Write KotlinPackageFragment annotation to package$src classes

compiler/backend/src/org/jetbrains/jet/codegen/NamespaceCodegen.java

@@ -194,6 +194,8 @@ public class NamespaceCodegen extends MemberCodegen {
         );
         builder.visitSource(file.getName(), null);
 
+        writeKotlinPackageFragmentAnnotation(builder);
+
         FieldOwnerContext nameSpaceContext = CodegenContext.STATIC.intoNamespace(descriptor);
 
         FieldOwnerContext nameSpacePart = CodegenContext.STATIC.intoNamespacePart(className, descriptor);
@@ -212,6 +214,12 @@ public class NamespaceCodegen extends MemberCodegen {
         return builder;
     }
 
+    private static void writeKotlinPackageFragmentAnnotation(@NotNull ClassBuilder builder) {
+        AnnotationVisitor av = builder.newAnnotation(JvmAnnotationNames.KOTLIN_PACKAGE_FRAGMENT.getDescriptor(), true);
+        av.visit(JvmAnnotationNames.ABI_VERSION_FIELD_NAME, JvmAbi.VERSION);
+        av.visitEnd();
+    }
+
     public void generateClassOrObject(@NotNull JetClassOrObject classOrObject) {
         CodegenContext context = CodegenContext.STATIC.intoNamespace(descriptor);
         genClassOrObject(context, classOrObject);

compiler/tests/org/jetbrains/jet/codegen/KotlinPackageFragmentAnnotationTest.java

@@ -0,0 +1,58 @@
+/*
+ * Copyright 2010-2013 JetBrains s.r.o.
+ *
+ * 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 org.jetbrains.jet.codegen;
+
+import jet.KotlinPackageFragment;
+import org.jetbrains.jet.ConfigurationKind;
+import org.jetbrains.jet.lang.resolve.java.AbiVersionUtil;
+import org.jetbrains.jet.lang.resolve.java.JvmClassName;
+import org.jetbrains.jet.lang.resolve.java.PackageClassUtils;
+import org.jetbrains.jet.lang.resolve.name.FqName;
+
+public class KotlinPackageFragmentAnnotationTest extends CodegenTestCase {
+    public static final FqName NAMESPACE_NAME = new FqName("test");
+
+    @Override
+    protected void setUp() throws Exception {
+        super.setUp();
+        createEnvironmentWithMockJdkAndIdeaAnnotations(ConfigurationKind.JDK_ONLY);
+    }
+
+    public void testKotlinPackageFragmentIsWritten() throws Exception {
+        loadText("package " + NAMESPACE_NAME + "\n\nfun foo() = 42\n");
+        String facadeFileName = JvmClassName.byFqNameWithoutInnerClasses(PackageClassUtils.getPackageClassFqName(NAMESPACE_NAME)).getInternalName() + ".class";
+
+        ClassFileFactory factory = generateClassesInFile();
+        for (String fileName : factory.files()) {
+            if (!fileName.equals(facadeFileName)) {
+                // The file which is not a facade is a package fragment
+                String fqName = fileName.substring(0, fileName.length() - ".class".length()).replace('/', '.');
+                Class aClass = generateClass(fqName);
+                assertTrue("No KotlinPackageFragment annotation on a package fragment",
+                           aClass.isAnnotationPresent(KotlinPackageFragment.class));
+
+                KotlinPackageFragment annotation = (KotlinPackageFragment) aClass.getAnnotation(KotlinPackageFragment.class);
+                assertTrue("KotlinPackageFragment annotation is written with an unsupported format",
+                           AbiVersionUtil.isAbiVersionCompatible(annotation.abiVersion()));
+
+                return;
+            }
+        }
+
+        fail("No package fragment was found: " + factory.files());
+    }
+}

core/descriptor.loader.java/src/org/jetbrains/jet/lang/resolve/java/JvmAnnotationNames.java

@@ -18,6 +18,7 @@ package org.jetbrains.jet.lang.resolve.java;
 
 import jet.KotlinClass;
 import jet.KotlinPackage;
+import jet.KotlinPackageFragment;
 import jet.runtime.typeinfo.KotlinSignature;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.jet.lang.resolve.name.Name;
@@ -28,6 +29,8 @@ public final class JvmAnnotationNames {
 
     public static final JvmClassName KOTLIN_PACKAGE = JvmClassName.byClass(KotlinPackage.class);
 
+    public static final JvmClassName KOTLIN_PACKAGE_FRAGMENT = JvmClassName.byClass(KotlinPackageFragment.class);
+
     public static final String ABI_VERSION_FIELD_NAME = "abiVersion";
 
     public static final String DATA_FIELD_NAME = "data";

runtime/src/jet/KotlinPackageFragment.java

@@ -0,0 +1,25 @@
+/*
+ * Copyright 2010-2013 JetBrains s.r.o.
+ *
+ * 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 jet;
+
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+
+@Retention(RetentionPolicy.RUNTIME)
+public @interface KotlinPackageFragment {
+    int abiVersion();
+}