Kotlin Multiplatform polymorphism with custom discriminator support (#21772)

* Enable descriminator for kotlin-client multiplatform

* update template

* add sample

* update samples-kotlin-client workflow

* add missing JsonClassDiscriminator import

* fix gradlew permission

* update sample

* fix sample

* re-generate sample

Author: yshrsmz

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

@@ -33,6 +33,7 @@ jobs:
           - samples/client/petstore/kotlin-moshi-codegen
           - samples/client/petstore/kotlin-multiplatform
           - samples/client/petstore/kotlin-multiplatform-kotlinx-datetime
+          - samples/client/petstore/kotlin-multiplatform-allOf-discriminator
           - samples/client/petstore/kotlin-nonpublic
           - samples/client/petstore/kotlin-nullable
           - samples/client/petstore/kotlin-retrofit2

bin/configs/kotlin-multiplatform-allOf-discriminator.yaml

@@ -0,0 +1,8 @@
+generatorName: kotlin
+outputDir: samples/client/petstore/kotlin-multiplatform-allOf-discriminator
+library: multiplatform
+dateLibrary: kotlinx-datetime
+inputSpec: modules/openapi-generator/src/test/resources/3_0/kotlin/polymorphism.yaml
+templateDir: modules/openapi-generator/src/main/resources/kotlin-client
+additionalProperties:
+  artifactId: kotlin-multiplatform-allOf-discriminator

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

@@ -966,7 +966,7 @@ public ModelsMap postProcessModels(ModelsMap objs) {
     @Override
     public Map<String, ModelsMap> postProcessAllModels(Map<String, ModelsMap> objs) {
         objs = super.postProcessAllModels(objs);
-        if (getSerializationLibrary() == SERIALIZATION_LIBRARY_TYPE.kotlinx_serialization) {
+        if (getSerializationLibrary() == SERIALIZATION_LIBRARY_TYPE.kotlinx_serialization || getLibrary().equals(MULTIPLATFORM)) {
             // The loop removes unneeded variables so commas are handled correctly in the related templates
             for (Map.Entry<String, ModelsMap> modelsMap : objs.entrySet()) {
                 for (ModelMap mo : modelsMap.getValue().getModels()) {

