GH-267 - Explicitly declared empty allowed dependencies now forbids any dependency.

The default for @ApplicationModule(allowedDependencies) is now a single element list with a dedicated token we recognize as "all dependencies allowed". This allows users to declare an empty array explicitly to disallow any outgoing dependencies for an application module. Previously, such a declaration would have allowed any dependency.

spring-modulith-integration-test/src/main/java/example/declared/first/First.java

@@ -0,0 +1,29 @@
+/*
+ * Copyright 2023 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 example.declared.first;
+
+import example.declared.second.Second;
+
+import org.springframework.stereotype.Component;
+
+/**
+ * @author Oliver Drotbohm
+ */
+@Component
+public class First {
+
+	First(Second second) {}
+}

spring-modulith-integration-test/src/main/java/example/declared/first/package-info.java

@@ -0,0 +1,3 @@
+// No dependencies allowed
+@org.springframework.modulith.ApplicationModule(allowedDependencies = {})
+package example.declared.first;

spring-modulith-integration-test/src/main/java/example/declared/fourth/Fourth.java

@@ -0,0 +1,26 @@
+/*
+ * Copyright 2023 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 example.declared.fourth;
+
+import org.springframework.stereotype.Component;
+
+/**
+ * @author Oliver Drotbohm
+ */
+@Component
+public class Fourth {
+
+}

spring-modulith-integration-test/src/main/java/example/declared/second/Second.java

@@ -0,0 +1,28 @@
+/*
+ * Copyright 2023 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 example.declared.second;
+
+import example.declared.third.Third;
+
+import org.springframework.stereotype.Component;
+
+/**
+ * @author Oliver Drotbohm
+ */
+@Component
+public class Second {
+	Second(Third third) {}
+}

spring-modulith-integration-test/src/main/java/example/declared/second/package-info.java

@@ -0,0 +1,3 @@
+// No explicit allowed dependencies -> all allowed
+@org.springframework.modulith.ApplicationModule(displayName = "Second")
+package example.declared.second;

spring-modulith-integration-test/src/main/java/example/declared/third/Third.java

@@ -0,0 +1,28 @@
+/*
+ * Copyright 2023 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 example.declared.third;
+
+import example.declared.fourth.Fourth;
+
+import org.springframework.stereotype.Component;
+
+/**
+ * @author Oliver Drotbohm
+ */
+@Component
+public class Third {
+	Third(Fourth fourth) {}
+}