Support for multiple levels of hierarchy in model objects

modules/openapi-generator/src/main/java/org/openapitools/codegen/DefaultCodegen.java

@@ -1789,7 +1789,7 @@ public CodegenModel fromModel(String name, Schema schema) {
 
             // parent model
             final String parentName = ModelUtils.getParentName(composed, allDefinitions);
-            final List<String> allParents = ModelUtils.getAllParentsName(composed, allDefinitions);
+            final List<String> allParents = ModelUtils.getAllParentsName(composed, allDefinitions, false);
             final Schema parent = StringUtils.isBlank(parentName) || allDefinitions == null ? null : allDefinitions.get(parentName);
             final boolean hasParent = StringUtils.isNotBlank(parentName);
 
@@ -1970,10 +1970,8 @@ private CodegenDiscriminator createDiscriminator(String schemaName, Schema schem
             Map<String, Schema> allDefinitions = ModelUtils.getSchemas(this.openAPI);
             allDefinitions.forEach((childName, child) -> {
                 if (child instanceof ComposedSchema && ((ComposedSchema) child).getAllOf() != null) {
-                    Set<String> parentSchemas = ((ComposedSchema) child).getAllOf().stream()
-                            .filter(s -> s.get$ref() != null)
-                            .map(s -> ModelUtils.getSimpleRef(s.get$ref()))
-                            .collect(Collectors.toSet());
+
+                    final List<String> parentSchemas = ModelUtils.getAllParentsName((ComposedSchema) child, allDefinitions, true);
                     if (parentSchemas.contains(schemaName)) {
                         discriminator.getMappedModels().add(new MappedModel(childName, toModelName(childName)));
                     }

modules/openapi-generator/src/main/java/org/openapitools/codegen/utils/ModelUtils.java

@@ -923,7 +923,7 @@ public static String getParentName(ComposedSchema composedSchema, Map<String, Sc
                     if (s == null) {
                         LOGGER.error("Failed to obtain schema from {}", parentName);
                         return "UNKNOWN_PARENT_NAME";
-                    } else if (s.getDiscriminator() != null && StringUtils.isNotEmpty(s.getDiscriminator().getPropertyName())) {
+                    } else if (hasOrInheritsDiscriminator(s, allSchemas)) {
                         // discriminator.propertyName is used
                         return parentName;
                     } else {
@@ -947,7 +947,7 @@ public static String getParentName(ComposedSchema composedSchema, Map<String, Sc
         return null;
     }
 
-    public static List<String> getAllParentsName(ComposedSchema composedSchema, Map<String, Schema> allSchemas) {
+    public static List<String> getAllParentsName(ComposedSchema composedSchema, Map<String, Schema> allSchemas, boolean includeAncestors) {
         List<Schema> interfaces = getInterfaces(composedSchema);
         List<String> names = new ArrayList<String>();
 
@@ -960,9 +960,12 @@ public static List<String> getAllParentsName(ComposedSchema composedSchema, Map<
                     if (s == null) {
                         LOGGER.error("Failed to obtain schema from {}", parentName);
                         names.add("UNKNOWN_PARENT_NAME");
-                    } else if (s.getDiscriminator() != null && StringUtils.isNotEmpty(s.getDiscriminator().getPropertyName())) {
+                    } else if (hasOrInheritsDiscriminator(s, allSchemas)) {
                         // discriminator.propertyName is used
                         names.add(parentName);
+                        if (includeAncestors && s instanceof ComposedSchema) {
+                            names.addAll(getAllParentsName((ComposedSchema) s, allSchemas, true));
+                        }
                     } else {
                         LOGGER.debug("Not a parent since discriminator.propertyName is not set {}", s.get$ref());
                         // not a parent since discriminator.propertyName is not set
@@ -976,6 +979,32 @@ public static List<String> getAllParentsName(ComposedSchema composedSchema, Map<
         return names;
     }
 
+    private static boolean hasOrInheritsDiscriminator(Schema schema, Map<String, Schema> allSchemas) {
+        if (schema.getDiscriminator() != null && StringUtils.isNotEmpty(schema.getDiscriminator().getPropertyName())) {
+            return true;
+        }
+        else if (StringUtils.isNotEmpty(schema.get$ref())) {
+            String parentName = getSimpleRef(schema.get$ref());
+            Schema s = allSchemas.get(parentName);
+            if (s != null) {
+                return hasOrInheritsDiscriminator(s, allSchemas);
+            }
+            else {
+                LOGGER.error("Failed to obtain schema from {}", parentName);
+            }
+        }
+        else if (schema instanceof ComposedSchema) {
+            final ComposedSchema composed = (ComposedSchema) schema;
+            final List<Schema> interfaces = getInterfaces(composed);
+            for (Schema i : interfaces) {
+                if (hasOrInheritsDiscriminator(i, allSchemas)) {
+                    return true;
+                }
+            }
+        }
+        return false;
+    }
+
     public static boolean isNullable(Schema schema) {
         if (schema == null) {
             return false;

modules/openapi-generator/src/test/java/org/openapitools/codegen/DefaultCodegenTest.java

@@ -452,6 +452,7 @@ public void testDiscriminator() {
         test.setPropertyName("className");
         test.getMappedModels().add(new CodegenDiscriminator.MappedModel("Dog", "Dog"));
         test.getMappedModels().add(new CodegenDiscriminator.MappedModel("Cat", "Cat"));
+        test.getMappedModels().add(new CodegenDiscriminator.MappedModel("BigCat", "BigCat"));
         Assert.assertEquals(discriminator, test);
     }
 

modules/openapi-generator/src/test/java/org/openapitools/codegen/java/jaxrs/JavaJaxrsBaseTest.java

@@ -46,6 +46,7 @@ public void generateJsonAnnotationForPolymorphism() throws IOException {
         String jsonSubType = "@JsonSubTypes({\n" +
                 "  @JsonSubTypes.Type(value = Dog.class, name = \"Dog\"),\n" +
                 "  @JsonSubTypes.Type(value = Cat.class, name = \"Cat\"),\n" +
+                "  @JsonSubTypes.Type(value = BigDog.class, name = \"BigDog\"),\n" +
                 "})";
         checkFileContains(generator, outputPath + "/src/gen/java/org/openapitools/model/Animal.java", jsonTypeInfo, jsonSubType);
     }