[Java 21] Add tests for exhaustive switch expressions on native enums.

PiperOrigin-RevId: 724475235

jre/java/java/lang/MatchException.java

@@ -0,0 +1,32 @@
+/*
+ * Copyright 2025 Google Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not
+ * use this file except in compliance with the License. You may obtain a copy of
+ * the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations under
+ * the License.
+ */
+package java.lang;
+
+/**
+ * See <a
+ * href="https://docs.oracle.com/en/java/javase/21/docs/api/java.base/java/lang/MatchException.html">the
+ * official Java API doc</a> for details.
+ */
+public class MatchException extends RuntimeException {
+
+  public MatchException() {
+    this("", null);
+  }
+
+  public MatchException(String message, Throwable cause) {
+    super(message, cause);
+  }
+}

jre/java/javasynth/java/lang/IncompatibleClassChangeError.java

@@ -0,0 +1,19 @@
+/*
+ * Copyright 2025 Google Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not
+ * use this file except in compliance with the License. You may obtain a copy of
+ * the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations under
+ * the License.
+ */
+package java.lang;
+
+/** Exists solely to make javac happy. */
+public class IncompatibleClassChangeError extends Error {}

transpiler/javatests/com/google/j2cl/integration/java/jsenum/BUILD

@@ -20,7 +20,11 @@ j2wasm_library(
             "NativeEnums.java",
         ],
     ),
-    javacopts = ["-XepDisableAllChecks"],
+    javacopts = [
+        "-XepDisableAllChecks",
+        "-source 17",
+        "-target 17",
+    ],
     deps = [
         "//jre/java:javaemul_internal_annotations-j2wasm",
         "//third_party:jsinterop-annotations-j2wasm",
@@ -37,4 +41,8 @@ integration_test(
     # Contains JsInterop features which are only applicable for JS output.
     enable_jvm_test = False,
     enable_kt = False,
+    javacopts = [
+        "-source 17",
+        "-target 17",
+    ],
 )

transpiler/javatests/com/google/j2cl/integration/java/jsenum/Main.java

@@ -38,6 +38,7 @@
 import javaemul.internal.annotations.UncheckedCast;
 import javaemul.internal.annotations.Wasm;
 import jsenum.NativeEnums.NativeEnum;
+import jsenum.NativeEnums.NativeEnumWitMissingValues;
 import jsenum.NativeEnums.NativeEnumWithClinit;
 import jsenum.NativeEnums.NumberNativeEnum;
 import jsenum.NativeEnums.StringNativeEnum;
@@ -55,6 +56,8 @@ public class Main {
 
   public static void main(String... args) {
     testNativeJsEnum();
+    // TODO(b/380878051): Enable once bug is fixed.
+    // testNativeJsEnumWithMissingValues();
     testStringNativeJsEnum();
     testCastOnNative();
     testComparableJsEnum();
@@ -158,6 +161,20 @@ private static void testNativeJsEnum() {
     assertTrue(asSeenFromJs(NativeEnum.ACCEPT) == OK_STRING);
   }
 
+  @Wasm("nop") // TODO(b/288145698): Support native JsEnum.
+  private static void testNativeJsEnumWithMissingValues() {
+    try {
+      NativeEnumWitMissingValues e = (NativeEnumWitMissingValues) (Object) NativeEnum.CANCEL;
+      int i =
+          switch (e) {
+            case OK -> 1;
+          };
+      fail();
+    } catch (MatchException | IncompatibleClassChangeError expected) {
+      // Expected behavior.
+    }
+  }
+
   @JsMethod(name = "passThrough")
   @Wasm("nop") // TODO(b/288145698): Support native JsEnum.
   private static native Object asSeenFromJs(NativeEnum s);

transpiler/javatests/com/google/j2cl/integration/java/jsenum/NativeEnums.java

@@ -67,5 +67,10 @@ String getValue() {
     }
   }
 
+  @JsEnum(isNative = true, namespace = "test", name = "NativeEnum")
+  enum NativeEnumWitMissingValues {
+    OK,
+  }
+
   private NativeEnums() {}
 }

transpiler/javatests/com/google/j2cl/integration/java/jsenum/super-wasm/NativeEnums.java

@@ -15,6 +15,7 @@
  */
 package jsenum;
 
+
 /** Placeholders for Wasm. TODO(b/288145698): Native JsEnum is not supported. */
 class NativeEnums {
 
