better handling of const value

* Autosets the parameters with the only value specified as enum if the parameter is also marked as required

* Autosets the parameters with the only value specified as enum if the parameter is also marked as required

* Autosets the parameters with the only value specified as enum if the parameter is also marked as required for Java default client.

* Autosets the parameters with the only value specified as enum if the parameter is also marked as required for Java default client.

* Autosets the parameters with the only value specified as enum if the parameter is also marked as required for Java default client.

* Autosets the parameters with the only value specified as enum if the parameter is also marked as required for Java default client.

.java-version

@@ -1 +1 @@
-1.8
+11

bin/configs/python-flask.yaml

@@ -1,4 +1,4 @@
 generatorName: python-flask
 outputDir: samples/server/petstore/python-flask
-inputSpec: modules/openapi-generator/src/test/resources/2_0/petstore.yaml
+inputSpec: modules/openapi-generator/src/test/resources/2_0/python-flask/petstore.yaml
 templateDir: modules/openapi-generator/src/main/resources/python-flask

docs/generators/groovy.md

@@ -25,6 +25,7 @@ These options may be applied as additional-properties (cli) or configOptions (pl
 |apiPackage|package for generated api classes| |org.openapitools.api|
 |artifactId|artifactId in generated pom.xml. This also becomes part of the generated library's filename| |openapi-groovy|
 |artifactVersion|artifact version in generated pom.xml. This also becomes part of the generated library's filename| |1.0.0|
+|autosetConstants|Automatically set Required Params having a Single enum value i.e. Constants in generated code| |false|
 |bigDecimalAsString|Treat BigDecimal values as Strings to avoid precision loss.| |false|
 |booleanGetterPrefix|Set booleanGetterPrefix| |get|
 |camelCaseDollarSign|Fix camelCase when starting with $ sign. when true : $Value when false : $value| |false|

docs/generators/java-camel.md

@@ -30,6 +30,7 @@ These options may be applied as additional-properties (cli) or configOptions (pl
 |artifactUrl|artifact URL in generated pom.xml| |https://github.com/openapitools/openapi-generator|
 |artifactVersion|artifact version in generated pom.xml. This also becomes part of the generated library's filename| |1.0.0|
 |async|use async Callable controllers| |false|
+|autosetConstants|Automatically set Required Params having a Single enum value i.e. Constants in generated code| |false|
 |basePackage|base package (invokerPackage) for generated code| |org.openapitools|
 |bigDecimalAsString|Treat BigDecimal values as Strings to avoid precision loss.| |false|
 |booleanGetterPrefix|Set booleanGetterPrefix| |get|

docs/generators/java-helidon-client.md

@@ -27,6 +27,7 @@ These options may be applied as additional-properties (cli) or configOptions (pl
 |artifactId|artifactId in generated pom.xml. This also becomes part of the generated library's filename| |openapi-java-client|
 |artifactUrl|artifact URL in generated pom.xml| |https://github.com/openapitools/openapi-generator|
 |artifactVersion|artifact version in generated pom.xml. This also becomes part of the generated library's filename| |1.0.0|
+|autosetConstants|Automatically set Required Params having a Single enum value i.e. Constants in generated code| |false|
 |bigDecimalAsString|Treat BigDecimal values as Strings to avoid precision loss.| |false|
 |booleanGetterPrefix|Set booleanGetterPrefix| |get|
 |camelCaseDollarSign|Fix camelCase when starting with $ sign. when true : $Value when false : $value| |false|

docs/generators/java-helidon-server.md

@@ -27,6 +27,7 @@ These options may be applied as additional-properties (cli) or configOptions (pl
 |artifactId|artifactId in generated pom.xml. This also becomes part of the generated library's filename| |openapi-java-server|
 |artifactUrl|artifact URL in generated pom.xml| |https://github.com/openapitools/openapi-generator|
 |artifactVersion|artifact version in generated pom.xml. This also becomes part of the generated library's filename| |1.0.0|
+|autosetConstants|Automatically set Required Params having a Single enum value i.e. Constants in generated code| |false|
 |bigDecimalAsString|Treat BigDecimal values as Strings to avoid precision loss.| |false|
 |booleanGetterPrefix|Set booleanGetterPrefix| |get|
 |camelCaseDollarSign|Fix camelCase when starting with $ sign. when true : $Value when false : $value| |false|

docs/generators/java-inflector.md

@@ -27,6 +27,7 @@ These options may be applied as additional-properties (cli) or configOptions (pl
 |artifactId|artifactId in generated pom.xml. This also becomes part of the generated library's filename| |openapi-inflector-server|
 |artifactUrl|artifact URL in generated pom.xml| |https://github.com/openapitools/openapi-generator|
 |artifactVersion|artifact version in generated pom.xml. This also becomes part of the generated library's filename| |1.0.0|
+|autosetConstants|Automatically set Required Params having a Single enum value i.e. Constants in generated code| |false|
 |bigDecimalAsString|Treat BigDecimal values as Strings to avoid precision loss.| |false|
 |booleanGetterPrefix|Set booleanGetterPrefix| |get|
 |camelCaseDollarSign|Fix camelCase when starting with $ sign. when true : $Value when false : $value| |false|

docs/generators/java-micronaut-client.md

@@ -30,6 +30,7 @@ These options may be applied as additional-properties (cli) or configOptions (pl
 |artifactUrl|artifact URL in generated pom.xml| |https://github.com/openapitools/openapi-generator|
 |artifactVersion|artifact version in generated pom.xml. This also becomes part of the generated library's filename| |1.0.0|
 |authorizationFilterPattern|Configure the authorization filter pattern for the client. Generally defined when generating clients from multiple specification files| |null|
+|autosetConstants|Automatically set Required Params having a Single enum value i.e. Constants in generated code| |false|
 |basePathSeparator|Configure the separator to use between the application name and base path when referencing the property| |-|
 |bigDecimalAsString|Treat BigDecimal values as Strings to avoid precision loss.| |false|
 |booleanGetterPrefix|Set booleanGetterPrefix| |get|

docs/generators/java-micronaut-server.md

@@ -27,6 +27,7 @@ These options may be applied as additional-properties (cli) or configOptions (pl
 |artifactId|artifactId in generated pom.xml. This also becomes part of the generated library's filename| |openapi-micronaut|
 |artifactUrl|artifact URL in generated pom.xml| |https://github.com/openapitools/openapi-generator|
 |artifactVersion|artifact version in generated pom.xml. This also becomes part of the generated library's filename| |1.0.0|
+|autosetConstants|Automatically set Required Params having a Single enum value i.e. Constants in generated code| |false|
 |bigDecimalAsString|Treat BigDecimal values as Strings to avoid precision loss.| |false|
 |booleanGetterPrefix|Set booleanGetterPrefix| |get|
 |build|Specify for which build tool to generate files|<dl><dt>**gradle**</dt><dd>Gradle configuration is generated for the project</dd><dt>**all**</dt><dd>Both Gradle and Maven configurations are generated</dd><dt>**maven**</dt><dd>Maven configuration is generated for the project</dd></dl>|all|

docs/generators/java-msf4j.md

@@ -27,6 +27,7 @@ These options may be applied as additional-properties (cli) or configOptions (pl
 |artifactId|artifactId in generated pom.xml. This also becomes part of the generated library's filename| |openapi-jaxrs-server|
 |artifactUrl|artifact URL in generated pom.xml| |https://github.com/openapitools/openapi-generator|
 |artifactVersion|artifact version in generated pom.xml. This also becomes part of the generated library's filename| |1.0.0|
+|autosetConstants|Automatically set Required Params having a Single enum value i.e. Constants in generated code| |false|
 |bigDecimalAsString|Treat BigDecimal values as Strings to avoid precision loss.| |false|
 |booleanGetterPrefix|Set booleanGetterPrefix| |get|
 |camelCaseDollarSign|Fix camelCase when starting with $ sign. when true : $Value when false : $value| |false|

docs/generators/java-pkmst.md

@@ -27,6 +27,7 @@ These options may be applied as additional-properties (cli) or configOptions (pl
 |artifactId|artifactId in generated pom.xml. This also becomes part of the generated library's filename| |pkmst-microservice|
 |artifactUrl|artifact URL in generated pom.xml| |https://github.com/openapitools/openapi-generator|
 |artifactVersion|artifact version in generated pom.xml. This also becomes part of the generated library's filename| |1.0.0|
+|autosetConstants|Automatically set Required Params having a Single enum value i.e. Constants in generated code| |false|
 |basePackage|base package for java source code| |null|
 |bigDecimalAsString|Treat BigDecimal values as Strings to avoid precision loss.| |false|
 |booleanGetterPrefix|Set booleanGetterPrefix| |get|

docs/generators/java-play-framework.md

@@ -27,6 +27,7 @@ These options may be applied as additional-properties (cli) or configOptions (pl
 |artifactId|artifactId in generated pom.xml. This also becomes part of the generated library's filename| |openapi-java-playframework|
 |artifactUrl|artifact URL in generated pom.xml| |https://github.com/openapitools/openapi-generator|
 |artifactVersion|artifact version in generated pom.xml. This also becomes part of the generated library's filename| |1.0.0|
+|autosetConstants|Automatically set Required Params having a Single enum value i.e. Constants in generated code| |false|
 |basePackage|base package for generated code| |org.openapitools|
 |bigDecimalAsString|Treat BigDecimal values as Strings to avoid precision loss.| |false|
 |booleanGetterPrefix|Set booleanGetterPrefix| |get|

docs/generators/java-undertow-server.md

@@ -27,6 +27,7 @@ These options may be applied as additional-properties (cli) or configOptions (pl
 |artifactId|artifactId in generated pom.xml. This also becomes part of the generated library's filename| |openapi-undertow-server|
 |artifactUrl|artifact URL in generated pom.xml| |https://github.com/openapitools/openapi-generator|
 |artifactVersion|artifact version in generated pom.xml. This also becomes part of the generated library's filename| |1.0.0|
+|autosetConstants|Automatically set Required Params having a Single enum value i.e. Constants in generated code| |false|
 |bigDecimalAsString|Treat BigDecimal values as Strings to avoid precision loss.| |false|
 |booleanGetterPrefix|Set booleanGetterPrefix| |get|
 |camelCaseDollarSign|Fix camelCase when starting with $ sign. when true : $Value when false : $value| |false|

docs/generators/java-vertx-web.md

@@ -27,6 +27,7 @@ These options may be applied as additional-properties (cli) or configOptions (pl
 |artifactId|artifactId in generated pom.xml. This also becomes part of the generated library's filename| |openapi-java-vertx-web-server|
 |artifactUrl|artifact URL in generated pom.xml| |https://github.com/openapitools/openapi-generator|
 |artifactVersion|artifact version in generated pom.xml. This also becomes part of the generated library's filename| |1.0.0-SNAPSHOT|
+|autosetConstants|Automatically set Required Params having a Single enum value i.e. Constants in generated code| |false|
 |bigDecimalAsString|Treat BigDecimal values as Strings to avoid precision loss.| |false|
 |booleanGetterPrefix|Set booleanGetterPrefix| |get|
 |camelCaseDollarSign|Fix camelCase when starting with $ sign. when true : $Value when false : $value| |false|

docs/generators/java-vertx.md

@@ -27,6 +27,7 @@ These options may be applied as additional-properties (cli) or configOptions (pl
 |artifactId|artifactId in generated pom.xml. This also becomes part of the generated library's filename| |openapi-java-vertx-server|
 |artifactUrl|artifact URL in generated pom.xml| |https://github.com/openapitools/openapi-generator|
 |artifactVersion|artifact version in generated pom.xml. This also becomes part of the generated library's filename| |1.0.0-SNAPSHOT|
+|autosetConstants|Automatically set Required Params having a Single enum value i.e. Constants in generated code| |false|
 |bigDecimalAsString|Treat BigDecimal values as Strings to avoid precision loss.| |false|
 |booleanGetterPrefix|Set booleanGetterPrefix| |get|
 |camelCaseDollarSign|Fix camelCase when starting with $ sign. when true : $Value when false : $value| |false|