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

@@ -55,6 +55,9 @@ import kotlinx.parcelize.Parcelize
 import kotlinx.serialization.*
 import kotlinx.serialization.descriptors.*
 import kotlinx.serialization.encoding.*
+{{#discriminator}}
+import kotlinx.serialization.json.JsonClassDiscriminator
+{{/discriminator}}
 {{/multiplatform}}
 {{#serializableModel}}
 import java.io.Serializable
@@ -74,7 +77,7 @@ import {{packageName}}.infrastructure.ITransformForStorage
 {{#parcelizeModels}}
 @Parcelize
 {{/parcelizeModels}}
-{{#multiplatform}}{{^discriminator}}@Serializable{{/discriminator}}{{/multiplatform}}{{#kotlinx_serialization}}{{#serializableModel}}@KSerializable{{/serializableModel}}{{^serializableModel}}@Serializable{{/serializableModel}}{{/kotlinx_serialization}}{{#moshi}}{{#moshiCodeGen}}@JsonClass(generateAdapter = true){{/moshiCodeGen}}{{/moshi}}{{#jackson}}{{#discriminator}}{{>typeInfoAnnotation}}{{/discriminator}}{{/jackson}}
+{{#multiplatform}}@Serializable{{/multiplatform}}{{#kotlinx_serialization}}{{#serializableModel}}@KSerializable{{/serializableModel}}{{^serializableModel}}@Serializable{{/serializableModel}}{{/kotlinx_serialization}}{{#moshi}}{{#moshiCodeGen}}@JsonClass(generateAdapter = true){{/moshiCodeGen}}{{/moshi}}{{#jackson}}{{#discriminator}}{{>typeInfoAnnotation}}{{/discriminator}}{{/jackson}}
 {{#isDeprecated}}
 @Deprecated(message = "This schema is deprecated.")
 {{/isDeprecated}}
@@ -91,13 +94,21 @@ import {{packageName}}.infrastructure.ITransformForStorage
 @SerialName(value = {{#lambda.doublequote}}{{{additionalProperties.discriminatorValue}}}{{/lambda.doublequote}})
 {{/additionalProperties.discriminatorValue}}
 {{/kotlinx_serialization}}
-{{#nonPublicApi}}internal {{/nonPublicApi}}{{^nonPublicApi}}{{#explicitApi}}public {{/explicitApi}}{{/nonPublicApi}}{{#discriminator}}{{#kotlinx_serialization}}sealed class{{/kotlinx_serialization}}{{^kotlinx_serialization}}interface{{/kotlinx_serialization}}{{/discriminator}}{{^discriminator}}{{#hasVars}}data {{/hasVars}}class{{/discriminator}} {{classname}}{{^discriminator}} (
+{{#multiplatform}}{{#discriminator}}
+@OptIn(ExperimentalSerializationApi::class)
+@JsonClassDiscriminator(discriminator = "{{{discriminator.propertyName}}}")
+{{/discriminator}}
+{{#additionalProperties.discriminatorValue}}
+@SerialName(value = {{#lambda.doublequote}}{{{additionalProperties.discriminatorValue}}}{{/lambda.doublequote}})
+{{/additionalProperties.discriminatorValue}}
+{{/multiplatform}}
+{{#nonPublicApi}}internal {{/nonPublicApi}}{{^nonPublicApi}}{{#explicitApi}}public {{/explicitApi}}{{/nonPublicApi}}{{#discriminator}}{{#kotlinx_serialization}}sealed class{{/kotlinx_serialization}}{{#multiplatform}}sealed class{{/multiplatform}}{{^multiplatform}}{{^kotlinx_serialization}}interface{{/kotlinx_serialization}}{{/multiplatform}}{{/discriminator}}{{^discriminator}}{{#hasVars}}data {{/hasVars}}class{{/discriminator}} {{classname}}{{^discriminator}} (
 
 {{#allVars}}
 {{#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}}{{#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}}{{#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 { }

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

@@ -15,4 +15,4 @@
     {{^isEnum}}{{^isArray}}{{^isPrimitiveType}}{{^isModel}}@Contextual {{/isModel}}{{/isPrimitiveType}}{{/isArray}}{{/isEnum}}@SerialName(value = "{{{vendorExtensions.x-base-name-literal}}}")
     {{/kotlinx_serialization}}
     {{/multiplatform}}
-    {{#multiplatform}}@SerialName(value = "{{{vendorExtensions.x-base-name-literal}}}") {{/multiplatform}}{{#kotlinx_serialization}}abstract {{/kotlinx_serialization}}{{>modelMutable}} {{{name}}}: {{#isArray}}{{#isList}}kotlin.collections.{{#modelMutable}}Mutable{{/modelMutable}}List{{/isList}}{{^isList}}kotlin.Array{{/isList}}<{{^items.isEnum}}{{^items.isPrimitiveType}}{{^items.isModel}}{{#kotlinx_serialization}}@Contextual {{/kotlinx_serialization}}{{/items.isModel}}{{/items.isPrimitiveType}}{{{items.dataType}}}{{/items.isEnum}}{{#items.isEnum}}{{classname}}.{{{nameInPascalCase}}}{{/items.isEnum}}>{{/isArray}}{{^isEnum}}{{^isArray}}{{{dataType}}}{{/isArray}}{{/isEnum}}{{#isEnum}}{{^isArray}}{{classname}}.{{{nameInPascalCase}}}{{/isArray}}{{/isEnum}}?
+    {{#multiplatform}}@SerialName(value = "{{{vendorExtensions.x-base-name-literal}}}") abstract {{/multiplatform}}{{#kotlinx_serialization}}abstract {{/kotlinx_serialization}}{{>modelMutable}} {{{name}}}: {{#isArray}}{{#isList}}kotlin.collections.{{#modelMutable}}Mutable{{/modelMutable}}List{{/isList}}{{^isList}}kotlin.Array{{/isList}}<{{^items.isEnum}}{{^items.isPrimitiveType}}{{^items.isModel}}{{#kotlinx_serialization}}@Contextual {{/kotlinx_serialization}}{{/items.isModel}}{{/items.isPrimitiveType}}{{{items.dataType}}}{{/items.isEnum}}{{#items.isEnum}}{{classname}}.{{{nameInPascalCase}}}{{/items.isEnum}}>{{/isArray}}{{^isEnum}}{{^isArray}}{{{dataType}}}{{/isArray}}{{/isEnum}}{{#isEnum}}{{^isArray}}{{classname}}.{{{nameInPascalCase}}}{{/isArray}}{{/isEnum}}?

