fix: ignore external and invalid class names in signature (#2459)(PR #2460)

* fix: erroneous SignatureProcessor resolution of standard non-generic types with Annotation Signatures

* ignore external and invalid class names in signature

---------

Co-authored-by: Skylot <118523+skylot@users.noreply.github.com>

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

@@ -9,6 +9,7 @@ import java.util.Set;
 
 import org.jetbrains.annotations.Nullable;
 
+import jadx.core.deobf.NameMapper;
 import jadx.core.dex.info.MethodInfo;
 import jadx.core.dex.instructions.args.ArgType;
 import jadx.core.dex.nodes.ClassNode;
@@ -167,7 +168,7 @@ public class SignatureProcessor extends AbstractVisitor {
 			}
 			ArgType type = root.getTypeUtils().expandTypeVariables(cls, signatureType);
 			if (!validateParsedType(type, field.getType())) {
-				cls.addWarnComment("Incorrect field signature: " + sp.getSignature());
+				field.addInfoComment("Incorrect field signature: " + sp.getSignature());
 				return;
 			}
 			field.updateType(type);
@@ -256,9 +257,29 @@ public class SignatureProcessor extends AbstractVisitor {
 
 	private boolean validateParsedType(ArgType parsedType, ArgType currentType) {
 		TypeCompareEnum result = root.getTypeCompare().compareTypes(parsedType, currentType);
+		if (result == TypeCompareEnum.UNKNOWN
+				&& parsedType.isObject()
+				&& !validateFullClsName(parsedType.getObject())) {
+			// ignore external invalid class names: may be a reserved words or garbage
+			return false;
+		}
 		return result != TypeCompareEnum.CONFLICT;
 	}
 
+	private boolean validateFullClsName(String fullClsName) {
+		if (!NameMapper.isValidFullIdentifier(fullClsName)) {
+			return false;
+		}
+		if (fullClsName.indexOf('.') > 0) {
+			for (String namePart : fullClsName.split("\\.")) {
+				if (!NameMapper.isValidIdentifier(namePart)) {
+					return false;
+				}
+			}
+		}
+		return true;
+	}
+
 	private boolean validateInnerType(List<ArgType> types) {
 		for (ArgType type : types) {
 			if (!validateInnerType(type)) {

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

@@ -0,0 +1,19 @@
+package jadx.tests.integration.others;
+
+import org.junit.jupiter.api.Test;
+
+import jadx.tests.api.SmaliTest;
+
+import static jadx.tests.api.utils.assertj.JadxAssertions.assertThat;
+
+public class TestIncorrectFieldSignature extends SmaliTest {
+
+	@Test
+	public void test() {
+		assertThat(getClassNodeFromSmali())
+				.code()
+				.containsOne("public static boolean A;")
+				.containsOne("public static Boolean B;")
+				.countString(2, "/* JADX INFO: Incorrect field signature:");
+	}
+}

jadx-core/src/test/smali/others/TestIncorrectFieldSignature.smali

@@ -0,0 +1,18 @@
+.class public Lothers/TestIncorrectFieldSignature;
+.super Ljava/lang/Object;
+
+.field public static A:Z
+	.annotation system Ldalvik/annotation/Signature;
+        value = {
+            "Lint;"
+        }
+    .end annotation
+.end field
+
+.field public static B:Ljava/lang/Boolean;
+	.annotation system Ldalvik/annotation/Signature;
+        value = {
+            "Lpkg/int;"
+        }
+    .end annotation
+.end field