Add support for x-kotlin-implements vendor extension to the kotlin client generator

Author: Mattias-Sehlstedt

.github/workflows/samples-kotlin-client.yaml

@@ -71,6 +71,7 @@ jobs:
           - samples/client/others/kotlin-jvm-okhttp-path-comments
           - samples/client/others/kotlin-integer-enum
           - samples/client/petstore/kotlin-allOf-discriminator-kotlinx-serialization
+          - samples/client/others/kotlin-oneOf-discriminator
     steps:
       - uses: actions/checkout@v5
       - uses: actions/setup-java@v5

bin/configs/kotlin-oneOf-discriminator.yaml

@@ -0,0 +1,11 @@
+generatorName: kotlin
+library: jvm-spring-restclient
+outputDir: samples/client/others/kotlin-oneOf-discriminator
+inputSpec: modules/openapi-generator/src/test/resources/3_0/kotlin/oneOf-with-discriminator-mapping.yaml
+templateDir: modules/openapi-generator/src/main/resources/kotlin-client
+additionalProperties:
+  artifactId: kotlin-oneOf-discriminator
+  serializableModel: "false"
+  dateLibrary: java8
+  useSpringBoot3: true
+  serializationLibrary: jackson

docs/generators/kotlin.md

@@ -59,6 +59,8 @@ These options may be applied as additional-properties (cli) or configOptions (pl
 
 | Extension name | Description | Applicable for | Default value |
 | -------------- | ----------- | -------------- | ------------- |
+|x-kotlin-implements|Ability to specify interfaces that model must implement|MODEL|empty array
+|x-kotlin-implements-fields|Specify attributes that are implemented by the interface(s) added via `x-kotlin-implements`|MODEL|empty array
 |x-class-extra-annotation|List of custom annotations to be added to model|MODEL|null
 |x-field-extra-annotation|List of custom annotations to be added to property|FIELD, OPERATION_PARAMETER|null
 

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

@@ -26,8 +26,7 @@ public enum VendorExtension {
     X_OPERATION_EXTRA_ANNOTATION("x-operation-extra-annotation", ExtensionLevel.OPERATION, "List of custom annotations to be added to operation", null),
     X_VERSION_PARAM("x-version-param", ExtensionLevel.OPERATION_PARAMETER, "Marker property that tells that this parameter would be used for endpoint versioning. Applicable for headers & query params. true/false", null),
     X_PATTERN_MESSAGE("x-pattern-message", Arrays.asList(ExtensionLevel.FIELD, ExtensionLevel.OPERATION_PARAMETER), "Add this property whenever you need to customize the invalidation error message for the regex pattern of a variable", null),
-    X_ZERO_BASED_ENUM("x-zero-based-enum", ExtensionLevel.MODEL, "When used on an enum, the index will not be generated and the default numbering will be used, zero-based", "false"),
-    ;
+    X_ZERO_BASED_ENUM("x-zero-based-enum", ExtensionLevel.MODEL, "When used on an enum, the index will not be generated and the default numbering will be used, zero-based", "false");
 
     private final String name;
     private final List<ExtensionLevel> levels;

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

@@ -828,23 +828,13 @@ protected boolean isReservedWord(String word) {
     protected boolean needToImport(String type) {
         // provides extra protection against improperly trying to import language primitives and java types
         return !type.startsWith("kotlin.") && !type.startsWith("java.") &&
-                !defaultIncludes.contains(type) && !languageSpecificPrimitives.contains(type) &&
-                !type.contains(".");
+               !defaultIncludes.contains(type) && !languageSpecificPrimitives.contains(type) &&
+               !type.contains(".");
     }
 