docs/generators/java.md

@@ -29,6 +29,7 @@ These options may be applied as additional-properties (cli) or configOptions (pl
 |artifactUrl|artifact URL in generated pom.xml| |https://github.com/openapitools/openapi-generator|
 |artifactVersion|artifact version in generated pom.xml. This also becomes part of the generated library's filename| |1.0.0|
 |asyncNative|If true, async handlers will be used, instead of the sync version| |false|
+|autosetConstants|Automatically set Required Params having a Single enum value i.e. Constants in generated code| |false|
 |bigDecimalAsString|Treat BigDecimal values as Strings to avoid precision loss.| |false|
 |booleanGetterPrefix|Set booleanGetterPrefix| |get|
 |camelCaseDollarSign|Fix camelCase when starting with $ sign. when true : $Value when false : $value| |false|

docs/generators/jaxrs-cxf-cdi.md

@@ -27,6 +27,7 @@ These options may be applied as additional-properties (cli) or configOptions (pl
 |artifactId|artifactId in generated pom.xml. This also becomes part of the generated library's filename| |openapi-jaxrs-cxf-cdi-server|
 |artifactUrl|artifact URL in generated pom.xml| |https://github.com/openapitools/openapi-generator|
 |artifactVersion|artifact version in generated pom.xml. This also becomes part of the generated library's filename| |1.0.0|
+|autosetConstants|Automatically set Required Params having a Single enum value i.e. Constants in generated code| |false|
 |bigDecimalAsString|Treat BigDecimal values as Strings to avoid precision loss.| |false|
 |booleanGetterPrefix|Set booleanGetterPrefix| |get|
 |camelCaseDollarSign|Fix camelCase when starting with $ sign. when true : $Value when false : $value| |false|

docs/generators/jaxrs-cxf-client.md

@@ -27,6 +27,7 @@ These options may be applied as additional-properties (cli) or configOptions (pl
 |artifactId|artifactId in generated pom.xml. This also becomes part of the generated library's filename| |openapi-jaxrs-client|
 |artifactUrl|artifact URL in generated pom.xml| |https://github.com/openapitools/openapi-generator|
 |artifactVersion|artifact version in generated pom.xml. This also becomes part of the generated library's filename| |1.0.0|
+|autosetConstants|Automatically set Required Params having a Single enum value i.e. Constants in generated code| |false|
 |bigDecimalAsString|Treat BigDecimal values as Strings to avoid precision loss.| |false|
 |booleanGetterPrefix|Set booleanGetterPrefix| |get|
 |camelCaseDollarSign|Fix camelCase when starting with $ sign. when true : $Value when false : $value| |false|

docs/generators/jaxrs-cxf-extended.md

@@ -28,6 +28,7 @@ These options may be applied as additional-properties (cli) or configOptions (pl
 |artifactId|artifactId in generated pom.xml. This also becomes part of the generated library's filename| |openapi-cxf-server|
 |artifactUrl|artifact URL in generated pom.xml| |https://github.com/openapitools/openapi-generator|
 |artifactVersion|artifact version in generated pom.xml. This also becomes part of the generated library's filename| |1.0.0|
+|autosetConstants|Automatically set Required Params having a Single enum value i.e. Constants in generated code| |false|
 |bigDecimalAsString|Treat BigDecimal values as Strings to avoid precision loss.| |false|
 |booleanGetterPrefix|Set booleanGetterPrefix| |get|
 |camelCaseDollarSign|Fix camelCase when starting with $ sign. when true : $Value when false : $value| |false|

docs/generators/jaxrs-cxf.md

@@ -28,6 +28,7 @@ These options may be applied as additional-properties (cli) or configOptions (pl
 |artifactId|artifactId in generated pom.xml. This also becomes part of the generated library's filename| |openapi-cxf-server|
 |artifactUrl|artifact URL in generated pom.xml| |https://github.com/openapitools/openapi-generator|
 |artifactVersion|artifact version in generated pom.xml. This also becomes part of the generated library's filename| |1.0.0|
+|autosetConstants|Automatically set Required Params having a Single enum value i.e. Constants in generated code| |false|
 |bigDecimalAsString|Treat BigDecimal values as Strings to avoid precision loss.| |false|
 |booleanGetterPrefix|Set booleanGetterPrefix| |get|
 |camelCaseDollarSign|Fix camelCase when starting with $ sign. when true : $Value when false : $value| |false|

docs/generators/jaxrs-jersey.md

@@ -27,6 +27,7 @@ These options may be applied as additional-properties (cli) or configOptions (pl
 |artifactId|artifactId in generated pom.xml. This also becomes part of the generated library's filename| |openapi-jaxrs-server|
 |artifactUrl|artifact URL in generated pom.xml| |https://github.com/openapitools/openapi-generator|
 |artifactVersion|artifact version in generated pom.xml. This also becomes part of the generated library's filename| |1.0.0|
+|autosetConstants|Automatically set Required Params having a Single enum value i.e. Constants in generated code| |false|
 |bigDecimalAsString|Treat BigDecimal values as Strings to avoid precision loss.| |false|
 |booleanGetterPrefix|Set booleanGetterPrefix| |get|
 |camelCaseDollarSign|Fix camelCase when starting with $ sign. when true : $Value when false : $value| |false|

docs/generators/jaxrs-resteasy-eap.md

@@ -27,6 +27,7 @@ These options may be applied as additional-properties (cli) or configOptions (pl
 |artifactId|artifactId in generated pom.xml. This also becomes part of the generated library's filename| |openapi-jaxrs-resteasy-eap-server|
 |artifactUrl|artifact URL in generated pom.xml| |https://github.com/openapitools/openapi-generator|
 |artifactVersion|artifact version in generated pom.xml. This also becomes part of the generated library's filename| |1.0.0|
+|autosetConstants|Automatically set Required Params having a Single enum value i.e. Constants in generated code| |false|
 |bigDecimalAsString|Treat BigDecimal values as Strings to avoid precision loss.| |false|
 |booleanGetterPrefix|Set booleanGetterPrefix| |get|
 |camelCaseDollarSign|Fix camelCase when starting with $ sign. when true : $Value when false : $value| |false|

docs/generators/jaxrs-resteasy.md

@@ -27,6 +27,7 @@ These options may be applied as additional-properties (cli) or configOptions (pl
 |artifactId|artifactId in generated pom.xml. This also becomes part of the generated library's filename| |openapi-jaxrs-resteasy-server|
 |artifactUrl|artifact URL in generated pom.xml| |https://github.com/openapitools/openapi-generator|
 |artifactVersion|artifact version in generated pom.xml. This also becomes part of the generated library's filename| |1.0.0|
+|autosetConstants|Automatically set Required Params having a Single enum value i.e. Constants in generated code| |false|
 |bigDecimalAsString|Treat BigDecimal values as Strings to avoid precision loss.| |false|
 |booleanGetterPrefix|Set booleanGetterPrefix| |get|
 |camelCaseDollarSign|Fix camelCase when starting with $ sign. when true : $Value when false : $value| |false|

docs/generators/jaxrs-spec.md

@@ -27,6 +27,7 @@ These options may be applied as additional-properties (cli) or configOptions (pl
 |artifactId|artifactId in generated pom.xml. This also becomes part of the generated library's filename| |openapi-jaxrs-server|
 |artifactUrl|artifact URL in generated pom.xml| |https://github.com/openapitools/openapi-generator|
 |artifactVersion|artifact version in generated pom.xml. This also becomes part of the generated library's filename| |1.0.0|
+|autosetConstants|Automatically set Required Params having a Single enum value i.e. Constants in generated code| |false|
 |bigDecimalAsString|Treat BigDecimal values as Strings to avoid precision loss.| |false|
 |booleanGetterPrefix|Set booleanGetterPrefix| |get|
 |camelCaseDollarSign|Fix camelCase when starting with $ sign. when true : $Value when false : $value| |false|

docs/generators/spring.md

@@ -30,6 +30,7 @@ These options may be applied as additional-properties (cli) or configOptions (pl
 |artifactUrl|artifact URL in generated pom.xml| |https://github.com/openapitools/openapi-generator|
 |artifactVersion|artifact version in generated pom.xml. This also becomes part of the generated library's filename| |1.0.0|
 |async|use async Callable controllers| |false|
+|autosetConstants|Automatically set Required Params having a Single enum value i.e. Constants in generated code| |false|
 |basePackage|base package (invokerPackage) for generated code| |org.openapitools|
 |bigDecimalAsString|Treat BigDecimal values as Strings to avoid precision loss.| |false|
 |booleanGetterPrefix|Set booleanGetterPrefix| |get|

modules/openapi-generator-gradle-plugin/src/main/kotlin/org/openapitools/generator/gradle/plugin/extensions/OpenApiGeneratorValidateExtension.kt

@@ -33,12 +33,5 @@ open class OpenApiGeneratorValidateExtension(project: Project) {
     /**
      * Whether to offer recommendations related to the validated specification document.
      */
-    val recommend = project.objects.property<Boolean?>()
-
-    init {
-        applyDefaults()
-    }
-
-    @Suppress("MemberVisibilityCanBePrivate")
-    fun applyDefaults() = recommend.set(true)
+    val recommend = project.objects.property<Boolean>().convention(true)
 }

modules/openapi-generator-gradle-plugin/src/main/kotlin/org/openapitools/generator/gradle/plugin/tasks/ValidateTask.kt

@@ -58,7 +58,7 @@ open class ValidateTask : DefaultTask() {
 
     @Optional
     @Input
-    val recommend = project.objects.property<Boolean?>()
+    val recommend = project.objects.property<Boolean>().convention(true)
 
     @get:Internal
     @set:Option(option = "input", description = "The input specification.")

modules/openapi-generator-gradle-plugin/src/test/kotlin/ValidateTaskDslTest.kt

@@ -144,4 +144,161 @@ class ValidateTaskDslTest : TestBase() {
             "Expected a failed run, but found ${result.task(":openApiValidate")?.outcome}"
         )
     }
+
+    @Test(dataProvider = "gradle_version_provider")
+    fun `validateGoodSpec as defined task should succeed on valid spec`(gradleVersion: String?) {
+        // Arrange
+        val projectFiles = mapOf(
+            "spec.yaml" to javaClass.classLoader.getResourceAsStream("specs/petstore-v3.0.yaml")
+        )
+
+        withProject(
+            """
+            | plugins {
+            |   id 'org.openapi.generator'
+            | }
+            |
+            | task validateGoodSpec(type: org.openapitools.generator.gradle.plugin.tasks.ValidateTask) {
+            |    inputSpec.set(file("spec.yaml").absolutePath)
+            | }
+        """.trimMargin(), projectFiles
+        )
+
+        // Act
+        val result = getGradleRunner(gradleVersion)
+            .withProjectDir(temp)
+            .withArguments("validateGoodSpec")
+            .withPluginClasspath()
+            .build()
+
+        // Assert
+        assertTrue(
+            result.output.contains("Spec is valid."),
+            "Unexpected/no message presented to the user for a valid spec."
+        )
+        assertEquals(
+            SUCCESS, result.task(":validateGoodSpec")?.outcome,
+            "Expected a successful run, but found ${result.task(":validateGoodSpec")?.outcome}"
+        )
+    }
+
+    @Test(dataProvider = "gradle_version_provider")
+    fun `validateBadSpec as defined task should fail on invalid spec`(gradleVersion: String?) {
+        // Arrange
+        val projectFiles = mapOf(
+            "spec.yaml" to javaClass.classLoader.getResourceAsStream("specs/petstore-v3.0-invalid.yaml")
+        )
+        withProject(
+            """
+            | plugins {
+            |   id 'org.openapi.generator'
+            | }
+            |
+            | task validateBadSpec(type: org.openapitools.generator.gradle.plugin.tasks.ValidateTask) {
+            |    inputSpec.set(file("spec.yaml").absolutePath)
+            | }
+        """.trimMargin(), projectFiles
+        )
+
+        // Act
+        val result = getGradleRunner(gradleVersion)
+            .withProjectDir(temp)
+            .withArguments("validateBadSpec")
+            .withPluginClasspath()
+            .buildAndFail()
+
+        // Assert
+        assertTrue(
+            result.output.contains("Spec is invalid."),
+            "Unexpected/no message presented to the user for an invalid spec."
+        )
+        assertEquals(
+            FAILED, result.task(":validateBadSpec")?.outcome,
+            "Expected a failed run, but found ${result.task(":validateBadSpec")?.outcome}"
+        )
+    }
+
+    @Test(dataProvider = "gradle_version_provider")
+    fun `openApiValidate should succeed with recommendations on valid spec`(gradleVersion: String?) {
+        // Arrange
+        val projectFiles = mapOf(
+            "spec.yaml" to javaClass.classLoader.getResourceAsStream("specs/petstore-v3.0-recommend.yaml")
+        )
+
+        // recommend = true is the default
+        withProject(
+            """
+            | plugins {
+            |   id 'org.openapi.generator'
+            | }
+            |
+            | openApiValidate {
+            |   inputSpec = file("spec.yaml").absolutePath
+            | }
+        """.trimMargin(), projectFiles
+        )
+
+        // Act
+        val result = getGradleRunner(gradleVersion)
+            .withProjectDir(temp)
+            .withArguments("openApiValidate")
+            .withPluginClasspath()
+            .build()
+
+        // Assert
+        assertTrue(
+            result.output.contains("Spec is valid."),
+            "Unexpected/no message presented to the user for a valid spec."
+        )
+        assertTrue(
+            result.output.contains("Spec has issues or recommendations."),
+            "Unexpected/no recommendations message presented to the user for a valid spec."
+        )
+        assertEquals(
+            SUCCESS, result.task(":openApiValidate")?.outcome,
+            "Expected a successful run, but found ${result.task(":openApiValidate")?.outcome}"
+        )
+    }
+
+    @Test(dataProvider = "gradle_version_provider")
+    fun `openApiValidate should succeed without recommendations on valid spec`(gradleVersion: String?) {
+        // Arrange
+        val projectFiles = mapOf(
+            "spec.yaml" to javaClass.classLoader.getResourceAsStream("specs/petstore-v3.0-recommend.yaml")
+        )
+
+        withProject(
+            """
+            | plugins {
+            |   id 'org.openapi.generator'
+            | }
+            |
+            | openApiValidate {
+            |   inputSpec = file("spec.yaml").absolutePath
+            |   recommend = false
+            | }
+        """.trimMargin(), projectFiles
+        )
+
+        // Act
+        val result = getGradleRunner(gradleVersion)
+            .withProjectDir(temp)
+            .withArguments("openApiValidate")
+            .withPluginClasspath()
+            .build()
+
+        // Assert
+        assertTrue(
+            result.output.contains("Spec is valid."),
+            "Unexpected/no message presented to the user for a valid spec."
+        )
+        assertTrue(
+            result.output.contains("Spec has issues or recommendations.").not(),
+            "Unexpected/recommendations message presented to the user for a valid spec"
+        )
+        assertEquals(
+            SUCCESS, result.task(":openApiValidate")?.outcome,
+            "Expected a successful run, but found ${result.task(":openApiValidate")?.outcome}"
+        )
+    }
 }

