fix(kotlin-spring): add parentCtorCallNeeded model template property

The new parentCtorCallNeeded property can be used by the template to
determine if there should be a constructor invocation on the parent type.

Right now its value is computed in a way that could probably use some
improvement because it is language specifically checking if the base type
is a kotlin map or not.
This might seem overly brittle, but was the only way I could differentiate
between the two different edge cases that are present in the repro spec.

This was the previous commit that changed the default behavior from one
edge case to the other (both are wrong because we can only know for sure
at generation time whether a constructor call will be necessary or not).

0bb08a7

Below is a yaml OpenAPI spec document that can be used to test/verify
the currently known edge cases (which were also mentioned in the GH
issue tracker's comments)

```yaml
openapi: 3.0.3
info:
  version: "1.0.0"
  title: ""
paths:
  /documents/v1:
    get:
      responses:
        200:
          description: lorem
          content:
            application/json:
              schema:
                type: array
                items:
                  $ref: "#/components/schemas/ParentSchema"
components:
  schemas:
    JarFiles:
      type: array
      items:
        $ref: "#/components/schemas/JarFile"
    JarFile:
      type: object
      required:
      - filename
      - contentBase64
      - hasDbMigrations
      additionalProperties: true
      properties:
        filename:
          type: string
          nullable: false
          minLength: 1
          maxLength: 255
        hasDbMigrations:
          description: Indicates whether the cordapp jar in question contains any
            embedded migrations that Cactus can/should execute between copying the
            jar into the cordapp directory and starting the node back up.
          type: boolean
          nullable: false
        contentBase64:
          type: string
          format: base64
          nullable: false
          minLength: 1
          maxLength: 1073741824

    ParentSchema:
      type: object
      properties:
        id:
          type: string
        type:
          $ref: "#/components/schemas/DiscriminatingType"
      required:
        - id
        - type
      discriminator:
        propertyName: type
        mapping:
          subtypeA: "#/components/schemas/SubtypeA"
          subtypeB: "#/components/schemas/SubtypeB"
          subtypeC: "#/components/schemas/SubtypeC"
    SubtypeA:
      type: object
      allOf:
        - $ref: '#/components/schemas/ParentSchema'
        - type: object
          properties:
            subtypeAproperty:
              type: integer
    SubtypeB:
      type: object
      allOf:
        - $ref: '#/components/schemas/ParentSchema'
        - type: object
          properties:
            subtypeBproperty:
              type: string
    SubtypeC:
      type: object
      additionalProperties: true
      allOf:
        - $ref: '#/components/schemas/ParentSchema'
        - type: object
          properties:
            subtypeAproperty:
              type: integer

    DiscriminatingType:
      type: string
      enum:
        - subtypeA
        - subtypeB
        - subtypeC
```

Fixes #8366

Signed-off-by: Peter Somogyvari <peter.metz@unarin.com>
Signed-off-by: Peter Metz <peter.metz@unarin.com>

Author: petermetz

bin/configs/kotlin-spring-issue8366-inheritance-parent-ctor-call.yaml

@@ -0,0 +1,12 @@
+generatorName: kotlin-spring
+outputDir: samples/server/petstore/kotlin-spring-issue8366-inheritance-parent-ctor-call
+library: spring-boot
+inputSpec: modules/openapi-generator/src/test/resources/3_0/kotlin/issue8366-inheritance-parent-ctor-call.yaml
+templateDir: modules/openapi-generator/src/main/resources/kotlin-spring
+additionalProperties:
+  documentationProvider: springdoc
+  annotationLibrary: swagger2
+  useSwaggerUI: "true"
+  serviceImplementation: "true"
+  reactive: "true"
+  beanValidations: "false"

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

@@ -81,6 +81,8 @@ public abstract class AbstractKotlinCodegen extends DefaultCodegen implements Co
     // ref: https://kotlinlang.org/api/latest/jvm/stdlib/kotlin.collections/-hash-map/
     protected Set<String> propertyAdditionalKeywords = new HashSet<>(Arrays.asList("entries", "keys", "size", "values"));
 
