Avoid a StackOverflow and properly fail on cyclic references in CRD d…

…efinition #3651

crd-generator/api/src/main/java/io/fabric8/crd/generator/AbstractJsonSchema.java

@@ -29,19 +29,14 @@
 
 import java.util.*;
 
-import static io.sundr.model.utils.Types.BOOLEAN;
 import static io.sundr.model.utils.Types.BOOLEAN_REF;
 
-import static io.sundr.model.utils.Types.STRING;
 import static io.sundr.model.utils.Types.STRING_REF;
 
-import static io.sundr.model.utils.Types.INT;
 import static io.sundr.model.utils.Types.INT_REF;
 
-import static io.sundr.model.utils.Types.LONG;
 import static io.sundr.model.utils.Types.LONG_REF;
 
-import static io.sundr.model.utils.Types.DOUBLE;
 import static io.sundr.model.utils.Types.DOUBLE_REF;
 
 /**
@@ -117,6 +112,11 @@ public static String getSchemaTypeFor(TypeRef typeRef) {
    * @return The schema.
    */
   protected T internalFrom(TypeDef definition, String... ignore) {
+    return internalFromImpl(definition, new HashSet<>(), ignore);
+  }
+
+  private T internalFromImpl(TypeDef definition, Set<String> visited, String... ignore) {
+    visited.add(definition.getFullyQualifiedName());
     final B builder = newBuilder();
     Set<String> ignores =
       ignore.length > 0 ? new LinkedHashSet<>(Arrays.asList(ignore)) : Collections
@@ -140,7 +140,7 @@ protected T internalFrom(TypeDef definition, String... ignore) {
       if (facade.required) {
         required.add(name);
       }
-      final T schema = internalFrom(name, possiblyRenamedProperty.getTypeRef());
+      final T schema = internalFromImpl(name, possiblyRenamedProperty.getTypeRef(), visited);
       // if we got a description from the field or an accessor, use it
       final String description = facade.description;
       final T possiblyUpdatedSchema;
@@ -361,12 +361,16 @@ private String extractUpdatedNameFromJacksonPropertyIfPresent(Property property)
    * @return the structural schema associated with the specified property
    */
   public T internalFrom(String name, TypeRef typeRef) {
+    return internalFromImpl(name, typeRef, new HashSet<>());
+  }
+
+  private T internalFromImpl(String name, TypeRef typeRef, Set<String> visited) {
     // Note that ordering of the checks here is meaningful: we need to check for complex types last
     // in case some "complex" types are handled specifically
     if (typeRef.getDimensions() > 0 || io.sundr.model.utils.Collections.isCollection(typeRef)) { // Handle Collections & Arrays
       final TypeRef collectionType = TypeAs.combine(TypeAs.UNWRAP_ARRAY_OF, TypeAs.UNWRAP_COLLECTION_OF)
         .apply(typeRef);
-      final T schema = internalFrom(name, collectionType);
+      final T schema = internalFromImpl(name, collectionType, visited);
       return arrayLikeProperty(schema);
     } else if (io.sundr.model.utils.Collections.IS_MAP.apply(typeRef)) { // Handle Maps
       final TypeRef keyType = TypeAs.UNWRAP_MAP_KEY_OF.apply(typeRef);
@@ -390,7 +394,7 @@ public T internalFrom(String name, TypeRef typeRef) {
       }
       return mapLikeProperty();
     } else if (io.sundr.model.utils.Optionals.isOptional(typeRef)) { // Handle Optionals
-      return internalFrom(name, TypeAs.UNWRAP_OPTIONAL_OF.apply(typeRef));
+      return internalFromImpl(name, TypeAs.UNWRAP_OPTIONAL_OF.apply(typeRef), visited);
     } else {
       final String typeName = COMMON_MAPPINGS.get(typeRef);
       if (typeName != null) { // we have a type that we handle specifically
@@ -413,7 +417,10 @@ public T internalFrom(String name, TypeRef typeRef) {
               .toArray(JsonNode[]::new);
             return enumProperty(enumValues);
           } else {
-            return internalFrom(def);
+            if (!def.getFullyQualifiedName().startsWith("java") && visited.contains(def.getFullyQualifiedName())) {
+              throw new IllegalArgumentException("Found a cyclic reference involving " + def.getFullyQualifiedName());
+            }
+            return internalFromImpl(def, visited);
           }
 
         }

crd-generator/api/src/main/java/io/fabric8/crd/generator/v1/JsonSchema.java

@@ -22,6 +22,7 @@
 import io.sundr.model.Property;
 import io.sundr.model.TypeDef;
 import io.sundr.model.TypeRef;
+
 import java.util.List;
 
 public class JsonSchema extends AbstractJsonSchema<JSONSchemaProps, JSONSchemaPropsBuilder> {

crd-generator/api/src/main/java/io/fabric8/crd/generator/v1beta1/JsonSchema.java

@@ -22,6 +22,7 @@
 import io.sundr.model.Property;
 import io.sundr.model.TypeDef;
 import io.sundr.model.TypeRef;
+
 import java.util.List;
 
 public class JsonSchema extends AbstractJsonSchema<JSONSchemaProps, JSONSchemaPropsBuilder> {

crd-generator/api/src/test/java/io/fabric8/crd/example/cyclic/Cyclic.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 Cyclic extends CustomResource<CyclicSpec, CyclicStatus> implements Namespaced {
+
+}

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

@@ -0,0 +1,20 @@
+/**
+ * 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;
+
+public class CyclicSpec {
+  private Ref ref;
+}

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

@@ -0,0 +1,28 @@
+/**
+ * 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;
+
+public class CyclicStatus {
+  private String message;
+
+  public String getMessage() {
+    return message;
+  }
+
+  public void setMessage(String message) {
+    this.message = message;
+  }
+}

crd-generator/api/src/test/java/io/fabric8/crd/example/cyclic/Ref.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;
+
+public class Ref {
+
+  private Ref ref;
+
+}

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

@@ -18,6 +18,7 @@
 import io.fabric8.crd.example.basic.Basic;
 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.inherited.*;
 import io.fabric8.crd.example.joke.Joke;
 import io.fabric8.crd.example.joke.JokeRequest;
@@ -197,6 +198,19 @@ void shouldProperlyGenerateMultipleVersionsOfCRDs() {
     assertEquals(0, generator.generate());
   }
 
+  @Test void generatingACycleShouldFail() {
+    final CRDGenerator generator = new CRDGenerator()
+      .customResourceClasses(Cyclic.class)
+      .forCRDVersions("v1", "v1beta1")
+      .withOutput(output);
+
+    assertThrows(
+      IllegalArgumentException.class,
+      () -> generator.detailedGenerate(),
+      "Found a cyclic reference involving io.fabric8.crd.example.cyclic.Ref"
+    );
+  }
+
 
   @FunctionalInterface
   private interface CRTest {

kubernetes-tests/src/test/java/io/fabric8/crd/generator/zookeeper/v1alpha1/Zookeeper.java

@@ -24,7 +24,6 @@
 @Version(value="v1alpha1", storage=false)
 @Group("io.zookeeper")
 public class Zookeeper extends CustomResource<ZookeeperSpec, ZookeeperStatus> implements Namespaced {
-  private ZookeeperSpec spec;
-  private ZookeeperStatus status;
+
 }