modules/openapi-generator-gradle-plugin/src/test/resources/specs/petstore-v3.0-recommend.yaml

@@ -0,0 +1,114 @@
+openapi: "3.0.0"
+info:
+  version: 1.0.0
+  title: Swagger Petstore
+  license:
+    name: MIT
+servers:
+  - url: http://petstore.swagger.io/v1
+paths:
+  /pets:
+    get:
+      summary: List all pets
+      operationId: listPets
+      tags:
+        - pets
+      parameters:
+        - name: limit
+          in: query
+          description: How many items to return at one time (max 100)
+          required: false
+          schema:
+            type: integer
+            format: int32
+      requestBody: # warning `API GET/HEAD defined with request body`
+        content:
+          application/json:
+            schema:
+              $ref: "#/components/schemas/Pets"
+      responses:
+        '200':
+          description: A paged array of pets
+          headers:
+            x-next:
+              description: A link to the next page of responses
+              schema:
+                type: string
+          content:
+            application/json:
+              schema:
+                $ref: "#/components/schemas/Pets"
+        default:
+          description: unexpected error
+          content:
+            application/json:
+              schema:
+                $ref: "#/components/schemas/Error"
+    post:
+      summary: Create a pet
+      operationId: createPets
+      tags:
+        - pets
+      responses:
+        '201':
+          description: Null response
+        default:
+          description: unexpected error
+          content:
+            application/json:
+              schema:
+                $ref: "#/components/schemas/Error"
+  /pets/{petId}:
+    get:
+      summary: Info for a specific pet
+      operationId: showPetById
+      tags:
+        - pets
+      parameters:
+        - name: petId
+          in: path
+          required: true
+          description: The id of the pet to retrieve
+          schema:
+            type: string
+      responses:
+        '200':
+          description: Expected response to a valid request
+          content:
+            application/json:
+              schema:
+                $ref: "#/components/schemas/Pets"
+        default:
+          description: unexpected error
+          content:
+            application/json:
+              schema:
+                $ref: "#/components/schemas/Error"
+components:
+  schemas:
+    Pet:
+      required:
+        - id
+        - name
+      properties:
+        id:
+          type: integer
+          format: int64
+        name:
+          type: string
+        tag:
+          type: string
+    Pets:
+      type: array
+      items:
+        $ref: "#/components/schemas/Pet"
+    Error:
+      required:
+        - code
+        - message
+      properties:
+        code:
+          type: integer
+          format: int32
+        message:
+          type: string

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

@@ -30,7 +30,7 @@ public class CodegenOperation {
             hasVersionHeaders = false, hasVersionQueryParams = false,
             isResponseBinary = false, isResponseFile = false, isResponseOptional = false, hasReference = false, defaultReturnType = false,
             isRestfulIndex, isRestfulShow, isRestfulCreate, isRestfulUpdate, isRestfulDestroy,
-            isRestful, isDeprecated, isCallbackRequest, uniqueItems, hasDefaultResponse = false,
+            isRestful, isDeprecated, isCallbackRequest, uniqueItems, hasDefaultResponse = false, hasConstantParams = false,
             hasErrorResponseObject; // if 4xx, 5xx responses have at least one error object defined
     public CodegenProperty returnProperty;
     public String path, operationId, returnType, returnFormat, httpMethod, returnBaseType,
@@ -45,6 +45,7 @@ public class CodegenOperation {
     public List<CodegenParameter> queryParams = new ArrayList<CodegenParameter>();
     public List<CodegenParameter> headerParams = new ArrayList<CodegenParameter>();
     public List<CodegenParameter> implicitHeadersParams = new ArrayList<CodegenParameter>();
+    public List<CodegenParameter> constantParams = new ArrayList<CodegenParameter>();
     public List<CodegenParameter> formParams = new ArrayList<CodegenParameter>();
     public List<CodegenParameter> cookieParams = new ArrayList<CodegenParameter>();
     public List<CodegenParameter> requiredParams = new ArrayList<CodegenParameter>();
@@ -392,6 +393,7 @@ public class CodegenOperation {
         sb.append(", operationIdLowerCase='").append(operationIdLowerCase).append('\'');
         sb.append(", operationIdCamelCase='").append(operationIdCamelCase).append('\'');
         sb.append(", operationIdSnakeCase='").append(operationIdSnakeCase).append('\'');
+        sb.append(", constantParams='").append(constantParams).append('\'');
         sb.append('}');
         return sb.toString();
     }
@@ -472,7 +474,8 @@ public class CodegenOperation {
                 Objects.equals(operationIdOriginal, that.operationIdOriginal) &&
                 Objects.equals(operationIdLowerCase, that.operationIdLowerCase) &&
                 Objects.equals(operationIdCamelCase, that.operationIdCamelCase) &&
-                Objects.equals(operationIdSnakeCase, that.operationIdSnakeCase);
+                Objects.equals(operationIdSnakeCase, that.operationIdSnakeCase) &&
+                Objects.equals(constantParams, that.constantParams);
     }
 
     @Override
@@ -488,6 +491,6 @@ public class CodegenOperation {
                 pathParams, queryParams, headerParams, formParams, cookieParams, requiredParams, returnProperty, optionalParams,
                 authMethods, tags, responses, callbacks, imports, examples, requestBodyExamples, externalDocs,
                 vendorExtensions, nickname, operationIdOriginal, operationIdLowerCase, operationIdCamelCase,
-                operationIdSnakeCase, hasErrorResponseObject, requiredAndNotNullableParams, notNullableParams);
+                operationIdSnakeCase, hasErrorResponseObject, requiredAndNotNullableParams, notNullableParams, constantParams);
     }
 }

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

@@ -112,6 +112,9 @@ public class CodegenParameter implements IJsonSchemaValidationProperties {
      * See http://json-schema.org/latest/json-schema-validation.html#anchor14
      */
     public Number multipleOf;
+
+    public String constant; // for const or enum with a single item
+
     private Integer maxProperties;
     private Integer minProperties;
     public boolean isNull;
@@ -164,6 +167,7 @@ public class CodegenParameter implements IJsonSchemaValidationProperties {
         output.uniqueItems = this.uniqueItems;
         output.setUniqueItemsBoolean(this.uniqueItemsBoolean);
         output.multipleOf = this.multipleOf;
+        output.constant = this.constant;
         output.jsonSchema = this.jsonSchema;
         output.defaultValue = this.defaultValue;
         output.enumDefaultValue = this.enumDefaultValue;
@@ -260,7 +264,20 @@ public class CodegenParameter implements IJsonSchemaValidationProperties {
 
     @Override
     public int hashCode() {
-        return Objects.hash(isFormParam, isQueryParam, isPathParam, isHeaderParam, isCookieParam, isBodyParam, isContainer, isCollectionFormatMulti, isPrimitiveType, isModel, isExplode, baseName, paramName, dataType, datatypeWithEnum, dataFormat, collectionFormat, description, unescapedDescription, baseType, containerType, containerTypeMapped, defaultValue, enumDefaultValue, enumName, style, isDeepObject, isMatrix, isAllowEmptyValue, example, examples, jsonSchema, isString, isNumeric, isInteger, isLong, isNumber, isFloat, isDouble, isDecimal, isByteArray, isBinary, isBoolean, isDate, isDateTime, isUuid, isUri, isEmail, isPassword, isFreeFormObject, isAnyType, isArray, isMap, isFile, isEnum, isEnumRef, _enum, allowableValues, items, mostInnerItems, additionalProperties, vars, requiredVars, vendorExtensions, hasValidation, getMaxProperties(), getMinProperties(), isNullable, isDeprecated, required, getMaximum(), getExclusiveMaximum(), getMinimum(), getExclusiveMinimum(), getMaxLength(), getMinLength(), getPattern(), getMaxItems(), getMinItems(), getUniqueItems(), contentType, multipleOf, isNull, isVoid, additionalPropertiesIsAnyType, hasVars, hasRequired, isShort, isUnboundedInteger, hasDiscriminatorWithNonEmptyMapping, composedSchemas, hasMultipleTypes, schema, content, requiredVarsMap, ref, uniqueItemsBoolean, schemaIsFromAdditionalProperties);
+        return Objects.hash(isFormParam, isQueryParam, isPathParam, isHeaderParam, isCookieParam, isBodyParam,
+                isContainer, isCollectionFormatMulti, isPrimitiveType, isModel, isExplode, baseName, paramName,
+                dataType, datatypeWithEnum, dataFormat, collectionFormat, description, unescapedDescription, baseType,
+                containerType, containerTypeMapped, defaultValue, enumDefaultValue, enumName, style, isDeepObject,
+                isMatrix, isAllowEmptyValue, example, examples, jsonSchema, isString, isNumeric, isInteger, isLong,
+                isNumber, isFloat, isDouble, isDecimal, isByteArray, isBinary, isBoolean, isDate, isDateTime, isUuid,
+                isUri, isEmail, isPassword, isFreeFormObject, isAnyType, isArray, isMap, isFile, isEnum, isEnumRef,
+                _enum, allowableValues, items, mostInnerItems, additionalProperties, vars, requiredVars,
+                vendorExtensions, hasValidation, getMaxProperties(), getMinProperties(), isNullable, isDeprecated,
+                required, getMaximum(), getExclusiveMaximum(), getMinimum(), getExclusiveMinimum(), getMaxLength(),
+                getMinLength(), getPattern(), getMaxItems(), getMinItems(), getUniqueItems(), contentType, multipleOf,
+                isNull, isVoid, additionalPropertiesIsAnyType, hasVars, hasRequired, isShort, isUnboundedInteger,
+                hasDiscriminatorWithNonEmptyMapping, composedSchemas, hasMultipleTypes, schema, content,
+                requiredVarsMap, ref, uniqueItemsBoolean, schemaIsFromAdditionalProperties, constant);
     }
 