+    private final List<Pattern> PARENT_TYPES_NEEDING_CTOR_CALL = List.of(Pattern.compile("^kotlin\\.collections\\.HashMap.*"));
+
     private final Map<String, String> schemaKeyToModelNameCache = new HashMap<>();
     @Getter @Setter
     protected List<String> additionalModelTypeAnnotations = new LinkedList<>();
@@ -420,10 +422,46 @@ public ModelsMap postProcessModels(ModelsMap objs) {
                     break;
                 }
             }
+
+            final boolean isParentCtorCallNeeded = isParentCtorCallNeeded(cm);
+            cm.vendorExtensions.put("x-is-parent-ctor-call-needed", isParentCtorCallNeeded);
         }
         return postProcessModelsEnum(objs);
     }
 
+    /**
+     * Determines if a constructor call is needed for the parent type of a model
+     * and if yes, the invocation syntax `()` is added in the generated code.
+     *
+     * Important note: This is kotlin specific at the moment, but could be
+     * extended with to support detection for other languages as well.
+     *
+     * The generator used to default to issuing a supertype
+     * constructor call and then it was changed to default to not doing it.
+     * Both are wrong since there are different cases and the decision has to be
+     * made at runtime based on the parent type itself.
+     *
+     * For example if it is a HashMap (because you set
+     * additionalProperties: true for example) then it MUST HAVE a parent
+     * constructor call. If the parent type is an interface because you are
+     * using allOf with a discriminator property then the generated code for the
+     * model will have it's parent type as the interface which MUST NOT HAVE a
+     * parent constructor call.
+     *
+     * @see https://github.com/OpenAPITools/openapi-generator/issues/8366
+     *
+     * @return {boolean} `true` if the () call syntax is needed, false otherwise.
+     */
+    protected boolean isParentCtorCallNeeded(CodegenModel cm) {
+        final String parent = cm.getParent();
+
+        if (parent != null) {
+            return PARENT_TYPES_NEEDING_CTOR_CALL.stream()
+                    .anyMatch(pattern -> pattern.matcher(parent).matches());
+        }
+        return false;
+    }
+
     @Override
     public void processOpts() {
         super.processOpts();

modules/openapi-generator/src/main/resources/kotlin-spring/dataClass.mustache

@@ -18,7 +18,7 @@
 {{/hasOptional}}{{/hasRequired}}{{#optionalVars}}{{>dataClassOptVar}}{{^-last}},
 {{/-last}}{{/optionalVars}}
 ){{/discriminator}}{{! no newline
-}}{{#parent}} : {{{.}}}{{! no newline
+}}{{#parent}} : {{{.}}}{{#vendorExtensions.x-is-parent-ctor-call-needed}}(){{/vendorExtensions.x-is-parent-ctor-call-needed}}{{! no newline
     }}{{#serializableModel}}{{! no newline
       }}{{^vendorExtensions.x-kotlin-implements}}, Serializable{{/vendorExtensions.x-kotlin-implements}}{{! no newline
       }}{{#vendorExtensions.x-kotlin-implements}}, Serializable, {{! no newline

modules/openapi-generator/src/test/resources/3_0/kotlin/issue8366-inheritance-parent-ctor-call.yaml