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

@@ -15,4 +15,4 @@
     {{^isEnum}}{{^isArray}}{{^isPrimitiveType}}{{^isModel}}@Contextual {{/isModel}}{{/isPrimitiveType}}{{/isArray}}{{/isEnum}}@SerialName(value = "{{{vendorExtensions.x-base-name-literal}}}")
     {{/kotlinx_serialization}}
     {{/multiplatform}}
-    {{#multiplatform}}@SerialName(value = "{{{vendorExtensions.x-base-name-literal}}}") @Required {{/multiplatform}}{{#kotlinx_serialization}}abstract {{/kotlinx_serialization}}{{>modelMutable}} {{{name}}}: {{#isArray}}{{#isList}}kotlin.collections.{{#modelMutable}}Mutable{{/modelMutable}}List{{/isList}}{{^isList}}kotlin.Array{{/isList}}<{{^items.isEnum}}{{^items.isPrimitiveType}}{{^items.isModel}}{{#kotlinx_serialization}}@Contextual {{/kotlinx_serialization}}{{/items.isModel}}{{/items.isPrimitiveType}}{{{items.dataType}}}{{/items.isEnum}}{{#items.isEnum}}{{classname}}.{{{nameInPascalCase}}}{{/items.isEnum}}>{{/isArray}}{{^isEnum}}{{^isArray}}{{{dataType}}}{{/isArray}}{{/isEnum}}{{#isEnum}}{{^isArray}}{{classname}}.{{{nameInPascalCase}}}{{/isArray}}{{/isEnum}}{{#isNullable}}?{{/isNullable}}
+    {{#multiplatform}}@SerialName(value = "{{{vendorExtensions.x-base-name-literal}}}") @Required abstract {{/multiplatform}}{{#kotlinx_serialization}}abstract {{/kotlinx_serialization}}{{>modelMutable}} {{{name}}}: {{#isArray}}{{#isList}}kotlin.collections.{{#modelMutable}}Mutable{{/modelMutable}}List{{/isList}}{{^isList}}kotlin.Array{{/isList}}<{{^items.isEnum}}{{^items.isPrimitiveType}}{{^items.isModel}}{{#kotlinx_serialization}}@Contextual {{/kotlinx_serialization}}{{/items.isModel}}{{/items.isPrimitiveType}}{{{items.dataType}}}{{/items.isEnum}}{{#items.isEnum}}{{classname}}.{{{nameInPascalCase}}}{{/items.isEnum}}>{{/isArray}}{{^isEnum}}{{^isArray}}{{{dataType}}}{{/isArray}}{{/isEnum}}{{#isEnum}}{{^isArray}}{{classname}}.{{{nameInPascalCase}}}{{/isArray}}{{/isEnum}}{{#isNullable}}?{{/isNullable}}

samples/client/petstore/kotlin-multiplatform-allOf-discriminator/.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/client/petstore/kotlin-multiplatform-allOf-discriminator/.openapi-generator/FILES

