Fix StackOverflow on cyclic references involving collections.

Fixes #4510

CHANGELOG.md

@@ -5,6 +5,7 @@
 #### Bugs
 * Fix #4159: ensure the token refresh obeys how the Config was created
 * Fix #4491: added a more explicit shutdown exception for okhttp
+* Fix #4510: Fix StackOverflow on cyclic references involving collections.
 * Fix #4534: Java Generator CLI default handling of skipGeneratedAnnotations
 * Fix #4535: The shell command string will now have single quotes sanitized
 * Fix #4543: (Java Generator) additionalProperties JsonAny setter method generated as setAdditionalProperty

crd-generator/api/src/main/java/io/fabric8/crd/generator/visitor/ClassDependenciesVisitor.java

@@ -33,7 +33,7 @@ public class ClassDependenciesVisitor extends TypedVisitor<TypeDefBuilder> {
   private static final Map<String, Set<String>> traversedClasses = new HashMap<>();
   private static final Map<String, Set<String>> crdNameToCrClass = new HashMap<>();
   private final Set<String> classesForCR;
-  private final Set<String> processed = new HashSet<>();
+  private final Set<ClassRef> processed = new HashSet<>();
 
   public ClassDependenciesVisitor(String crClassName, String crdName) {
     // need to record all classes associated with the different versions of the CR (not the CRD spec)
@@ -49,7 +49,7 @@ public void visit(TypeDefBuilder builder) {
     // note that we cannot simply check the traversed class set to know if a class has been processed because classes
     // are usually added to the traversed set before they're looked at in depth
     final String className = type.getFullyQualifiedName();
-    if (ignore(className) || processed.contains(className)) {
+    if (ignore(className)) {
       return;
     }
 
@@ -74,19 +74,21 @@ public void visit(TypeDefBuilder builder) {
 
     // add classes from extends list
     type.getExtendsList().forEach(this::processTypeRef);
-
-    // add class to the processed classes
-    processed.add(className);
   }
 
   private boolean ignore(String className) {
-    return (className.startsWith("java.") && !className.startsWith("java.util.")) || className.startsWith("com.fasterxml.jackson") || className.startsWith("jdk.");
+    return (className.startsWith("java.") && !className.startsWith("java.util."))
+        || className.startsWith("com.fasterxml.jackson") || className.startsWith("jdk.");
   }
 
   private void processTypeRef(TypeRef t) {
     if (t instanceof ClassRef) {
       ClassRef classRef = (ClassRef) t;
-      visit(new TypeDefBuilder(Types.typeDefFrom(classRef)));
+      // only process the class reference if we haven't already
+      // note that the references are stored in the set including type arguments, so List<A> and List<B> are not the same
+      if (processed.add(classRef)) {
+        visit(new TypeDefBuilder(Types.typeDefFrom(classRef)));
+      }
     }
   }
 
@@ -101,7 +103,7 @@ public static Set<String> getDependentClasses(String crClassName) {
   public static Set<String> getDependentClassesFromCRDName(String crdName) {
     // retrieve all dependent classes that might affect any of the CR versions
     return crdNameToCrClass.get(crdName).stream()
-      .flatMap(crClassName -> traversedClasses.get(crClassName).stream())
-      .collect(Collectors.toSet());
+        .flatMap(crClassName -> traversedClasses.get(crClassName).stream())
+        .collect(Collectors.toSet());
   }
 }

crd-generator/api/src/test/java/io/fabric8/crd/example/cyclic/CyclicList.java

@@ -0,0 +1,27 @@
+/**
+ * Copyright (C) 2015 Red Hat, 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 io.fabric8.crd.example.cyclic;
+
+import io.fabric8.kubernetes.api.model.Namespaced;
+import io.fabric8.kubernetes.client.CustomResource;
+import io.fabric8.kubernetes.model.annotation.Group;
+import io.fabric8.kubernetes.model.annotation.Version;
+
+@Group("sample.fabric8.io")
+@Version("v1alpha1")
+public class CyclicList extends CustomResource<CyclicListSpec, CyclicStatus> implements Namespaced {
+
+}

crd-generator/api/src/test/java/io/fabric8/crd/example/cyclic/CyclicListSpec.java

@@ -0,0 +1,22 @@
+/**
+ * Copyright (C) 2015 Red Hat, 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 io.fabric8.crd.example.cyclic;
+
+import java.util.List;
+
+public class CyclicListSpec {
+  private List<RefList> ref;
+}

crd-generator/api/src/test/java/io/fabric8/crd/example/cyclic/RefList.java

@@ -0,0 +1,24 @@
+/**
+ * Copyright (C) 2015 Red Hat, 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 io.fabric8.crd.example.cyclic;
+
+import java.util.List;
+
+public class RefList {
+
+  private List<RefList> ref;
+
+}

crd-generator/api/src/test/java/io/fabric8/crd/generator/CRDGeneratorTest.java

@@ -19,6 +19,7 @@
 import io.fabric8.crd.example.basic.BasicSpec;
 import io.fabric8.crd.example.basic.BasicStatus;
 import io.fabric8.crd.example.cyclic.Cyclic;
+import io.fabric8.crd.example.cyclic.CyclicList;
 import io.fabric8.crd.example.inherited.*;
 import io.fabric8.crd.example.joke.Joke;
 import io.fabric8.crd.example.joke.JokeRequest;
@@ -216,6 +217,19 @@ void generatingACycleShouldFail() {
         "An IllegalArgument Exception hasn't been thrown when generating a CRD with cyclic references");
   }
 
+  @Test
+  void generatingACycleInListShouldFail() {
+    final CRDGenerator generator = new CRDGenerator()
+        .customResourceClasses(CyclicList.class)
+        .forCRDVersions("v1", "v1beta1")
+        .withOutput(output);
+
+    assertThrows(
+        IllegalArgumentException.class,
+        () -> generator.detailedGenerate(),
+        "An IllegalArgument Exception hasn't been thrown when generating a CRD with cyclic references");
+  }
+
   @Test
   void notGeneratingACycleShouldSucceed() {
     final CRDGenerator generator = new CRDGenerator()