = Utils.collectionMap(pkg.getClassesNoDup(), this::convertClassNode);
 		int subPkgsCount = pkg.getSubPackages().size();
 		List<JavaPackage> subPkgs = subPkgsCount == 0 ? Collections.emptyList() : new ArrayList<>(subPkgsCount);
-		JavaPackage javaPkg = new JavaPackage(pkg, clsList, subPkgs);
+		JavaPackage javaPkg = new JavaPackage(pkg, clsList, clsListNoDup, subPkgs);
 		if (subPkgsCount != 0) {
 			// add subpackages after parent to avoid endless recursion
 			for (PackageNode subPackage : pkg.getSubPackages()) {

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

@@ -15,11 +15,17 @@ import jadx.core.dex.nodes.PackageNode;
 public final class JavaPackage implements JavaNode, Comparable<JavaPackage> {
 	private final PackageNode pkgNode;
 	private final List<JavaClass> classes;
+	private final List<JavaClass> clsListNoDup;
 	private final List<JavaPackage> subPkgs;
 
 	JavaPackage(PackageNode pkgNode, List<JavaClass> classes, List<JavaPackage> subPkgs) {
+		this(pkgNode, classes, classes, subPkgs);
+	}
+
+	JavaPackage(PackageNode pkgNode, List<JavaClass> classes, List<JavaClass> clsListNoDup, List<JavaPackage> subPkgs) {
 		this.pkgNode = pkgNode;
 		this.classes = classes;
+		this.clsListNoDup = clsListNoDup;
 		this.subPkgs = subPkgs;
 	}
 
@@ -49,6 +55,10 @@ public final class JavaPackage implements JavaNode, Comparable<JavaPackage> {
 		return classes;
 	}
 
+	public List<JavaClass> getClassesNoDup() {
+		return clsListNoDup;
+	}
+
 	public boolean isRoot() {
 		return pkgNode.isRoot();
 	}

jadx-core/src/main/java/jadx/core/dex/nodes/PackageNode.java

@@ -3,6 +3,7 @@ package jadx.core.dex.nodes;
 import java.util.ArrayList;
 import java.util.List;
 import java.util.Objects;
+import java.util.stream.Collectors;
 
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
@@ -188,6 +189,14 @@ public class PackageNode extends LineAttrNode
 		return classes;
 	}
 
+	public List<ClassNode> getClassesNoDup() {
+		return classes.stream()
+				.map(ClassNode::getClassInfo)
+				.collect(Collectors.toSet())
+				.stream()
+				.map(e -> root.resolveClass(e)).collect(Collectors.toList());
+	}
+
 	public JavaPackage getJavaNode() {
 		return javaNode;
 	}

jadx-core/src/main/java/jadx/core/dex/nodes/RootNode.java

@@ -217,8 +217,43 @@ public class RootNode {
 
 	public void addClassNode(ClassNode clsNode) {
 		classes.add(clsNode);
-		clsMap.put(clsNode.getClassInfo(), clsNode);
-		rawClsMap.put(clsNode.getRawName(), clsNode);
+		ClassNode prevClsNode = clsMap.get(clsNode.getClassInfo());
+		if (prevClsNode == null) {
+			clsMap.put(clsNode.getClassInfo(), clsNode);
+			rawClsMap.put(clsNode.getRawName(), clsNode);
+		} else {
+			String prevFileName = prevClsNode.getInputFileName();
+			String fileName = clsNode.getInputFileName();
+
+			boolean prevFileNameIsValid = prevFileName.matches("classes[1-9]\\d*.dex") && !prevFileName.equals("classes1.dex");
+			boolean fileNameIsValid = fileName.matches("classes[1-9]\\d*.dex") && !fileName.equals("classes1.dex");
+
+			ClassNode newClsNode = clsNode;
+			// classes.dex has precedence
+			if (fileName.equals("classes.dex")) {
+				newClsNode = clsNode;
+			} else if (prevFileName.equals("classes.dex")) {
+				newClsNode = prevClsNode;
+			} else if (prevFileNameIsValid && !fileNameIsValid) {
+				// valid dex names have precedence
+				newClsNode = prevClsNode;
+			} else if (!prevFileNameIsValid && fileNameIsValid) {
+				newClsNode = clsNode;
+			} else if (prevFileNameIsValid && fileNameIsValid) {
+				// if both are valid, the lower index has precedence
+				long index = Long.parseLong(fileName.substring(7, fileName.length() - 4));
+				long prevIndex = Long.parseLong(prevFileName.substring(7, prevFileName.length() - 4));
+
+				if (index < prevIndex) {
+					newClsNode = clsNode;
+				} else {
+					newClsNode = prevClsNode;
+				}
+			}
+
+			clsMap.put(newClsNode.getClassInfo(), newClsNode);
+			rawClsMap.put(newClsNode.getRawName(), newClsNode);
+		}
 	}
 
 	public void loadResources(ResourcesLoader resLoader, List<ResourceFile> resources) {

jadx-gui/src/main/java/jadx/gui/utils/pkgs/PackageHelper.java

@@ -174,7 +174,7 @@ public class PackageHelper {
 		if (synthetic) {
 			classes = Collections.emptyList();
 		} else {
-			classes = Utils.collectionMap(javaPkg.getClasses(), nodeCache::makeFrom);
+			classes = Utils.collectionMap(javaPkg.getClassesNoDup(), nodeCache::makeFrom);
 			classes.sort(CLASS_COMPARATOR);
 		}
 		return nodeCache.newJPackage(javaPkg, synthetic, pkgEnabled, classes);