     @Override
@@ -365,6 +382,7 @@ public class CodegenParameter implements IJsonSchemaValidationProperties {
                 Objects.equals(getMaxItems(), that.getMaxItems()) &&
                 Objects.equals(getMinItems(), that.getMinItems()) &&
                 Objects.equals(contentType, that.contentType) &&
+                Objects.equals(constant, that.constant) &&
                 Objects.equals(multipleOf, that.multipleOf);
     }
 
@@ -465,6 +483,7 @@ public class CodegenParameter implements IJsonSchemaValidationProperties {
         sb.append(", uniqueItemsBoolean=").append(uniqueItemsBoolean);
         sb.append(", contentType=").append(contentType);
         sb.append(", multipleOf=").append(multipleOf);
+        sb.append(", constant=").append(constant);
         sb.append(", isNull=").append(isNull);
         sb.append(", isVoid=").append(isVoid);
         sb.append(", getAdditionalPropertiesIsAnyType=").append(additionalPropertiesIsAnyType);

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

@@ -211,6 +211,9 @@ public class CodegenProperty implements Cloneable, IJsonSchemaValidationProperti
     private LinkedHashMap<String, List<String>> dependentRequired;
     private CodegenProperty contains;
 
+    // JSON Schema keywords
+    private String constant; // for `const`
+
     @Override
     public CodegenProperty getContains() {
         return contains;
@@ -1036,6 +1039,14 @@ public class CodegenProperty implements Cloneable, IJsonSchemaValidationProperti
         return isEnum || isEnumRef;
     }
 
+    public void setConstant(String constant) {
+        this.constant = constant;
+    }
+
+    public String getConstant() {
+        return constant;
+    }
+
     @Override
     public String toString() {
         final StringBuilder sb = new StringBuilder("CodegenProperty{");
@@ -1150,6 +1161,7 @@ public class CodegenProperty implements Cloneable, IJsonSchemaValidationProperti
         sb.append(", format=").append(format);
         sb.append(", dependentRequired=").append(dependentRequired);
         sb.append(", contains=").append(contains);
+        sb.append(", constant=").append(constant);
         sb.append('}');
         return sb.toString();
     }
@@ -1266,7 +1278,8 @@ public class CodegenProperty implements Cloneable, IJsonSchemaValidationProperti
                 Objects.equals(xmlPrefix, that.xmlPrefix) &&
                 Objects.equals(xmlName, that.xmlName) &&
                 Objects.equals(xmlNamespace, that.xmlNamespace) &&
-                Objects.equals(multipleOf, that.multipleOf);
+                Objects.equals(multipleOf, that.multipleOf) &&
+                Objects.equals(constant, that.getConstant());
     }
 
     @Override
@@ -1288,6 +1301,6 @@ public class CodegenProperty implements Cloneable, IJsonSchemaValidationProperti
                 xmlNamespace, isXmlWrapped, isNull, isVoid, additionalPropertiesIsAnyType, hasVars, hasRequired,
                 hasDiscriminatorWithNonEmptyMapping, composedSchemas, hasMultipleTypes, requiredVarsMap,
                 ref, uniqueItemsBoolean, schemaIsFromAdditionalProperties, isBooleanSchemaTrue, isBooleanSchemaFalse,
-                format, dependentRequired, contains);
+                format, dependentRequired, contains, constant);
     }
 }

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

@@ -478,6 +478,11 @@ public class DefaultCodegen implements CodegenConfig {
         for (Map.Entry<String, ModelsMap> entry : objs.entrySet()) {
             CodegenModel model = ModelUtils.getModelByName(entry.getKey(), objs);
 
+            if (model == null) {
+                LOGGER.warn("Null model found in postProcessAllModels: {}", entry.getKey());
+                continue;
+            }
+
             // add the model to the discriminator's mapping so templates have access to more than just the string to string mapping
             if (model.discriminator != null && model.discriminator.getMappedModels() != null) {
                 for (CodegenDiscriminator.MappedModel mappedModel : model.discriminator.getMappedModels()) {
@@ -4588,6 +4593,7 @@ public class DefaultCodegen implements CodegenConfig {
         List<CodegenParameter> optionalParams = new ArrayList<>();
         List<CodegenParameter> requiredAndNotNullableParams = new ArrayList<>();
         List<CodegenParameter> notNullableParams = new ArrayList<>();
+        List<CodegenParameter> constantParams = new ArrayList<>();
 
         CodegenParameter bodyParam = null;
         RequestBody requestBody = operation.getRequestBody();
@@ -4651,20 +4657,22 @@ public class DefaultCodegen implements CodegenConfig {
                     }
                 }
 
-                allParams.add(p);
-
-                if (param instanceof QueryParameter || "query".equalsIgnoreCase(param.getIn())) {
-                    queryParams.add(p.copy());
-                } else if (param instanceof PathParameter || "path".equalsIgnoreCase(param.getIn())) {
-                    pathParams.add(p.copy());
-                } else if (param instanceof HeaderParameter || "header".equalsIgnoreCase(param.getIn())) {
-                    headerParams.add(p.copy());
-                } else if (param instanceof CookieParameter || "cookie".equalsIgnoreCase(param.getIn())) {
-                    cookieParams.add(p.copy());
-                } else {
-                    LOGGER.warn("Unknown parameter type {} for {}", p.baseType, p.baseName);
+                if (p.constant != null) { // for constant
+                    constantParams.add(p.copy());
+                } else { // a typical parameter
+                    allParams.add(p);
+                    if (param instanceof QueryParameter || "query".equalsIgnoreCase(param.getIn())) {
+                        queryParams.add(p.copy());
+                    } else if (param instanceof PathParameter || "path".equalsIgnoreCase(param.getIn())) {
+                        pathParams.add(p.copy());
+                    } else if (param instanceof HeaderParameter || "header".equalsIgnoreCase(param.getIn())) {
+                        headerParams.add(p.copy());
+                    } else if (param instanceof CookieParameter || "cookie".equalsIgnoreCase(param.getIn())) {
+                        cookieParams.add(p.copy());
+                    } else {
+                        LOGGER.warn("Unknown parameter type {} for {}", p.baseType, p.baseName);
+                    }
                 }
-
             }
         }
 
@@ -5350,6 +5358,26 @@ public class DefaultCodegen implements CodegenConfig {
         // set default value
         codegenParameter.defaultValue = toDefaultParameterValue(codegenProperty, parameterSchema);
 
+        // set constant
+        if (codegenParameter.getIsEnumOrRef()) { // enum with only 1 item
+            Schema enumSchema = ModelUtils.getReferencedSchema(openAPI, unaliasSchema(parameterSchema));
+            if (enumSchema.getEnum() != null && enumSchema.getEnum().size() == 1) { // only 1 element
+                codegenParameter.constant = toDefaultParameterValue(codegenProperty, enumSchema);
+            }
+        } else if (parameterSchema.getConst() != null) { // JSON Sschema keyword `const`
+            Schema temp = null;
+            Pattern pattern = Pattern.compile("-?\\d+(\\.\\d+)?");
+            String constantValue = String.valueOf(parameterSchema.getConst());
+            if (pattern.matcher(constantValue).matches()) { // numeric constant value
+                temp = new NumberSchema();
+                temp.setDefault(constantValue);
+            } else { // constant value is a string
+                temp = new StringSchema();
+                temp.setDefault(constantValue);
+            }
+            codegenParameter.constant = toDefaultParameterValue(temp);
+        }
+
         finishUpdatingParameter(codegenParameter, parameter);
         return codegenParameter;
     }
@@ -5977,6 +6005,10 @@ public class DefaultCodegen implements CodegenConfig {
     }
 
     private static Boolean isAliasOfSimpleTypes(Schema schema) {
+        if (schema == null) {
+            return false;
+        }
+
         return (!ModelUtils.isObjectSchema(schema)
                 && !ModelUtils.isArraySchema(schema)
                 && !ModelUtils.isMapSchema(schema)

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

@@ -1334,8 +1334,10 @@ public class DefaultGenerator implements Generator {
         for (Map.Entry<String, Schema> definitionsEntry : definitions.entrySet()) {
             String key = definitionsEntry.getKey();
             Schema schema = definitionsEntry.getValue();
-            if (schema == null)
-                throw new RuntimeException("schema cannot be null in processModels");
+            if (schema == null) {
+                LOGGER.warn("Schema {} cannot be null in processModels", key);
+                continue;
+            }
             CodegenModel cm = config.fromModel(key, schema);
             ModelMap mo = new ModelMap();
             mo.setModel(cm);

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

@@ -286,6 +286,11 @@ public class InlineModelResolver {
             if (props != null) {
                 for (String propName : props.keySet()) {
                     Schema prop = props.get(propName);
+
+                    if (prop == null) {
+                        continue;
+                    }
+
                     String schemaName = resolveModelName(prop.getTitle(), modelPrefix + "_" + propName);
                     // Recurse to create $refs for inner models
                     gatherInlineModels(prop, schemaName);
@@ -308,13 +313,15 @@ public class InlineModelResolver {
             if (schema.getAdditionalProperties() != null) {
                 if (schema.getAdditionalProperties() instanceof Schema) {
                     Schema inner = (Schema) schema.getAdditionalProperties();
-                    String schemaName = resolveModelName(schema.getTitle(), modelPrefix + this.inlineSchemaOptions.get("MAP_ITEM_SUFFIX"));
-                    // Recurse to create $refs for inner models
-                    gatherInlineModels(inner, schemaName);
-                    if (isModelNeeded(inner)) {
-                        // If this schema should be split into its own model, do so
-                        Schema refSchema = this.makeSchemaInComponents(schemaName, inner);
-                        schema.setAdditionalProperties(refSchema);
+                    if (inner != null) {
+                        String schemaName = resolveModelName(schema.getTitle(), modelPrefix + this.inlineSchemaOptions.get("MAP_ITEM_SUFFIX"));
+                        // Recurse to create $refs for inner models
+                        gatherInlineModels(inner, schemaName);
+                        if (isModelNeeded(inner)) {
+                            // If this schema should be split into its own model, do so
+                            Schema refSchema = this.makeSchemaInComponents(schemaName, inner);
+                            schema.setAdditionalProperties(refSchema);
+                        }
                     }
                 }
             }
@@ -334,10 +341,6 @@ public class InlineModelResolver {
         if (schema instanceof ArraySchema) {
             ArraySchema array = (ArraySchema) schema;
             Schema items = array.getItems();
-            /*if (items.getTitle() != null) {
-                LOGGER.info("schema title {}", items);
-                throw new RuntimeException("getTitle for array item is not null");
-            }*/
             if (items == null) {
                 LOGGER.error("Illegal schema found with array type but no items," +
                         " items must be defined for array schemas:\n " + schema.toString());
@@ -360,6 +363,9 @@ public class InlineModelResolver {
                 List<Schema> newAllOf = new ArrayList<Schema>();
                 boolean atLeastOneModel = false;
                 for (Object inner : schema.getAllOf()) {
+                    if (inner == null) {
+                        continue;
+                    }
                     String schemaName = resolveModelName(((Schema) inner).getTitle(), modelPrefix + "_allOf");
                     // Recurse to create $refs for inner models
                     gatherInlineModels((Schema) inner, schemaName);
@@ -392,6 +398,9 @@ public class InlineModelResolver {
             if (schema.getAnyOf() != null) {
                 List<Schema> newAnyOf = new ArrayList<Schema>();
                 for (Object inner : schema.getAnyOf()) {
+                    if (inner == null) {
+                        continue;
+                    }
                     String schemaName = resolveModelName(((Schema) inner).getTitle(), modelPrefix + "_anyOf");
                     // Recurse to create $refs for inner models
                     gatherInlineModels((Schema) inner, schemaName);
@@ -407,6 +416,9 @@ public class InlineModelResolver {
             if (schema.getOneOf() != null) {
                 List<Schema> newOneOf = new ArrayList<Schema>();
                 for (Object inner : schema.getOneOf()) {
+                    if (inner == null) {
+                        continue;
+                    }
                     String schemaName = resolveModelName(((Schema) inner).getTitle(), modelPrefix + "_oneOf");
                     // Recurse to create $refs for inner models
                     gatherInlineModels((Schema) inner, schemaName);
@@ -423,12 +435,14 @@ public class InlineModelResolver {
         // Check not schema
         if (schema.getNot() != null) {
             Schema not = schema.getNot();
-            String schemaName = resolveModelName(schema.getTitle(), modelPrefix + "_not");
-            // Recurse to create $refs for inner models
-            gatherInlineModels(not, schemaName);
-            if (isModelNeeded(not)) {
-                Schema refSchema = this.makeSchemaInComponents(schemaName, not);
-                schema.setNot(refSchema);
+            if (not != null) {
+                String schemaName = resolveModelName(schema.getTitle(), modelPrefix + "_not");
+                // Recurse to create $refs for inner models
+                gatherInlineModels(not, schemaName);
+                if (isModelNeeded(not)) {
+                    Schema refSchema = this.makeSchemaInComponents(schemaName, not);
+                    schema.setNot(refSchema);
+                }
             }
         }
     }
@@ -629,6 +643,9 @@ public class InlineModelResolver {
         List<String> modelNames = new ArrayList<String>(models.keySet());
         for (String modelName : modelNames) {
             Schema model = models.get(modelName);
+            if (model == null) {
+                continue;
+            }
             if (ModelUtils.isAnyOf(model)) { // contains anyOf only
                 gatherInlineModels(model, modelName);
             } else if (ModelUtils.isOneOf(model)) { // contains oneOf only

