GH-284 - Support for open application modules.

Application modules can now be declared as open, which causes internal components being exposed for access by other modules.

spring-modulith-integration-test/src/main/java/com/acme/myproject/open/internal/Internal.java

@@ -0,0 +1,29 @@
+/*
+ * Copyright 2024 the original author or authors.
+ *
+ * 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
+ *
+ *      https://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 com.acme.myproject.open.internal;
+
+import org.springframework.stereotype.Component;
+
+import com.acme.myproject.openclient.ClientToInternal;
+
+/**
+ * @author Oliver Drotbohm
+ */
+@Component
+public class Internal {
+
+	ClientToInternal clientToInternal;
+}

spring-modulith-integration-test/src/main/java/com/acme/myproject/open/package-info.java

@@ -0,0 +1,5 @@
+@ApplicationModule(type = Type.OPEN)
+package com.acme.myproject.open;
+
+import org.springframework.modulith.ApplicationModule;
+import org.springframework.modulith.ApplicationModule.Type;

spring-modulith-integration-test/src/main/java/com/acme/myproject/openclient/ClientToInternal.java

@@ -0,0 +1,26 @@
+/*
+ * Copyright 2024 the original author or authors.
+ *
+ * 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
+ *
+ *      https://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 com.acme.myproject.openclient;
+
+import com.acme.myproject.open.internal.Internal;
+
+/**
+ * @author Oliver Drotbohm
+ */
+public class ClientToInternal {
+
+	Internal internal;
+}

spring-modulith-integration-test/src/main/java/com/acme/myproject/opendisallowedclient/DisallowedClientOfInternal.java

@@ -0,0 +1,25 @@
+/*
+ * Copyright 2024 the original author or authors.
+ *
+ * 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
+ *
+ *      https://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 com.acme.myproject.opendisallowedclient;
+
+import com.acme.myproject.open.internal.Internal;
+
+/**
+ * @author Oliver Drotbohm
+ */
+public class DisallowedClientOfInternal {
+	Internal internal;
+}

spring-modulith-integration-test/src/main/java/com/acme/myproject/opendisallowedclient/package-info.java

@@ -0,0 +1,2 @@
+@org.springframework.modulith.ApplicationModule(allowedDependencies = "moduleA")
+package com.acme.myproject.opendisallowedclient;

spring-modulith-integration-test/src/test/java/com/acme/myproject/ModulithTest.java

@@ -61,7 +61,7 @@ class ModulithTest {
 		assertThatExceptionOfType(Violations.class).isThrownBy(() -> {
 
 			ApplicationModules
-					.of(Application.class, DEFAULT_EXCLUSIONS.or(Filters.withoutModule("invalid")))
+					.of(Application.class, DEFAULT_EXCLUSIONS.or(Filters.withoutModules("invalid", "opendisallowedclient")))
 					.verify();
 
 		}).satisfies(it -> {

spring-modulith-integration-test/src/test/java/org/springframework/modulith/core/ApplicationModulesIntegrationTest.java

@@ -211,6 +211,29 @@ class ApplicationModulesIntegrationTest {
 		});
 	}
 
+	@Test // GH-284
+	void detectsOpenModule() {
+
+		assertThat(modules.getModuleByName("open")).hasValueSatisfying(it -> {
+			assertThat(it.isOpen()).isTrue();
+		});
+
+		var detectViolations = modules.detectViolations().getMessages();
+
+		assertThat(detectViolations)
+				.isNotEmpty()
+
+				// No invalid references to internals from unrestricted module
+				.noneMatch(it -> it.matches("Module 'openclient' depends on non-exposed type .* within module 'open'"))
+
+				// Invalid reference to internals from restricted module
+				.anyMatch(it -> it.contains("Module 'opendisallowedclient' depends on module 'open'"))
+
+				// No cycle detection
+				.anyMatch(it -> it.contains("Cycle detected: Slice cycleA"))
+				.noneMatch(it -> it.contains("Cycle detected: Slice open"));
+	}
+
 	private static void verifyNamedInterfaces(NamedInterfaces interfaces, String name, Class<?>... types) {
 
 		Stream.of(types).forEach(type -> {

spring-modulith-integration-test/src/test/resources/application.properties

@@ -0,0 +1 @@
+spring.main.banner-mode=off

spring-modulith-integration-test/src/test/resources/logback.xml

@@ -9,7 +9,7 @@
 
 	<logger name="org.springframework.modulith" level="error" />
 
-	<root level="error">
+	<root level="off">
 		<appender-ref ref="console" />
 	</root>