     @Override
     public CodegenModel fromModel(String name, Schema schema) {
         CodegenModel m = super.fromModel(name, schema);
-        List<String> implementedInterfacesClasses = (List<String>) m.getVendorExtensions().getOrDefault(VendorExtension.X_KOTLIN_IMPLEMENTS.getName(), List.of());
-        List<String> implementedInterfacesFields = Optional.ofNullable((List<String>) m.getVendorExtensions().get(VendorExtension.X_KOTLIN_IMPLEMENTS_FIELDS.getName()))
-                .map(xKotlinImplementsFields -> {
-                    if (implementedInterfacesClasses.isEmpty() && !xKotlinImplementsFields.isEmpty()) {
-                        LOGGER.warn("Annotating {} with {} without {} is not supported. {} will be ignored.",
-                                name, VendorExtension.X_KOTLIN_IMPLEMENTS_FIELDS.getName(), VendorExtension.X_KOTLIN_IMPLEMENTS.getName(),
-                                VendorExtension.X_KOTLIN_IMPLEMENTS_FIELDS.getName());
-                    }
-                    return xKotlinImplementsFields;
-                }).orElse(List.of());
         m.optionalVars = m.optionalVars.stream().distinct().collect(Collectors.toList());
         // Update allVars/requiredVars/optionalVars with isInherited
         // Each of these lists contains elements that are similar, but they are all cloned
@@ -860,11 +850,9 @@ public CodegenModel fromModel(String name, Schema schema) {
         // Update any other vars (requiredVars, optionalVars)
         Stream.of(m.requiredVars, m.optionalVars)
                 .flatMap(List::stream)
-                .filter(p -> allVarsMap.containsKey(p.baseName)
-                             || implementedInterfacesFields.contains(p.baseName)
-                )
+                .filter(p -> allVarsMap.containsKey(p.baseName))
                 .forEach(p -> p.isInherited = true);
-        return m;
+        return addIsInheritedBasedOnImplementsVendorExtension(name, m);
     }
 
     @Override
@@ -1172,4 +1160,44 @@ protected void doDataTypeAssignment(final String returnType, DataTypeAssigner da
             }
         }
     }
+
+    /**
+     * Uses the x-kotlin-implements and the x-kotlin-implements-fields vendor extensions to set the isInherited CodegenProperty field.
+     * Will log a warning if an invalid vendor extension combination is used.
+     * @param name The name
+     * @param codegenModel The codegenModel
+     * @return The modified CodegenModel where isInherited has been added to the var CodegenProperty
+     */
+    private CodegenModel addIsInheritedBasedOnImplementsVendorExtension(String name, CodegenModel codegenModel) {
+        String warningMessage = "Annotating {} with {} without {} is not supported. {} will be ignored.";
+        String kotlinImplements = VendorExtension.X_KOTLIN_IMPLEMENTS.getName();
+        String kotlinImplementsFields = VendorExtension.X_KOTLIN_IMPLEMENTS_FIELDS.getName();
+        Map<String, Object> vendorExtensions = codegenModel.getVendorExtensions();
+        List<String> implementedInterfacesClasses = (List<String>) vendorExtensions.getOrDefault(kotlinImplements, List.of());
+        List<String> implementedInterfacesFields = Optional.ofNullable((List<String>) vendorExtensions.get(kotlinImplementsFields))
+                .map(xKotlinImplementsFields -> {
+                    if (implementedInterfacesClasses.isEmpty() && !xKotlinImplementsFields.isEmpty()) {
+                        LOGGER.warn(warningMessage, name,
+                                kotlinImplementsFields,
+                                kotlinImplements,
+                                kotlinImplementsFields
+                        );
+                    }
+                    return xKotlinImplementsFields;
+                })
+                .orElse(List.of());
+        codegenModel.optionalVars.stream()
+                .filter(p -> implementedInterfacesFields.contains(p.baseName))
+                .forEach(p -> p.isInherited = true);
+        codegenModel.requiredVars.stream()
+                .filter(p -> implementedInterfacesFields.contains(p.baseName))
+                .forEach(p -> p.isInherited = true);
+        codegenModel.allVars.stream()
+                .filter(p -> implementedInterfacesFields.contains(p.baseName))
+                .forEach(p -> p.isInherited = true);
+        codegenModel.vars.stream()
+                .filter(p -> implementedInterfacesFields.contains(p.baseName))
+                .forEach(p -> p.isInherited = true);
+        return codegenModel;
+    }
 }

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

@@ -1128,6 +1128,8 @@ public void postProcess() {
     @Override
     public List<VendorExtension> getSupportedVendorExtensions() {
         var extensions = super.getSupportedVendorExtensions();
+        extensions.add(VendorExtension.X_KOTLIN_IMPLEMENTS);
+        extensions.add(VendorExtension.X_KOTLIN_IMPLEMENTS_FIELDS);
         extensions.add(VendorExtension.X_CLASS_EXTRA_ANNOTATION);
         extensions.add(VendorExtension.X_FIELD_EXTRA_ANNOTATION);
         return extensions;

modules/openapi-generator/src/main/resources/kotlin-client/data_class.mustache

@@ -108,7 +108,7 @@ import {{packageName}}.infrastructure.ITransformForStorage
 {{#required}}{{>data_class_req_var}}{{/required}}{{^required}}{{>data_class_opt_var}}{{/required}}{{^-last}},{{/-last}}
 