@@ -0,0 +1,93 @@
+openapi: 3.0.3
+info:
+  version: "1.0.0"
+  title: ""
+paths:
+  /documents/v1:
+    get:
+      responses:
+        200:
+          description: lorem
+          content:
+            application/json:
+              schema:
+                type: array
+                items:
+                  $ref: "#/components/schemas/ParentSchema"
+components:
+  schemas:
+    JarFiles:
+      type: array
+      items:
+        $ref: "#/components/schemas/JarFile"
+    JarFile:
+      type: object
+      required:
+      - filename
+      - contentBase64
+      - hasDbMigrations
+      additionalProperties: true
+      properties:
+        filename:
+          type: string
+          nullable: false
+          minLength: 1
+          maxLength: 255
+        hasDbMigrations:
+          description: Indicates whether the cordapp jar in question contains any
+            embedded migrations that Cactus can/should execute between copying the
+            jar into the cordapp directory and starting the node back up.
+          type: boolean
+          nullable: false
+        contentBase64:
+          type: string
+          format: base64
+          nullable: false
+          minLength: 1
+          maxLength: 1073741824
+
+    ParentSchema:
+      type: object
+      properties:
+        id:
+          type: string
+        type:
+          $ref: "#/components/schemas/DiscriminatingType"
+      discriminator:
+        propertyName: type
+        mapping:
+          subtypeA: "#/components/schemas/SubtypeA"
+          subtypeB: "#/components/schemas/SubtypeB"
+          subtypeC: "#/components/schemas/SubtypeC"
+    SubtypeA:
+      type: object
+      allOf:
+        - $ref: '#/components/schemas/ParentSchema'
+        - type: object
+          properties:
+            subtypeAproperty:
+              type: integer
+    SubtypeB:
+      type: object
+      allOf:
+        - $ref: '#/components/schemas/ParentSchema'
+        - type: object
+          properties:
+            subtypeBproperty:
+              type: string
+    SubtypeC:
+      type: object
+      additionalProperties: true
+      allOf:
+        - $ref: '#/components/schemas/ParentSchema'
+        - type: object
+          properties:
+            subtypeAproperty:
+              type: integer
+
+    DiscriminatingType:
+      type: string
+      enum:
+        - subtypeA
+        - subtypeB
+        - subtypeC

samples/server/petstore/kotlin-spring-issue8366-inheritance-parent-ctor-call/.openapi-generator-ignore

@@ -0,0 +1,23 @@
+# OpenAPI Generator Ignore
+# Generated by openapi-generator https://github.com/openapitools/openapi-generator
+
+# Use this file to prevent files from being overwritten by the generator.
+# The patterns follow closely to .gitignore or .dockerignore.
+
+# As an example, the C# client generator defines ApiClient.cs.
+# You can make changes and tell OpenAPI Generator to ignore just this file by uncommenting the following line:
+#ApiClient.cs
+
+# You can match any string of characters against a directory, file or extension with a single asterisk (*):
+#foo/*/qux
+# The above matches foo/bar/qux and foo/baz/qux, but not foo/bar/baz/qux
+
+# You can recursively match patterns against a directory, file or extension with a double asterisk (**):
+#foo/**/qux
+# This matches foo/bar/qux, foo/baz/qux, and foo/bar/baz/qux
+
+# You can also negate patterns with an exclamation (!).
+# For example, you can ignore all files in a docs folder with the file extension .md:
+#docs/*.md
+# Then explicitly reverse the ignore rule for a single file:
+#!docs/README.md

samples/server/petstore/kotlin-spring-issue8366-inheritance-parent-ctor-call/.openapi-generator/FILES

@@ -0,0 +1,23 @@
+README.md
+build.gradle.kts
+gradle/wrapper/gradle-wrapper.jar
+gradle/wrapper/gradle-wrapper.properties
+gradlew
+gradlew.bat
+pom.xml
+settings.gradle
+src/main/kotlin/org/openapitools/Application.kt
+src/main/kotlin/org/openapitools/HomeController.kt
+src/main/kotlin/org/openapitools/api/ApiUtil.kt
+src/main/kotlin/org/openapitools/api/DocumentsApiController.kt
+src/main/kotlin/org/openapitools/api/DocumentsApiService.kt
+src/main/kotlin/org/openapitools/api/DocumentsApiServiceImpl.kt
+src/main/kotlin/org/openapitools/configuration/EnumConverterConfiguration.kt
+src/main/kotlin/org/openapitools/model/DiscriminatingType.kt
+src/main/kotlin/org/openapitools/model/JarFile.kt
+src/main/kotlin/org/openapitools/model/ParentSchema.kt
+src/main/kotlin/org/openapitools/model/SubtypeA.kt
+src/main/kotlin/org/openapitools/model/SubtypeB.kt
+src/main/kotlin/org/openapitools/model/SubtypeC.kt
+src/main/resources/application.yaml
+src/main/resources/openapi.yaml

samples/server/petstore/kotlin-spring-issue8366-inheritance-parent-ctor-call/.openapi-generator/VERSION