@@ -53,5 +54,9 @@ String getValue() {
     }
   }
 
+  enum NativeEnumWitMissingValues {
+    OK,
+  }
+
   private NativeEnums() {}
 }

transpiler/javatests/com/google/j2cl/readable/java/jsenum/BUILD

@@ -13,5 +13,12 @@ readable_example(
         "*.java",
         "*.native.js",
     ]),
-    deps = ["//third_party:jsinterop-annotations-j2cl"],
+    javacopts = [
+        "-source 14",
+        "-target 14",
+    ],
+    deps = [
+        "//jre/java:javaemul_internal_annotations-j2cl",
+        "//third_party:jsinterop-annotations-j2cl",
+    ],
 )

transpiler/javatests/com/google/j2cl/readable/java/jsenum/Main.java

@@ -19,6 +19,7 @@
 import java.util.Arrays;
 import java.util.List;
 import java.util.Optional;
+import javaemul.internal.annotations.Wasm;
 import jsinterop.annotations.JsEnum;
 import jsinterop.annotations.JsFunction;
 import jsinterop.annotations.JsMethod;
@@ -145,6 +146,19 @@ public static void testJsEnumSwitch() {
     acceptsSupplierOfSupplier(() -> (() -> ComparableJsEnum.ONE));
   }
 
+  // TODO(b/395108282): Remove nop once the bug is fixed.
+  @Wasm("nop")
+  private static void testExhaustiveJsEnumSwitchExpression() {
+    ComparableJsEnum comparableJsEnum =
+        ComparableJsEnum.ONE.getValue() == 1 ? ComparableJsEnum.TWO : null;
+    int i =
+        switch (comparableJsEnum) {
+          case TWO -> 2;
+          case ONE -> 1;
+          case ZERO -> 0;
+        };
+  }
+
   private static void testJsEnumAutoboxingSpecialMethods() {
     StringJsEnum stringJsEnum = StringJsEnum.ONE;
     StringJsEnum nullStringJsEnum = null;

transpiler/javatests/com/google/j2cl/readable/java/jsenum/output_closure/Main.impl.java.js.txt

@@ -91,6 +91,20 @@ class Main extends j_l_Object {
   }));
  }
  /** @nodts */
+ static m_testExhaustiveJsEnumSwitchExpression__void() {
+  let comparableJsEnum = $Overlay.m_getValue__$devirt__jsenum_Main_ComparableJsEnum__int(ComparableJsEnum.ONE) == 1 ? ComparableJsEnum.TWO : /**@type {?ComparableJsEnum}*/ ($Enums.unbox(null, $Overlay));
+  let i = (() =>{
+   switch ((InternalPreconditions.m_checkNotNull__boolean__void(!$Equality.$same(comparableJsEnum, null)), comparableJsEnum)) {
+    case ComparableJsEnum.TWO: 
+     return 2;
+    case ComparableJsEnum.ONE: 
+     return 1;
+    case ComparableJsEnum.ZERO: 
+     return 0;
+   }
+  })();
+ }
+ /** @nodts */
  static m_testJsEnumAutoboxingSpecialMethods__void() {
   let stringJsEnum = StringJsEnum.ONE;
   let nullStringJsEnum = /**@type {?StringJsEnum}*/ ($Enums.unbox(null, StringJsEnum_$Overlay));

transpiler/javatests/com/google/j2cl/readable/java/jsenum/output_kt/Main.kt.txt

@@ -41,6 +41,7 @@ import kotlin.experimental.ExperimentalObjCName
 import kotlin.jvm.JvmField
 import kotlin.jvm.JvmStatic
 import kotlin.native.ObjCName
+import kotlin.run
 
 @ObjCName("J2ktJsenumMain", exact = true)
 open class Main {
@@ -97,6 +98,24 @@ open class Main {
    )
   }
 
+  @JvmStatic
+  private fun testExhaustiveJsEnumSwitchExpression() {
+   val comparableJsEnum: Main.ComparableJsEnum? = if (Main.ComparableJsEnum.ONE.getValue() == 1) Main.ComparableJsEnum.TWO else null
+   val i: Int = run {
+    when (comparableJsEnum!!) {
+     Main.ComparableJsEnum.TWO -> {
+      return@run 2
+     }
+     Main.ComparableJsEnum.ONE -> {
+      return@run 1
+     }
+     Main.ComparableJsEnum.ZERO -> {
+      return@run 0
+     }
+    }
+   }
+  }
+
   @JvmStatic
   private fun testJsEnumAutoboxingSpecialMethods() {
    val stringJsEnum: Main.StringJsEnum? = Main.StringJsEnum.ONE