core: fix classes import naming

jadx-core/src/main/java/jadx/core/codegen/ClassGen.java

@@ -13,6 +13,7 @@ import jadx.core.dex.info.ClassInfo;
 import jadx.core.dex.instructions.args.ArgType;
 import jadx.core.dex.instructions.args.InsnArg;
 import jadx.core.dex.nodes.ClassNode;
+import jadx.core.dex.nodes.DexNode;
 import jadx.core.dex.nodes.FieldNode;
 import jadx.core.dex.nodes.MethodNode;
 import jadx.core.dex.nodes.parser.FieldValueAttr;
@@ -314,7 +315,7 @@ public class ClassGen {
 	}
 
 	public String useClass(ClassInfo classInfo) {
-		String baseClass = useClassInternal(classInfo);
+		String baseClass = useClassInternal(cls.getClassInfo(), classInfo);
 		ArgType[] generics = classInfo.getType().getGenericTypes();
 		if (generics != null) {
 			StringBuilder sb = new StringBuilder();
@@ -338,46 +339,68 @@ public class ClassGen {
 		}
 	}
 
-	private String useClassInternal(ClassInfo classInfo) {
-		if (parentGen != null)
-			return parentGen.useClassInternal(classInfo);
-
+	private String useClassInternal(ClassInfo useCls, ClassInfo classInfo) {
+		if (parentGen != null) {
+			return parentGen.useClassInternal(useCls, classInfo);
+		}
 		String clsStr = classInfo.getFullName();
-		if (fallback)
+		if (fallback) {
 			return clsStr;
-
+		}
 		String shortName = classInfo.getShortName();
-
 		if (classInfo.getPackage().equals("java.lang") && classInfo.getParentClass() == null) {
 			return shortName;
 		} else {
 			// don't add import if this class inner for current class
-			if (isInner(classInfo, cls.getClassInfo()))
+			if (isClassInnerFor(classInfo, useCls)) {
 				return shortName;
-
+			}
 			// don't add import if this class from same package
-			if (classInfo.getPackage().equals(cls.getPackage()))
+			if (classInfo.getPackage().equals(useCls.getPackage()) && !classInfo.isInner()) {
 				return shortName;
-
+			}
+			if (classInfo.getPackage().equals(useCls.getPackage())) {
+				clsStr = classInfo.getNameWithoutPackage();
+			}
+			if (searchCollision(cls.dex(), useCls, shortName)) {
+				return clsStr;
+			}
 			for (ClassInfo cls : imports) {
 				if (!cls.equals(classInfo)) {
-					if (cls.getShortName().equals(shortName))
+					if (cls.getShortName().equals(shortName)) {
 						return clsStr;
 					}
 				}
+			}
 			imports.add(classInfo);
 			return shortName;
 		}
 	}
 
-	private boolean isInner(ClassInfo inner, ClassInfo parent) {
+	private static boolean isClassInnerFor(ClassInfo inner, ClassInfo parent) {
 		if (inner.isInner()) {
 			ClassInfo p = inner.getParentClass();
-			return p.equals(parent) || isInner(p, parent);
+			return p.equals(parent) || isClassInnerFor(p, parent);
 		}
 		return false;
 	}
 
+	private static boolean searchCollision(DexNode dex, ClassInfo useCls, String shortName) {
+		if (useCls == null) {
+			return false;
+		}
+		if (useCls.getShortName().equals(shortName)) {
+			return true;
+		}
+		ClassNode classNode = dex.resolveClass(useCls);
+		for (ClassNode inner : classNode.getInnerClasses()) {
+			if (inner.getShortName().equals(shortName)) {
+				return true;
+			}
+		}
+		return searchCollision(dex, useCls.getParentClass(), shortName);
+	}
+
 	private void insertSourceFileInfo(CodeWriter code, AttrNode node) {
 		IAttribute sourceFileAttr = node.getAttributes().get(AttributeType.SOURCE_FILE);
 		if (sourceFileAttr != null) {

jadx-samples/src/main/java/jadx/samples/TestInnerNames.java

@@ -0,0 +1,36 @@
+package jadx.samples;
+
+public class TestInnerNames extends AbstractTest {
+
+	public int D;
+
+	public class A extends TestInner.MyThread {
+		public A(String name) {
+			super(name);
+		}
+	}
+
+	public class B extends A {
+		public B(String name) {
+			super(name);
+		}
+
+		public class C extends TestInner2.B {
+		}
+	}
+
+	public class C extends TestInner2.B {
+	}
+
+	public class D extends TestInner2.D {
+	}
+
+	@Override
+	public boolean testRun() throws Exception {
+		return true;
+	}
+
+	public static void main(String[] args) throws Exception {
+		new TestInnerNames().testRun();
+	}
+}