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

@@ -527,7 +527,7 @@ public abstract class AbstractCSharpCodegen extends DefaultCodegen implements Co
             // GrandparentAnimal has a discriminator, but no oneOf nor anyOf
             // modules\openapi-generator\src\test\resources\3_0\csharp\petstore-with-fake-endpoints-models-for-testing-with-http-signature.yaml
             model.setHasDiscriminatorWithNonEmptyMapping(
-                    ((model.anyOf != null && model.anyOf.size() > 0) || (model.anyOf != null && model.oneOf.size() > 0)) &&
+                    ((model.anyOf != null && model.anyOf.size() > 0) || (model.oneOf != null && model.oneOf.size() > 0)) &&
                             model.discriminator != null &&
                             model.discriminator.getMappedModels() != null &&
                             model.discriminator.getMappedModels().size() > 0);

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

@@ -83,6 +83,7 @@ public abstract class AbstractJavaCodegen extends DefaultCodegen implements Code
     public static final String TEST_OUTPUT = "testOutput";
     public static final String IMPLICIT_HEADERS = "implicitHeaders";
     public static final String IMPLICIT_HEADERS_REGEX = "implicitHeadersRegex";
+    public static final String AUTOSET_CONSTANTS = "autosetConstants";
     public static final String JAVAX_PACKAGE = "javaxPackage";
     public static final String USE_JAKARTA_EE = "useJakartaEe";
     public static final String CONTAINER_DEFAULT_TO_NULL = "containerDefaultToNull";
@@ -137,6 +138,7 @@ public abstract class AbstractJavaCodegen extends DefaultCodegen implements Code
     protected AnnotationLibrary annotationLibrary;
     protected boolean implicitHeaders = false;
     protected String implicitHeadersRegex = null;
+    protected boolean autosetConstants = false;
     protected boolean camelCaseDollarSign = false;
     protected boolean useJakartaEe = false;
     protected boolean containerDefaultToNull = false;
@@ -277,6 +279,7 @@ public abstract class AbstractJavaCodegen extends DefaultCodegen implements Code
         cliOptions.add(CliOption.newBoolean(OPENAPI_NULLABLE, "Enable OpenAPI Jackson Nullable library", this.openApiNullable));
         cliOptions.add(CliOption.newBoolean(IMPLICIT_HEADERS, "Skip header parameters in the generated API methods using @ApiImplicitParams annotation.", implicitHeaders));
         cliOptions.add(CliOption.newString(IMPLICIT_HEADERS_REGEX, "Skip header parameters that matches given regex in the generated API methods using @ApiImplicitParams annotation. Note: this parameter is ignored when implicitHeaders=true"));
+        cliOptions.add(CliOption.newBoolean(AUTOSET_CONSTANTS, "Automatically set Required Params having a Single enum value i.e. Constants in generated code", autosetConstants));
         cliOptions.add(CliOption.newBoolean(CAMEL_CASE_DOLLAR_SIGN, "Fix camelCase when starting with $ sign. when true : $Value when false : $value"));
         cliOptions.add(CliOption.newBoolean(USE_JAKARTA_EE, "whether to use Jakarta EE namespace instead of javax"));
         cliOptions.add(CliOption.newBoolean(CONTAINER_DEFAULT_TO_NULL, "Set containers (array, set, map) default to null"));
@@ -563,6 +566,10 @@ public abstract class AbstractJavaCodegen extends DefaultCodegen implements Code
             this.setImplicitHeadersRegex(additionalProperties.get(IMPLICIT_HEADERS_REGEX).toString());
         }
 
+        if (additionalProperties.containsKey(AUTOSET_CONSTANTS)) {
+            this.setAutosetConstants(Boolean.parseBoolean(additionalProperties.get(AUTOSET_CONSTANTS).toString()));
+        }
+
         if (additionalProperties.containsKey(CAMEL_CASE_DOLLAR_SIGN)) {
             this.setCamelCaseDollarSign(Boolean.parseBoolean(additionalProperties.get(CAMEL_CASE_DOLLAR_SIGN).toString()));
         }
@@ -1578,6 +1585,7 @@ public abstract class AbstractJavaCodegen extends DefaultCodegen implements Code
             op.vendorExtensions.put("x-java-import", operationImports);
 
             handleImplicitHeaders(op);
+            handleConstantParams(op);
         }
 
         return objs;
@@ -2052,6 +2060,10 @@ public abstract class AbstractJavaCodegen extends DefaultCodegen implements Code
         this.implicitHeadersRegex = implicitHeadersRegex;
     }
 
+    public void setAutosetConstants(boolean autosetConstants) {
+        this.autosetConstants = autosetConstants;
+    }
+
     public void setCamelCaseDollarSign(boolean camelCaseDollarSign) {
         this.camelCaseDollarSign = camelCaseDollarSign;
     }
@@ -2294,6 +2306,45 @@ public abstract class AbstractJavaCodegen extends DefaultCodegen implements Code
         operation.hasParams = !operation.allParams.isEmpty();
     }
 
+    /**
+     * This method removes all constant Query, Header and Cookie Params from allParams and sets them as constantParams in the CodegenOperation.
+     * The definition of constant is single valued required enum params.
+     * The constantParams in the the generated code should be hardcoded to the constantValue if autosetConstants feature is enabled.
+     *
+     * @param operation - operation to be processed
+     */
+    protected void handleConstantParams(CodegenOperation operation) {
+        if (!autosetConstants || operation.allParams.isEmpty()) {            
+            return;
+        }
+        final ArrayList<CodegenParameter> copy = new ArrayList<>(operation.allParams);
+        // Remove all params from Params, Non constant params will be added back later.
+        operation.allParams.clear();
+
+        // Finds all constant params, removes them from allParams and adds them to constant params.
+        // Also, adds back non constant params to allParams.
+        for (CodegenParameter p : copy) {
+            if (p.isEnum && p.required && p._enum != null && p._enum.size() == 1) {
+                // Add to constantParams for use in the code generation templates. 
+                operation.constantParams.add(p);
+                if(p.isQueryParam) {
+                    operation.queryParams.removeIf(param -> param.baseName.equals(p.baseName));
+                }
+                if(p.isHeaderParam) {
+                    operation.headerParams.removeIf(param -> param.baseName.equals(p.baseName));
+                }
+                if(p.isCookieParam) {
+                    operation.cookieParams.removeIf(param -> param.baseName.equals(p.baseName));
+                }
+                LOGGER.info("Update operation [{}]. Remove parameter [{}] because it can only have a fixed value of [{}]", operation.operationId, p.baseName, p._enum.get(0));
+            } else {
+                // Add back to allParams as the param is not a constant.
+                operation.allParams.add(p);
+            }
+        }
+        operation.hasParams = !operation.allParams.isEmpty();
+    }
+
     private boolean shouldBeImplicitHeader(CodegenParameter parameter) {
         return StringUtils.isNotBlank(implicitHeadersRegex) && parameter.baseName.matches(implicitHeadersRegex);
     }

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

@@ -1981,4 +1981,17 @@ public abstract class AbstractPythonCodegen extends DefaultCodegen implements Co
     public String toEnumDefaultValue(String value, String datatype) {
         return value;
     }
+
+    /**
+     * checks if the data should be classified as "string" in enum
+     * e.g. double in C# needs to be double-quoted (e.g. "2.8") by treating it as a string
+     * In the future, we may rename this function to "isEnumString"
+     *
+     * @param dataType data type
+     * @return true if it's a enum string
+     */
+    @Override
+    public boolean isDataTypeString(String dataType) {
+        return "str".equals(dataType);
+    }
 }

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

@@ -16,17 +16,9 @@
 
 package org.openapitools.codegen.languages;
 
-import static org.openapitools.codegen.utils.StringUtils.camelize;
-
 import java.io.File;
 import java.io.IOException;
-import java.util.ArrayList;
-import java.util.Collection;
-import java.util.Collections;
-import java.util.HashMap;
-import java.util.List;
-import java.util.Map;
-import java.util.Set;
+import java.util.*;
 
 import org.apache.commons.lang3.StringUtils;
 import org.openapitools.codegen.CliOption;
@@ -69,6 +61,8 @@ import io.swagger.v3.oas.models.parameters.Parameter;
 import io.swagger.v3.oas.models.parameters.RequestBody;
 import io.swagger.v3.oas.models.security.SecurityScheme;
 
+import static org.openapitools.codegen.utils.StringUtils.*;
+
 public abstract class AbstractPythonConnexionServerCodegen extends AbstractPythonCodegen implements CodegenConfig {
     private static class PythonBooleanSerializer extends JsonSerializer<Boolean> {
         @Override
@@ -178,7 +172,7 @@ public abstract class AbstractPythonConnexionServerCodegen extends AbstractPytho
         cliOptions.add(new CliOption(USE_PYTHON_SRC_ROOT_IN_IMPORTS, "include pythonSrcRoot in import namespaces.").
                 defaultValue("false"));
         cliOptions.add(new CliOption(MOVE_TESTS_UNDER_PYTHON_SRC_ROOT, "generates test under the pythonSrcRoot folder.")
-            .defaultValue("false"));
+                .defaultValue("false"));
     }
 
     protected void addSupportingFiles() {
@@ -333,7 +327,6 @@ public abstract class AbstractPythonConnexionServerCodegen extends AbstractPytho
     }
 
 
-
     @Override
     public String toApiTestFilename(String name) {
         return "test_" + toApiFilename(name);
@@ -636,12 +629,6 @@ public abstract class AbstractPythonConnexionServerCodegen extends AbstractPytho
         postProcessPattern(property.pattern, property.vendorExtensions);
     }
 
-    @Override
-    public ModelsMap postProcessModels(ModelsMap objs) {
-        // process enum in models
-        return postProcessModelsEnum(objs);
-    }
-
     @Override
     public Map<String, ModelsMap> postProcessAllModels(Map<String, ModelsMap> objs) {
         Map<String, ModelsMap> result = super.postProcessAllModels(objs);

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

@@ -464,20 +464,6 @@ public class PythonClientCodegen extends AbstractPythonCodegen implements Codege
         }
     }
 
-
-    /**
-     * checks if the data should be classified as "string" in enum
-     * e.g. double in C# needs to be double-quoted (e.g. "2.8") by treating it as a string
-     * In the future, we may rename this function to "isEnumString"
-     *
-     * @param dataType data type
-     * @return true if it's a enum string
-     */
-    @Override
-    public boolean isDataTypeString(String dataType) {
-        return "str".equals(dataType);
-    }
-
     @Override
     public String escapeReservedWord(String name) {
         if (this.reservedWordsMappings().containsKey(name)) {