@@ -0,0 +1 @@
+7.16.0-SNAPSHOT

samples/server/petstore/kotlin-spring-issue8366-inheritance-parent-ctor-call/README.md

@@ -0,0 +1,21 @@
+# 
+
+This Kotlin based [Spring Boot](https://spring.io/projects/spring-boot) application has been generated using the [OpenAPI Generator](https://github.com/OpenAPITools/openapi-generator).
+
+## Getting Started
+
+This document assumes you have either maven or gradle available, either via the wrapper or otherwise. This does not come with a gradle / maven wrapper checked in.
+
+By default a [`pom.xml`](pom.xml) file will be generated. If you specified `gradleBuildFile=true` when generating this project, a `build.gradle.kts` will also be generated. Note this uses [Gradle Kotlin DSL](https://github.com/gradle/kotlin-dsl).
+
+To build the project using maven, run:
+```bash
+mvn package && java -jar target/openapi-spring-1.0.0.jar
+```
+
+To build the project using gradle, run:
+```bash
+gradle build && java -jar build/libs/openapi-spring-1.0.0.jar
+```
+
+If all builds successfully, the server should run on [http://localhost:8080/](http://localhost:8080/)

samples/server/petstore/kotlin-spring-issue8366-inheritance-parent-ctor-call/build.gradle.kts

@@ -0,0 +1,53 @@
+import org.jetbrains.kotlin.gradle.tasks.KotlinCompile
+
+buildscript {
+    repositories {
+        mavenCentral()
+    }
+    dependencies {
+        classpath("org.springframework.boot:spring-boot-gradle-plugin:2.6.7")
+    }
+}
+
+group = "org.openapitools"
+version = "1.0.0"
+
+repositories {
+    mavenCentral()
+}
+
+tasks.withType<KotlinCompile> {
+    kotlinOptions.jvmTarget = "1.8"
+}
+
+plugins {
+    val kotlinVersion = "1.9.25"
+    id("org.jetbrains.kotlin.jvm") version kotlinVersion
+    id("org.jetbrains.kotlin.plugin.jpa") version kotlinVersion
+    id("org.jetbrains.kotlin.plugin.spring") version kotlinVersion
+    id("org.springframework.boot") version "2.6.7"
+    id("io.spring.dependency-management") version "1.0.11.RELEASE"
+}
+
+dependencies {
+    val kotlinxCoroutinesVersion = "1.6.1"
+    implementation("org.jetbrains.kotlin:kotlin-stdlib-jdk8")
+    implementation("org.jetbrains.kotlin:kotlin-reflect")
+    implementation("org.springframework.boot:spring-boot-starter-webflux")
+    implementation("org.jetbrains.kotlinx:kotlinx-coroutines-core:$kotlinxCoroutinesVersion")
+    implementation("org.jetbrains.kotlinx:kotlinx-coroutines-reactor:$kotlinxCoroutinesVersion")
+    implementation("org.springdoc:springdoc-openapi-webflux-ui:1.6.8")
+
+    implementation("com.google.code.findbugs:jsr305:3.0.2")
+    implementation("com.fasterxml.jackson.dataformat:jackson-dataformat-yaml")
+    implementation("com.fasterxml.jackson.dataformat:jackson-dataformat-xml")
+    implementation("com.fasterxml.jackson.datatype:jackson-datatype-jsr310")
+    implementation("com.fasterxml.jackson.module:jackson-module-kotlin")
+    implementation("javax.validation:validation-api")
+    implementation("javax.annotation:javax.annotation-api:1.3.2")
+    testImplementation("org.jetbrains.kotlin:kotlin-test-junit5")
+    testImplementation("org.springframework.boot:spring-boot-starter-test") {
+        exclude(module = "junit")
+    }
+    testImplementation("org.jetbrains.kotlinx:kotlinx-coroutines-test:$kotlinxCoroutinesVersion")
+}