 {{/allVars}}
-){{/discriminator}}{{#parent}}{{^serializableModel}}{{^parcelizeModels}} : {{{parent}}}{{#isMap}}(){{/isMap}}{{#kotlinx_serialization}}(){{/kotlinx_serialization}}{{#multiplatform}}(){{/multiplatform}}{{#isArray}}(){{/isArray}}{{/parcelizeModels}}{{/serializableModel}}{{/parent}}{{#parent}}{{#serializableModel}}{{^parcelizeModels}} : {{{parent}}}{{#isMap}}(){{/isMap}}{{#isArray}}(){{/isArray}}, Serializable{{/parcelizeModels}}{{/serializableModel}}{{/parent}}{{#parent}}{{^serializableModel}}{{#parcelizeModels}} : {{{parent}}}{{#isMap}}(){{/isMap}}{{#isArray}}(){{/isArray}}, Parcelable{{/parcelizeModels}}{{/serializableModel}}{{/parent}}{{#parent}}{{#serializableModel}}{{#parcelizeModels}} : {{{parent}}}{{#isMap}}(){{/isMap}}{{#isArray}}(){{/isArray}}, Serializable, Parcelable{{/parcelizeModels}}{{/serializableModel}}{{/parent}}{{^parent}}{{#serializableModel}}{{^parcelizeModels}} : Serializable{{/parcelizeModels}}{{/serializableModel}}{{/parent}}{{^parent}}{{^serializableModel}}{{#parcelizeModels}} : Parcelable{{/parcelizeModels}}{{/serializableModel}}{{/parent}}{{^parent}}{{#serializableModel}}{{#parcelizeModels}} : Serializable, Parcelable{{/parcelizeModels}}{{/serializableModel}}{{/parent}}{{#generateRoomModels}}{{#parent}}, {{/parent}}{{^discriminator}}{{^parent}}:{{/parent}} ITransformForStorage<{{classname}}RoomModel>{{/discriminator}}{{/generateRoomModels}}{{#vendorExtensions.x-has-data-class-body}} {
+){{/discriminator}}{{#vendorExtensions.x-kotlin-implements}} : {{{.}}}{{^-last}}, {{/-last}}{{/vendorExtensions.x-kotlin-implements}}{{#parent}}{{^serializableModel}}{{^parcelizeModels}} : {{{parent}}}{{#isMap}}(){{/isMap}}{{#kotlinx_serialization}}(){{/kotlinx_serialization}}{{#multiplatform}}(){{/multiplatform}}{{#isArray}}(){{/isArray}}{{/parcelizeModels}}{{/serializableModel}}{{/parent}}{{#parent}}{{#serializableModel}}{{^parcelizeModels}} : {{{parent}}}{{#isMap}}(){{/isMap}}{{#isArray}}(){{/isArray}}, Serializable{{/parcelizeModels}}{{/serializableModel}}{{/parent}}{{#parent}}{{^serializableModel}}{{#parcelizeModels}} : {{{parent}}}{{#isMap}}(){{/isMap}}{{#isArray}}(){{/isArray}}, Parcelable{{/parcelizeModels}}{{/serializableModel}}{{/parent}}{{#parent}}{{#serializableModel}}{{#parcelizeModels}} : {{{parent}}}{{#isMap}}(){{/isMap}}{{#isArray}}(){{/isArray}}, Serializable, Parcelable{{/parcelizeModels}}{{/serializableModel}}{{/parent}}{{^parent}}{{#serializableModel}}{{^parcelizeModels}} : Serializable{{/parcelizeModels}}{{/serializableModel}}{{/parent}}{{^parent}}{{^serializableModel}}{{#parcelizeModels}} : Parcelable{{/parcelizeModels}}{{/serializableModel}}{{/parent}}{{^parent}}{{#serializableModel}}{{#parcelizeModels}} : Serializable, Parcelable{{/parcelizeModels}}{{/serializableModel}}{{/parent}}{{#generateRoomModels}}{{#parent}}, {{/parent}}{{^discriminator}}{{^parent}}:{{/parent}} ITransformForStorage<{{classname}}RoomModel>{{/discriminator}}{{/generateRoomModels}}{{#vendorExtensions.x-has-data-class-body}} {
 {{/vendorExtensions.x-has-data-class-body}}
 {{#generateRoomModels}}
     companion object { }