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

@@ -438,6 +438,10 @@ public class ModelUtils {
      * @return true if the specified schema is an Object schema.
      */
     public static boolean isObjectSchema(Schema schema) {
+        if (schema == null) {
+            return false;
+        }
+
         return (schema instanceof ObjectSchema) ||
                 // must not be a map
                 (SchemaTypeUtil.OBJECT_TYPE.equals(schema.getType()) && !(schema instanceof MapSchema)) ||
@@ -549,6 +553,10 @@ public class ModelUtils {
      * @return true if the specified schema is a Map schema.
      */
     public static boolean isMapSchema(Schema schema) {
+        if (schema == null) {
+            return false;
+        }
+
         // additionalProperties explicitly set to false
         if (schema.getAdditionalProperties() instanceof Boolean && Boolean.FALSE.equals(schema.getAdditionalProperties())) {
             return false;
@@ -1858,6 +1866,10 @@ public class ModelUtils {
      * @return true if the schema contains oneOf but no properties/allOf/anyOf defined.
      */
     public static boolean isOneOf(Schema schema) {
+        if (schema == null) {
+            return false;
+        }
+
         if (hasOneOf(schema) && (schema.getProperties() == null || schema.getProperties().isEmpty()) &&
                 (schema.getAllOf() == null || schema.getAllOf().isEmpty()) &&
                 (schema.getAnyOf() == null || schema.getAnyOf().isEmpty())) {
@@ -1875,7 +1887,7 @@ public class ModelUtils {
      * @return true if allOf is not empty
      */
     public static boolean hasOneOf(Schema schema) {
-        if (schema.getOneOf() != null && !schema.getOneOf().isEmpty()) {
+        if (schema != null && schema.getOneOf() != null && !schema.getOneOf().isEmpty()) {
             return true;
         }
 
@@ -1890,6 +1902,10 @@ public class ModelUtils {
      * @return true if the schema contains oneOf but no properties/allOf/anyOf defined.
      */
     public static boolean isAnyOf(Schema schema) {
+        if (schema == null) {
+            return false;
+        }
+
         if (hasAnyOf(schema) && (schema.getProperties() == null || schema.getProperties().isEmpty()) &&
                 (schema.getAllOf() == null || schema.getAllOf().isEmpty()) &&
                 (schema.getOneOf() == null || schema.getOneOf().isEmpty())) {
@@ -1907,7 +1923,7 @@ public class ModelUtils {
      * @return true if anyOf is not empty
      */
     public static boolean hasAnyOf(Schema schema) {
-        if (schema.getAnyOf() != null && !schema.getAnyOf().isEmpty()) {
+        if (schema != null && schema.getAnyOf() != null && !schema.getAnyOf().isEmpty()) {
             return true;
         }
 

modules/openapi-generator/src/main/resources/Java/libraries/okhttp-gson/api.mustache

@@ -172,18 +172,39 @@ public class {{classname}} {
         }
 
         {{/queryParams}}
+        {{#constantParams}}
+        {{#isQueryParam}}
+        // Set client side default value of Query Param "{{baseName}}".
+        localVarCollectionQueryParams.add(new Pair("{{baseName}}", {{#_enum}}"{{{.}}}"{{/_enum}}));
+
+        {{/isQueryParam}}
+        {{/constantParams}}
         {{#headerParams}}
         if ({{paramName}} != null) {
             localVarHeaderParams.put("{{baseName}}", localVarApiClient.parameterToString({{paramName}}));
         }
 
         {{/headerParams}}
+        {{#constantParams}}
+        {{#isHeaderParam}}
+        // Set client side default value of Header Param "{{baseName}}".
+        localVarHeaderParams.put("{{baseName}}", {{#_enum}}"{{{.}}}"{{/_enum}});
+
+        {{/isHeaderParam}}
+        {{/constantParams}}
         {{#cookieParams}}
         if ({{paramName}} != null) {
             localVarCookieParams.put("{{baseName}}", localVarApiClient.parameterToString({{paramName}}));
         }
 
         {{/cookieParams}}
+        {{#constantParams}}
+        {{#isCookieParam}}
+        // Set client side default value of Cookie Param "{{baseName}}".
+        localVarCookieParams.put("{{baseName}}", {{#_enum}}"{{{.}}}"{{/_enum}});
+
+        {{/isCookieParam}}
+        {{/constantParams}}
         {{/dynamicOperations}}
         {{#dynamicOperations}}
         localVarPath = localVarApiClient.fillParametersFromOperation(operation, paramMap, localVarPath, localVarQueryParams, localVarCollectionQueryParams, localVarHeaderParams, localVarCookieParams);

modules/openapi-generator/src/main/resources/python-flask/model.mustache

@@ -29,7 +29,7 @@ class {{classname}}(Model):
     allowed enum values
     """
 {{#enumVars}}
-    {{name}} = {{{value}}}{{^-last}}
+    {{{name}}} = {{{value}}}{{^-last}}
 {{/-last}}
 {{/enumVars}}
 {{/allowableValues}}

modules/openapi-generator/src/main/resources/swift5/libraries/urlsession/URLSessionImplementations.mustache

@@ -46,15 +46,6 @@ private var credentialStore = SynchronizedDictionary<Int, URLCredential>()
      */
     {{#nonPublicApi}}internal{{/nonPublicApi}}{{^nonPublicApi}}public{{/nonPublicApi}} var taskDidReceiveChallenge: {{projectName}}APIChallengeHandler?
 
-    /**
-     May be assigned if you want to do any of those things:
-     - control the task completion
-     - intercept and handle errors like authorization
-     - retry the request.
-     */
-    @available(*, unavailable, message: "Please override execute() method to intercept and handle errors like authorization or retry the request. Check the Wiki for more info. https://github.com/OpenAPITools/openapi-generator/wiki/FAQ#how-do-i-implement-bearer-token-authentication-with-urlsession-on-the-swift-api-client")
-    {{#nonPublicApi}}internal{{/nonPublicApi}}{{^nonPublicApi}}public{{/nonPublicApi}} var taskCompletionShouldRetry: ((Data?, URLResponse?, Error?, @escaping (Bool) -> Void) -> Void)?
-
     required {{#nonPublicApi}}internal{{/nonPublicApi}}{{^nonPublicApi}}public{{/nonPublicApi}} init(method: String, URLString: String, parameters: [String: Any]?, headers: [String: String] = [:], requiresAuthentication: Bool) {
         super.init(method: method, URLString: URLString, parameters: parameters, headers: headers, requiresAuthentication: requiresAuthentication)
     }

