feat: concat constant strings (#1014)

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

@@ -0,0 +1,41 @@
+package jadx.tests.integration.others;
+
+import org.junit.jupiter.api.Test;
+
+import jadx.tests.api.IntegrationTest;
+
+import static jadx.tests.api.utils.assertj.JadxAssertions.assertThat;
+
+public class TestConstStringConcat extends IntegrationTest {
+
+	@SuppressWarnings("StringBufferReplaceableByString")
+	public static class TestCls {
+		public String test1(int value) {
+			return new StringBuilder().append("Value").append(" equals ").append(value).toString();
+		}
+
+		public String test2() {
+			return new StringBuilder().append("App ").append("version: ").append(1).append('.').append(2).toString();
+		}
+
+		public String test3(String name, int value) {
+			return "value " + name + " = " + value;
+		}
+
+		public void check() {
+			assertThat(test1(7)).isEqualTo("Value equals 7");
+			assertThat(test2()).isEqualTo("App version: 1.2");
+			assertThat(test3("v", 4)).isEqualTo("value v = 4");
+		}
+	}
+
+	@Test
+	public void test() {
+		noDebugInfo();
+		assertThat(getClassNode(TestCls.class))
+				.code()
+				.containsOne("return \"Value equals \" + ")
+				.containsOne("return \"App version: 1.2\";")
+				.containsOne("return \"value \" + str + \" = \" + i;");
+	}
+}

jadx-core/src/test/java/jadx/tests/integration/others/TestStringBuilderElimination2.java

@@ -14,6 +14,7 @@ import static org.hamcrest.MatcherAssert.assertThat;
  *
  * @author Jan Peter Stotz
  */
+@SuppressWarnings("StringBufferReplaceableByString")
 public class TestStringBuilderElimination2 extends IntegrationTest {
 
 	public static class TestCls1 {
@@ -27,7 +28,7 @@ public class TestStringBuilderElimination2 extends IntegrationTest {
 	public void test1() {
 		ClassNode cls = getClassNode(TestStringBuilderElimination2.TestCls1.class);
 		String code = cls.getCode().toString();
-		assertThat(code, containsString("return \"[init]\" + \"a1\" + 'c' + 2 + 0L + 1.0f + 2.0d + true;"));
+		assertThat(code, containsString("return \"[init]a1c201.02.0true\";"));
 	}
 
 	public static class TestCls2 {
@@ -49,7 +50,7 @@ public class TestStringBuilderElimination2 extends IntegrationTest {
 	public void test2() {
 		ClassNode cls = getClassNode(TestStringBuilderElimination2.TestCls2.class);
 		String code = cls.getCode().toString();
-		assertThat(code, containsString("return \"[init]\" + \"a1\" + 'c' + 1 + 2L + 1.0f + 2.0d + true;"));
+		assertThat(code, containsString("return \"[init]a1c121.02.0true\";"));
 	}
 
 	public static class TestClsStringUtilsReverse {