@@ -0,0 +1,27 @@
+README.md
+build.gradle.kts
+docs/Animal.md
+docs/Bird.md
+docs/BirdApi.md
+gradle/wrapper/gradle-wrapper.jar
+gradle/wrapper/gradle-wrapper.properties
+gradlew
+gradlew.bat
+settings.gradle.kts
+src/commonMain/kotlin/org/openapitools/client/apis/BirdApi.kt
+src/commonMain/kotlin/org/openapitools/client/auth/ApiKeyAuth.kt
+src/commonMain/kotlin/org/openapitools/client/auth/Authentication.kt
+src/commonMain/kotlin/org/openapitools/client/auth/HttpBasicAuth.kt
+src/commonMain/kotlin/org/openapitools/client/auth/HttpBearerAuth.kt
+src/commonMain/kotlin/org/openapitools/client/auth/OAuth.kt
+src/commonMain/kotlin/org/openapitools/client/infrastructure/ApiAbstractions.kt
+src/commonMain/kotlin/org/openapitools/client/infrastructure/ApiClient.kt
+src/commonMain/kotlin/org/openapitools/client/infrastructure/Base64ByteArray.kt
+src/commonMain/kotlin/org/openapitools/client/infrastructure/Bytes.kt
+src/commonMain/kotlin/org/openapitools/client/infrastructure/HttpResponse.kt
+src/commonMain/kotlin/org/openapitools/client/infrastructure/OctetByteArray.kt
+src/commonMain/kotlin/org/openapitools/client/infrastructure/PartConfig.kt
+src/commonMain/kotlin/org/openapitools/client/infrastructure/RequestConfig.kt
+src/commonMain/kotlin/org/openapitools/client/infrastructure/RequestMethod.kt
+src/commonMain/kotlin/org/openapitools/client/models/Animal.kt
+src/commonMain/kotlin/org/openapitools/client/models/Bird.kt

samples/client/petstore/kotlin-multiplatform-allOf-discriminator/.openapi-generator/VERSION

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

samples/client/petstore/kotlin-multiplatform-allOf-discriminator/README.md

@@ -0,0 +1,59 @@
+# org.openapitools.client - Kotlin client library for Example
+
+An example
+
+## Overview
+This API client was generated by the [OpenAPI Generator](https://openapi-generator.tech) project.  By using the [openapi-spec](https://github.com/OAI/OpenAPI-Specification) from a remote server, you can easily generate an API client.
+
+- API version: 0.1
+- Package version: 
+- Generator version: 7.16.0-SNAPSHOT
+- Build package: org.openapitools.codegen.languages.KotlinClientCodegen
+For more information, please visit [https://example.org](https://example.org)
+
+## Requires
+
+* Kotlin 1.5.10
+
+## Build
+
+```
+./gradlew check assemble
+```
+
+This runs all tests and packages the library.
+
+## Features/Implementation Notes
+
+* Supports JSON inputs/outputs, File inputs, and Form inputs.
+* Supports collection formats for query parameters: csv, tsv, ssv, pipes.
+* Some Kotlin and Java types are fully qualified to avoid conflicts with types defined in OpenAPI definitions.
+
+
+<a id="documentation-for-api-endpoints"></a>
+## Documentation for API Endpoints
+
+All URIs are relative to *http://example.org*
+
+| Class | Method | HTTP request | Description |
+| ------------ | ------------- | ------------- | ------------- |
+| *BirdApi* | [**getBird**](docs/BirdApi.md#getbird) | **GET** /v1/bird/{id} |  |
+
+
+<a id="documentation-for-models"></a>
+## Documentation for Models
+
+ - [org.openapitools.client.models.Animal](docs/Animal.md)
+ - [org.openapitools.client.models.Bird](docs/Bird.md)
+
+
+<a id="documentation-for-authorization"></a>
+## Documentation for Authorization
+
+Endpoints do not require authorization.
+
+
+
+## Author
+
+[email protected]