modules/openapi-generator/src/test/resources/2_0/python-flask/petstore.yaml

@@ -0,0 +1,703 @@
+swagger: '2.0'
+info:
+  description: 'This is a sample server Petstore server. For this sample, you can use the api key `special-key` to test the authorization filters.'
+  version: 1.0.0
+  title: OpenAPI Petstore
+  license:
+    name: Apache-2.0
+    url: 'https://www.apache.org/licenses/LICENSE-2.0.html'
+host: petstore.swagger.io
+basePath: /v2
+tags:
+  - name: pet
+    description: Everything about your Pets
+  - name: store
+    description: Access to Petstore orders
+  - name: user
+    description: Operations about user
+schemes:
+  - http
+paths:
+  /pet:
+    post:
+      tags:
+        - pet
+      summary: Add a new pet to the store
+      description: ''
+      operationId: addPet
+      consumes:
+        - application/json
+        - application/xml
+      produces:
+        - application/xml
+        - application/json
+      parameters:
+        - in: body
+          name: body
+          description: Pet object that needs to be added to the store
+          required: true
+          schema:
+            $ref: '#/definitions/Pet'
+      responses:
+        '405':
+          description: Invalid input
+      security:
+        - petstore_auth:
+            - 'write:pets'
+            - 'read:pets'
+    put:
+      tags:
+        - pet
+      summary: Update an existing pet
+      description: ''
+      operationId: updatePet
+      consumes:
+        - application/json
+        - application/xml
+      produces:
+        - application/xml
+        - application/json
+      parameters:
+        - in: body
+          name: body
+          description: Pet object that needs to be added to the store
+          required: true
+          schema:
+            $ref: '#/definitions/Pet'
+      responses:
+        '400':
+          description: Invalid ID supplied
+        '404':
+          description: Pet not found
+        '405':
+          description: Validation exception
+      security:
+        - petstore_auth:
+            - 'write:pets'
+            - 'read:pets'
+  /pet/findByStatus:
+    get:
+      tags:
+        - pet
+      summary: Finds Pets by status
+      description: Multiple status values can be provided with comma separated strings
+      operationId: findPetsByStatus
+      produces:
+        - application/xml
+        - application/json
+      parameters:
+        - name: status
+          in: query
+          description: Status values that need to be considered for filter
+          required: true
+          type: array
+          items:
+            type: string
+            enum:
+              - available
+              - pending
+              - sold
+            default: available
+          collectionFormat: csv
+      responses:
+        '200':
+          description: successful operation
+          schema:
+            type: array
+            items:
+              $ref: '#/definitions/Pet'
+        '400':
+          description: Invalid status value
+      security:
+        - petstore_auth:
+            - 'write:pets'
+            - 'read:pets'
+  /pet/findByTags:
+    get:
+      tags:
+        - pet
+      summary: Finds Pets by tags
+      description: 'Multiple tags can be provided with comma separated strings. Use tag1, tag2, tag3 for testing.'
+      operationId: findPetsByTags
+      produces:
+        - application/xml
+        - application/json
+      parameters:
+        - name: tags
+          in: query
+          description: Tags to filter by
+          required: true
+          type: array
+          items:
+            type: string
+          collectionFormat: csv
+      responses:
+        '200':
+          description: successful operation
+          schema:
+            type: array
+            items:
+              $ref: '#/definitions/Pet'
+        '400':
+          description: Invalid tag value
+      security:
+        - petstore_auth:
+            - 'write:pets'
+            - 'read:pets'
+      deprecated: true
+  '/pet/{petId}':
+    get:
+      tags:
+        - pet
+      summary: Find pet by ID
+      description: Returns a single pet
+      operationId: getPetById
+      produces:
+        - application/xml
+        - application/json
+      parameters:
+        - name: petId
+          in: path
+          description: ID of pet to return
+          required: true
+          type: integer
+          format: int64
+      responses:
+        '200':
+          description: successful operation
+          schema:
+            $ref: '#/definitions/Pet'
+        '400':
+          description: Invalid ID supplied
+        '404':
+          description: Pet not found
+      security:
+        - api_key: []
+    post:
+      tags:
+        - pet
+      summary: Updates a pet in the store with form data
+      description: ''
+      operationId: updatePetWithForm
+      consumes:
+        - application/x-www-form-urlencoded
+      produces:
+        - application/xml
+        - application/json
+      parameters:
+        - name: petId
+          in: path
+          description: ID of pet that needs to be updated
+          required: true
+          type: integer
+          format: int64
+        - name: name
+          in: formData
+          description: Updated name of the pet
+          required: false
+          type: string
+        - name: status
+          in: formData
+          description: Updated status of the pet
+          required: false
+          type: string
+      responses:
+        '405':
+          description: Invalid input
+      security:
+        - petstore_auth:
+            - 'write:pets'
+            - 'read:pets'
+    delete:
+      tags:
+        - pet
+      summary: Deletes a pet
+      description: ''
+      operationId: deletePet
+      produces:
+        - application/xml
+        - application/json
+      parameters:
+        - name: api_key
+          in: header
+          required: false
+          type: string
+        - name: petId
+          in: path
+          description: Pet id to delete
+          required: true
+          type: integer
+          format: int64
+      responses:
+        '400':
+          description: Invalid pet value
+      security:
+        - petstore_auth:
+            - 'write:pets'
+            - 'read:pets'
+  '/pet/{petId}/uploadImage':
+    post:
+      tags:
+        - pet
+      summary: uploads an image
+      description: ''
+      operationId: uploadFile
+      consumes:
+        - multipart/form-data
+      produces:
+        - application/json
+      parameters:
+        - name: petId
+          in: path
+          description: ID of pet to update
+          required: true
+          type: integer
+          format: int64
+        - name: additionalMetadata
+          in: formData
+          description: Additional data to pass to server
+          required: false
+          type: string
+        - name: file
+          in: formData
+          description: file to upload
+          required: false
+          type: file
+      responses:
+        '200':
+          description: successful operation
+          schema:
+            $ref: '#/definitions/ApiResponse'
+      security:
+        - petstore_auth:
+            - 'write:pets'
+            - 'read:pets'
+  /store/inventory:
+    get:
+      tags:
+        - store
+      summary: Returns pet inventories by status
+      description: Returns a map of status codes to quantities
+      operationId: getInventory
+      produces:
+        - application/json
+      parameters: []
+      responses:
+        '200':
+          description: successful operation
+          schema:
+            type: object
+            additionalProperties:
+              type: integer
+              format: int32
+      security:
+        - api_key: []
+  /store/order:
+    post:
+      tags:
+        - store
+      summary: Place an order for a pet
+      description: ''
+      operationId: placeOrder
+      produces:
+        - application/xml
+        - application/json
+      parameters:
+        - in: body
+          name: body
+          description: order placed for purchasing the pet
+          required: true
+          schema:
+            $ref: '#/definitions/Order'
+      responses:
+        '200':
+          description: successful operation
+          schema:
+            $ref: '#/definitions/Order'
+        '400':
+          description: Invalid Order
+  '/store/order/{orderId}':
+    get:
+      tags:
+        - store
+      summary: Find purchase order by ID
+      description: 'For valid response try integer IDs with value <= 5 or > 10. Other values will generate exceptions'
+      operationId: getOrderById
+      produces:
+        - application/xml
+        - application/json
+      parameters:
+        - name: orderId
+          in: path
+          description: ID of pet that needs to be fetched
+          required: true
+          type: integer
+          maximum: 5
+          minimum: 1
+          format: int64
+      responses:
+        '200':
+          description: successful operation
+          schema:
+            $ref: '#/definitions/Order'
+        '400':
+          description: Invalid ID supplied
+        '404':
+          description: Order not found
+    delete:
+      tags:
+        - store
+      summary: Delete purchase order by ID
+      description: For valid response try integer IDs with value < 1000. Anything above 1000 or nonintegers will generate API errors
+      operationId: deleteOrder
+      produces:
+        - application/xml
+        - application/json
+      parameters:
+        - name: orderId
+          in: path
+          description: ID of the order that needs to be deleted
+          required: true
+          type: string
+      responses:
+        '400':
+          description: Invalid ID supplied
+        '404':
+          description: Order not found
+  /user:
+    post:
+      tags:
+        - user
+      summary: Create user
+      description: This can only be done by the logged in user.
+      operationId: createUser
+      produces:
+        - application/xml
+        - application/json
+      parameters:
+        - in: body
+          name: body
+          description: Created user object
+          required: true
+          schema:
+            $ref: '#/definitions/User'
+      responses:
+        default:
+          description: successful operation
+  /user/createWithArray:
+    post:
+      tags:
+        - user
+      summary: Creates list of users with given input array
+      description: ''
+      operationId: createUsersWithArrayInput
+      produces:
+        - application/xml
+        - application/json
+      parameters:
+        - in: body
+          name: body
+          description: List of user object
+          required: true
+          schema:
+            type: array
+            items:
+              $ref: '#/definitions/User'
+      responses:
+        default:
+          description: successful operation
+  /user/createWithList:
+    post:
+      tags:
+        - user
+      summary: Creates list of users with given input array
+      description: ''
+      operationId: createUsersWithListInput
+      produces:
+        - application/xml
+        - application/json
+      parameters:
+        - in: body
+          name: body
+          description: List of user object
+          required: true
+          schema:
+            type: array
+            items:
+              $ref: '#/definitions/User'
+      responses:
+        default:
+          description: successful operation
+  /user/login:
+    get:
+      tags:
+        - user
+      summary: Logs user into the system
+      description: ''
+      operationId: loginUser
+      produces:
+        - application/xml
+        - application/json
+      parameters:
+        - name: username
+          in: query
+          description: The user name for login
+          required: true
+          type: string
+        - name: password
+          in: query
+          description: The password for login in clear text
+          required: true
+          type: string
+      responses:
+        '200':
+          description: successful operation
+          schema:
+            type: string
+          headers:
+            X-Rate-Limit:
+              type: integer
+              format: int32
+              description: calls per hour allowed by the user
+            X-Expires-After:
+              type: string
+              format: date-time
+              description: date in UTC when token expires
+        '400':
+          description: Invalid username/password supplied
+  /user/logout:
+    get:
+      tags:
+        - user
+      summary: Logs out current logged in user session
+      description: ''
+      operationId: logoutUser
+      produces:
+        - application/xml
+        - application/json
+      parameters: []
+      responses:
+        default:
+          description: successful operation
+  '/user/{username}':
+    get:
+      tags:
+        - user
+      summary: Get user by user name
+      description: ''
+      operationId: getUserByName
+      produces:
+        - application/xml
+        - application/json
+      parameters:
+        - name: username
+          in: path
+          description: 'The name that needs to be fetched. Use user1 for testing.'
+          required: true
+          type: string
+      responses:
+        '200':
+          description: successful operation
+          schema:
+            $ref: '#/definitions/User'
+        '400':
+          description: Invalid username supplied
+        '404':
+          description: User not found
+    put:
+      tags:
+        - user
+      summary: Updated user
+      description: This can only be done by the logged in user.
+      operationId: updateUser
+      produces:
+        - application/xml
+        - application/json
+      parameters:
+        - name: username
+          in: path
+          description: name that need to be deleted
+          required: true
+          type: string
+        - in: body
+          name: body
+          description: Updated user object
+          required: true
+          schema:
+            $ref: '#/definitions/User'
+      responses:
+        '400':
+          description: Invalid user supplied
+        '404':
+          description: User not found
+    delete:
+      tags:
+        - user
+      summary: Delete user
+      description: This can only be done by the logged in user.
+      operationId: deleteUser
+      produces:
+        - application/xml
+        - application/json
+      parameters:
+        - name: username
+          in: path
+          description: The name that needs to be deleted
+          required: true
+          type: string
+      responses:
+        '400':
+          description: Invalid username supplied
+        '404':
+          description: User not found
+securityDefinitions:
+  petstore_auth:
+    type: oauth2
+    authorizationUrl: 'http://petstore.swagger.io/api/oauth/dialog'
+    flow: implicit
+    scopes:
+      'write:pets': modify pets in your account
+      'read:pets': read your pets
+  api_key:
+    type: apiKey
+    name: api_key
+    in: header
+definitions:
+  Order:
+    title: Pet Order
+    description: An order for a pets from the pet store
+    type: object
+    properties:
+      id:
+        type: integer
+        format: int64
+      petId:
+        type: integer
+        format: int64
+      quantity:
+        type: integer
+        format: int32
+      shipDate:
+        type: string
+        format: date-time
+      status:
+        type: string
+        description: Order Status
+        enum:
+          - placed
+          - approved
+          - delivered
+      complete:
+        type: boolean
+        default: false
+    xml:
+      name: Order
+  Category:
+    title: Pet category
+    description: A category for a pet
+    type: object
+    properties:
+      id:
+        type: integer
+        format: int64
+      name:
+        type: string
+    xml:
+      name: Category
+  User:
+    title: a User
+    description: A User who is purchasing from the pet store
+    type: object
+    properties:
+      id:
+        type: integer
+        format: int64
+      username:
+        type: string
+      firstName:
+        type: string
+      lastName:
+        type: string
+      email:
+        type: string
+      password:
+        type: string
+      phone:
+        type: string
+      userStatus:
+        type: integer
+        format: int32
+        description: User Status
+    xml:
+      name: User
+  Tag:
+    title: Pet Tag
+    description: A tag for a pet
+    type: object
+    properties:
+      id:
+        type: integer
+        format: int64
+      name:
+        type: string
+    xml:
+      name: Tag
+  Pet:
+    title: a Pet
+    description: A pet for sale in the pet store
+    type: object
+    required:
+      - name
+      - photoUrls
+    properties:
+      id:
+        type: integer
+        format: int64
+      category:
+        $ref: '#/definitions/Category'
+      name:
+        type: string
+        example: doggie
+      photoUrls:
+        type: array
+        xml:
+          name: photoUrl
+          wrapped: true
+        items:
+          type: string
+      tags:
+        type: array
+        xml:
+          name: tag
+          wrapped: true
+        items:
+          $ref: '#/definitions/Tag'
+      status:
+        type: string
+        description: pet status in the store
+        enum:
+          - available
+          - pending
+          - sold
+    xml:
+      name: Pet
+  ApiResponse:
+    title: An uploaded response
+    description: Describes the result of uploading an image resource
+    type: object
+    properties:
+      code:
+        type: integer
+        format: int32
+      type:
+        type: string
+      message:
+        type: string
+  EnumModel:
+    enum:
+      - available>
+      - pending<
+      - sold
+      - 1
+      - 2
+    type: string

modules/openapi-generator/src/test/resources/3_0/java/autoset_constant.yaml

@@ -0,0 +1,42 @@
+openapi: 3.0.3
+info:
+  title: Example Hello API
+  description: ''
+  version: v1
+servers:
+  - url: http://localhost
+    description: Global Endpoint
+paths:
+  /v1/hello/{name}:
+    get:
+      tags:
+        - hello_example
+      operationId: Hello
+      description: Say Hello
+      parameters:
+        - name: X-CUSTOM_CONSTANT_HEADER
+          in: header
+          required: true
+          schema:
+            type: string
+            enum:
+            - CONSTANT_VALUE
+        - name: name
+          in: path
+          required: true
+          schema:
+            type: string
+      responses:
+        default:
+          description: Successful operation
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/HelloResponse'
+components:
+  schemas:
+    HelloResponse:
+      type: object
+      properties:
+        message:
+          type: string

samples/client/petstore/swift5/anycodableLibrary/PetstoreClient/Classes/OpenAPIs/URLSessionImplementations.swift

@@ -46,15 +46,6 @@ open class URLSessionRequestBuilder<T>: RequestBuilder<T> {
      */
     public var taskDidReceiveChallenge: PetstoreClientAPIChallengeHandler?
 
-    /**
-     May be assigned if you want to do any of those things:
-     - control the task completion
-     - intercept and handle errors like authorization
-     - retry the request.
-     */
-    @available(*, unavailable, message: "Please override execute() method to intercept and handle errors like authorization or retry the request. Check the Wiki for more info. https://github.com/OpenAPITools/openapi-generator/wiki/FAQ#how-do-i-implement-bearer-token-authentication-with-urlsession-on-the-swift-api-client")
-    public var taskCompletionShouldRetry: ((Data?, URLResponse?, Error?, @escaping (Bool) -> Void) -> Void)?
-
     required public init(method: String, URLString: String, parameters: [String: Any]?, headers: [String: String] = [:], requiresAuthentication: Bool) {
         super.init(method: method, URLString: URLString, parameters: parameters, headers: headers, requiresAuthentication: requiresAuthentication)
     }

samples/client/petstore/swift5/asyncAwaitLibrary/PetstoreClient/Classes/OpenAPIs/URLSessionImplementations.swift

@@ -46,15 +46,6 @@ open class URLSessionRequestBuilder<T>: RequestBuilder<T> {
      */
     public var taskDidReceiveChallenge: PetstoreClientAPIChallengeHandler?
 
-    /**
-     May be assigned if you want to do any of those things:
-     - control the task completion
-     - intercept and handle errors like authorization
-     - retry the request.
-     */
-    @available(*, unavailable, message: "Please override execute() method to intercept and handle errors like authorization or retry the request. Check the Wiki for more info. https://github.com/OpenAPITools/openapi-generator/wiki/FAQ#how-do-i-implement-bearer-token-authentication-with-urlsession-on-the-swift-api-client")
-    public var taskCompletionShouldRetry: ((Data?, URLResponse?, Error?, @escaping (Bool) -> Void) -> Void)?
-
     required public init(method: String, URLString: String, parameters: [String: Any]?, headers: [String: String] = [:], requiresAuthentication: Bool) {
         super.init(method: method, URLString: URLString, parameters: parameters, headers: headers, requiresAuthentication: requiresAuthentication)
     }

samples/client/petstore/swift5/combineLibrary/PetstoreClient/Classes/OpenAPIs/URLSessionImplementations.swift

@@ -46,15 +46,6 @@ open class URLSessionRequestBuilder<T>: RequestBuilder<T> {
      */
     public var taskDidReceiveChallenge: PetstoreClientAPIChallengeHandler?
 
-    /**
-     May be assigned if you want to do any of those things:
-     - control the task completion
-     - intercept and handle errors like authorization
-     - retry the request.
-     */
-    @available(*, unavailable, message: "Please override execute() method to intercept and handle errors like authorization or retry the request. Check the Wiki for more info. https://github.com/OpenAPITools/openapi-generator/wiki/FAQ#how-do-i-implement-bearer-token-authentication-with-urlsession-on-the-swift-api-client")
-    public var taskCompletionShouldRetry: ((Data?, URLResponse?, Error?, @escaping (Bool) -> Void) -> Void)?
-
     required public init(method: String, URLString: String, parameters: [String: Any]?, headers: [String: String] = [:], requiresAuthentication: Bool) {
         super.init(method: method, URLString: URLString, parameters: parameters, headers: headers, requiresAuthentication: requiresAuthentication)
     }

samples/client/petstore/swift5/default/PetstoreClient/Classes/OpenAPIs/URLSessionImplementations.swift

@@ -46,15 +46,6 @@ open class URLSessionRequestBuilder<T>: RequestBuilder<T> {
      */
     public var taskDidReceiveChallenge: PetstoreClientAPIChallengeHandler?
 
