fix: force cast for null args in method invoke (temp fix for #724)

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

@@ -769,7 +769,7 @@ public class InsnGen {
 				if (!firstArg) {
 					code.add(", ");
 				}
-				boolean cast = overloaded && processOverloadedArg(code, insn, callMth, arg, i - startArgNum);
+				boolean cast = addArgCast(code, insn, callMth, arg, i - startArgNum, overloaded);
 				if (!cast && i == argsCount - 1 && processVarArg(code, callMth, arg)) {
 					continue;
 				}
@@ -781,42 +781,47 @@ public class InsnGen {
 	}
 
 	/**
-	 * Add additional cast for overloaded method argument.
+	 * Add additional cast for method argument.
 	 */
-	private boolean processOverloadedArg(CodeWriter code, InsnNode insn, MethodNode callMth, InsnArg arg, int origPos) {
-		List<ArgType> argTypes = callMth.getArgTypes();
-		ArgType origType = argTypes.get(origPos);
-		if (origType.isGenericType() && !callMth.getParentClass().equals(mth.getParentClass())) {
-			// cancel cast
-			return false;
-		}
+	private boolean addArgCast(CodeWriter code, InsnNode insn, @Nullable MethodNode callMth,
+			InsnArg arg, int origPos, boolean overloaded) {
 		ArgType castType = null;
-		if (insn instanceof CallMthInterface && origType.containsGenericType()) {
-			ArgType clsType;
-			CallMthInterface mthCall = (CallMthInterface) insn;
-			RegisterArg instanceArg = mthCall.getInstanceArg();
-			if (instanceArg != null) {
-				clsType = instanceArg.getType();
-			} else {
-				clsType = mthCall.getCallMth().getDeclClass().getType();
+		if (callMth != null) {
+			List<ArgType> argTypes = callMth.getArgTypes();
+			ArgType origType = argTypes.get(origPos);
+			if (origType.isGenericType() && !callMth.getParentClass().equals(mth.getParentClass())) {
+				// cancel cast
+				return false;
 			}
-			ArgType replacedType = TypeUtils.replaceClassGenerics(root, clsType, origType);
-			if (replacedType != null) {
-				castType = replacedType;
+			if (insn instanceof CallMthInterface && origType.containsGenericType()) {
+				ArgType clsType;
+				CallMthInterface mthCall = (CallMthInterface) insn;
+				RegisterArg instanceArg = mthCall.getInstanceArg();
+				if (instanceArg != null) {
+					clsType = instanceArg.getType();
+				} else {
+					clsType = mthCall.getCallMth().getDeclClass().getType();
+				}
+				ArgType replacedType = TypeUtils.replaceClassGenerics(root, clsType, origType);
+				if (replacedType != null) {
+					castType = replacedType;
+				}
+				if (castType == null) {
+					ArgType invReplType = TypeUtils.replaceMethodGenerics(root, insn, origType);
+					if (invReplType != null) {
+						castType = invReplType;
+					}
+				}
 			}
 			if (castType == null) {
-				ArgType invReplType = TypeUtils.replaceMethodGenerics(root, insn, origType);
-				if (invReplType != null) {
-					castType = invReplType;
-				}
+				castType = origType;
 			}
-		}
-		if (castType == null) {
-			castType = origType;
+		} else {
+			castType = arg.getType();
 		}
 		// TODO: check castType for left type variables
 
-		if (isCastNeeded(arg, castType)) {
+		if (isCastNeeded(arg, castType, overloaded)) {
 			code.add('(');
 			useType(code, castType);
 			code.add(") ");
@@ -825,7 +830,7 @@ public class InsnGen {
 		return false;
 	}
 
-	private boolean isCastNeeded(InsnArg arg, ArgType origType) {
+	private boolean isCastNeeded(InsnArg arg, ArgType origType, boolean overloaded) {
 		ArgType argType = arg.getType();
 		if (arg.isLiteral() && ((LiteralArg) arg).getLiteral() == 0
 				&& (argType.isObject() || argType.isArray())) {
@@ -834,7 +839,7 @@ public class InsnGen {
 		if (argType.equals(origType)) {
 			return false;
 		}
-		return true;
+		return overloaded;
 	}
 
 	/**

jadx-core/src/test/java/jadx/tests/integration/invoke/TestCastInOverloadedInvoke2.java

+package jadx.tests.integration.invoke;
+
+import org.junit.jupiter.api.Test;
+
+import jadx.core.dex.nodes.ClassNode;
+import jadx.tests.api.SmaliTest;
+
+import static jadx.tests.api.utils.JadxMatchers.containsOne;
+import static org.hamcrest.MatcherAssert.assertThat;
+
+public class TestCastInOverloadedInvoke2 extends SmaliTest {
+
+	@Test
+	public void test() {
+		disableCompilation();
+
+		ClassNode cls = getClassNodeFromSmali();
+		String code = cls.getCode().toString();
+
+		assertThat(code, containsOne("new Intent().putExtra(\"param\", (Parcelable) null);"));
+	}
+}

jadx-core/src/test/java/jadx/tests/integration/others/TestDeboxing2.java

@@ -39,11 +39,10 @@ public class TestDeboxing2 extends IntegrationTest {
 		assertThat(code, containsOne("l = 0L;"));
 
 		// checks for 'check' method
-		assertThat(code, containsOne("test(null)"));
+		assertThat(code, containsOne("test((Long) null)")); // TODO: cast not needed
 		assertThat(code, containsOne("test(0L)"));
 		assertThat(code, countString(2, "is(0L)"));
 		assertThat(code, containsOne("test(7L)"));
 		assertThat(code, containsOne("is(7L)"));
-
 	}
 }

jadx-core/src/test/smali/invoke/TestCastInOverloadedInvoke2.smali

+.class public Linvoke/TestCastInOverloadedInvoke2;
+.super Ljava/lang/Object;
+
+.method public test()V
+    .locals 3
+
+    new-instance v0, Landroid/content/Intent;
+
+    invoke-direct {v0}, Landroid/content/Intent;-><init>()V
+
+    const-string v1, "param"
+
+    const/4 v2, 0x0
+
+    invoke-virtual {v0, v1, v2}, Landroid/content/Intent;->putExtra(Ljava/lang/String;Landroid/os/Parcelable;)Landroid/content/Intent;
+
+    return-void
+.end method