-    /**
-     May be assigned if you want to do any of those things:
-     - control the task completion
-     - intercept and handle errors like authorization
-     - retry the request.
-     */
-    @available(*, unavailable, message: "Please override execute() method to intercept and handle errors like authorization or retry the request. Check the Wiki for more info. https://github.com/OpenAPITools/openapi-generator/wiki/FAQ#how-do-i-implement-bearer-token-authentication-with-urlsession-on-the-swift-api-client")
-    public var taskCompletionShouldRetry: ((Data?, URLResponse?, Error?, @escaping (Bool) -> Void) -> Void)?
-
     required public init(method: String, URLString: String, parameters: [String: Any]?, headers: [String: String] = [:], requiresAuthentication: Bool) {
         super.init(method: method, URLString: URLString, parameters: parameters, headers: headers, requiresAuthentication: requiresAuthentication)
     }

samples/client/petstore/swift5/deprecated/PetstoreClient/Classes/OpenAPIs/URLSessionImplementations.swift

@@ -46,15 +46,6 @@ open class URLSessionRequestBuilder<T>: RequestBuilder<T> {
      */
     public var taskDidReceiveChallenge: PetstoreClientAPIChallengeHandler?
 
-    /**
-     May be assigned if you want to do any of those things:
-     - control the task completion
-     - intercept and handle errors like authorization
-     - retry the request.
-     */
-    @available(*, unavailable, message: "Please override execute() method to intercept and handle errors like authorization or retry the request. Check the Wiki for more info. https://github.com/OpenAPITools/openapi-generator/wiki/FAQ#how-do-i-implement-bearer-token-authentication-with-urlsession-on-the-swift-api-client")
-    public var taskCompletionShouldRetry: ((Data?, URLResponse?, Error?, @escaping (Bool) -> Void) -> Void)?
-
     required public init(method: String, URLString: String, parameters: [String: Any]?, headers: [String: String] = [:], requiresAuthentication: Bool) {
         super.init(method: method, URLString: URLString, parameters: parameters, headers: headers, requiresAuthentication: requiresAuthentication)
     }

samples/client/petstore/swift5/frozenEnums/PetstoreClient/Classes/OpenAPIs/URLSessionImplementations.swift

@@ -46,15 +46,6 @@ open class URLSessionRequestBuilder<T>: RequestBuilder<T> {
      */
     public var taskDidReceiveChallenge: PetstoreClientAPIChallengeHandler?
 
-    /**
-     May be assigned if you want to do any of those things:
-     - control the task completion
-     - intercept and handle errors like authorization
-     - retry the request.
-     */
-    @available(*, unavailable, message: "Please override execute() method to intercept and handle errors like authorization or retry the request. Check the Wiki for more info. https://github.com/OpenAPITools/openapi-generator/wiki/FAQ#how-do-i-implement-bearer-token-authentication-with-urlsession-on-the-swift-api-client")
-    public var taskCompletionShouldRetry: ((Data?, URLResponse?, Error?, @escaping (Bool) -> Void) -> Void)?
-
     required public init(method: String, URLString: String, parameters: [String: Any]?, headers: [String: String] = [:], requiresAuthentication: Bool) {
         super.init(method: method, URLString: URLString, parameters: parameters, headers: headers, requiresAuthentication: requiresAuthentication)
     }

samples/client/petstore/swift5/nonPublicApi/PetstoreClient/Classes/OpenAPIs/URLSessionImplementations.swift

@@ -46,15 +46,6 @@ internal class URLSessionRequestBuilder<T>: RequestBuilder<T> {
      */
     internal var taskDidReceiveChallenge: PetstoreClientAPIChallengeHandler?
 
-    /**
-     May be assigned if you want to do any of those things:
-     - control the task completion
-     - intercept and handle errors like authorization
-     - retry the request.
-     */
-    @available(*, unavailable, message: "Please override execute() method to intercept and handle errors like authorization or retry the request. Check the Wiki for more info. https://github.com/OpenAPITools/openapi-generator/wiki/FAQ#how-do-i-implement-bearer-token-authentication-with-urlsession-on-the-swift-api-client")
-    internal var taskCompletionShouldRetry: ((Data?, URLResponse?, Error?, @escaping (Bool) -> Void) -> Void)?
-
     required internal init(method: String, URLString: String, parameters: [String: Any]?, headers: [String: String] = [:], requiresAuthentication: Bool) {
         super.init(method: method, URLString: URLString, parameters: parameters, headers: headers, requiresAuthentication: requiresAuthentication)
     }

samples/client/petstore/swift5/objcCompatible/PetstoreClient/Classes/OpenAPIs/URLSessionImplementations.swift

@@ -46,15 +46,6 @@ open class URLSessionRequestBuilder<T>: RequestBuilder<T> {
      */
     public var taskDidReceiveChallenge: PetstoreClientAPIChallengeHandler?
 
-    /**
-     May be assigned if you want to do any of those things:
-     - control the task completion
-     - intercept and handle errors like authorization
-     - retry the request.
-     */
-    @available(*, unavailable, message: "Please override execute() method to intercept and handle errors like authorization or retry the request. Check the Wiki for more info. https://github.com/OpenAPITools/openapi-generator/wiki/FAQ#how-do-i-implement-bearer-token-authentication-with-urlsession-on-the-swift-api-client")
-    public var taskCompletionShouldRetry: ((Data?, URLResponse?, Error?, @escaping (Bool) -> Void) -> Void)?
-
     required public init(method: String, URLString: String, parameters: [String: Any]?, headers: [String: String] = [:], requiresAuthentication: Bool) {
         super.init(method: method, URLString: URLString, parameters: parameters, headers: headers, requiresAuthentication: requiresAuthentication)
     }

samples/client/petstore/swift5/oneOf/PetstoreClient/Classes/OpenAPIs/URLSessionImplementations.swift

@@ -46,15 +46,6 @@ open class URLSessionRequestBuilder<T>: RequestBuilder<T> {
      */
     public var taskDidReceiveChallenge: PetstoreClientAPIChallengeHandler?
 
-    /**
-     May be assigned if you want to do any of those things:
-     - control the task completion
-     - intercept and handle errors like authorization
-     - retry the request.
-     */
-    @available(*, unavailable, message: "Please override execute() method to intercept and handle errors like authorization or retry the request. Check the Wiki for more info. https://github.com/OpenAPITools/openapi-generator/wiki/FAQ#how-do-i-implement-bearer-token-authentication-with-urlsession-on-the-swift-api-client")
-    public var taskCompletionShouldRetry: ((Data?, URLResponse?, Error?, @escaping (Bool) -> Void) -> Void)?
-
     required public init(method: String, URLString: String, parameters: [String: Any]?, headers: [String: String] = [:], requiresAuthentication: Bool) {
         super.init(method: method, URLString: URLString, parameters: parameters, headers: headers, requiresAuthentication: requiresAuthentication)
     }

samples/client/petstore/swift5/promisekitLibrary/PetstoreClient/Classes/OpenAPIs/URLSessionImplementations.swift

@@ -46,15 +46,6 @@ open class URLSessionRequestBuilder<T>: RequestBuilder<T> {
      */
     public var taskDidReceiveChallenge: PetstoreClientAPIChallengeHandler?
 
-    /**
-     May be assigned if you want to do any of those things:
-     - control the task completion
-     - intercept and handle errors like authorization
-     - retry the request.
-     */
-    @available(*, unavailable, message: "Please override execute() method to intercept and handle errors like authorization or retry the request. Check the Wiki for more info. https://github.com/OpenAPITools/openapi-generator/wiki/FAQ#how-do-i-implement-bearer-token-authentication-with-urlsession-on-the-swift-api-client")
-    public var taskCompletionShouldRetry: ((Data?, URLResponse?, Error?, @escaping (Bool) -> Void) -> Void)?
-
     required public init(method: String, URLString: String, parameters: [String: Any]?, headers: [String: String] = [:], requiresAuthentication: Bool) {
         super.init(method: method, URLString: URLString, parameters: parameters, headers: headers, requiresAuthentication: requiresAuthentication)
     }

samples/client/petstore/swift5/readonlyProperties/PetstoreClient/Classes/OpenAPIs/URLSessionImplementations.swift

@@ -46,15 +46,6 @@ open class URLSessionRequestBuilder<T>: RequestBuilder<T> {
      */
     public var taskDidReceiveChallenge: PetstoreClientAPIChallengeHandler?
 
-    /**
-     May be assigned if you want to do any of those things:
-     - control the task completion
-     - intercept and handle errors like authorization
-     - retry the request.
-     */
-    @available(*, unavailable, message: "Please override execute() method to intercept and handle errors like authorization or retry the request. Check the Wiki for more info. https://github.com/OpenAPITools/openapi-generator/wiki/FAQ#how-do-i-implement-bearer-token-authentication-with-urlsession-on-the-swift-api-client")
-    public var taskCompletionShouldRetry: ((Data?, URLResponse?, Error?, @escaping (Bool) -> Void) -> Void)?
-
     required public init(method: String, URLString: String, parameters: [String: Any]?, headers: [String: String] = [:], requiresAuthentication: Bool) {
         super.init(method: method, URLString: URLString, parameters: parameters, headers: headers, requiresAuthentication: requiresAuthentication)
     }

samples/client/petstore/swift5/resultLibrary/PetstoreClient/Classes/OpenAPIs/URLSessionImplementations.swift

@@ -46,15 +46,6 @@ open class URLSessionRequestBuilder<T>: RequestBuilder<T> {
      */
     public var taskDidReceiveChallenge: PetstoreClientAPIChallengeHandler?
 
-    /**
-     May be assigned if you want to do any of those things:
-     - control the task completion
-     - intercept and handle errors like authorization
-     - retry the request.
-     */
-    @available(*, unavailable, message: "Please override execute() method to intercept and handle errors like authorization or retry the request. Check the Wiki for more info. https://github.com/OpenAPITools/openapi-generator/wiki/FAQ#how-do-i-implement-bearer-token-authentication-with-urlsession-on-the-swift-api-client")
-    public var taskCompletionShouldRetry: ((Data?, URLResponse?, Error?, @escaping (Bool) -> Void) -> Void)?
-
     required public init(method: String, URLString: String, parameters: [String: Any]?, headers: [String: String] = [:], requiresAuthentication: Bool) {
         super.init(method: method, URLString: URLString, parameters: parameters, headers: headers, requiresAuthentication: requiresAuthentication)
     }

samples/client/petstore/swift5/rxswiftLibrary/PetstoreClient/Classes/OpenAPIs/URLSessionImplementations.swift

@@ -46,15 +46,6 @@ open class URLSessionRequestBuilder<T>: RequestBuilder<T> {
      */
     public var taskDidReceiveChallenge: PetstoreClientAPIChallengeHandler?
 
-    /**
-     May be assigned if you want to do any of those things:
-     - control the task completion
-     - intercept and handle errors like authorization
-     - retry the request.
-     */
-    @available(*, unavailable, message: "Please override execute() method to intercept and handle errors like authorization or retry the request. Check the Wiki for more info. https://github.com/OpenAPITools/openapi-generator/wiki/FAQ#how-do-i-implement-bearer-token-authentication-with-urlsession-on-the-swift-api-client")
-    public var taskCompletionShouldRetry: ((Data?, URLResponse?, Error?, @escaping (Bool) -> Void) -> Void)?
-
     required public init(method: String, URLString: String, parameters: [String: Any]?, headers: [String: String] = [:], requiresAuthentication: Bool) {
         super.init(method: method, URLString: URLString, parameters: parameters, headers: headers, requiresAuthentication: requiresAuthentication)
     }

samples/client/petstore/swift5/urlsessionLibrary/Sources/PetstoreClient/URLSessionImplementations.swift

@@ -46,15 +46,6 @@ open class URLSessionRequestBuilder<T>: RequestBuilder<T> {
      */
     public var taskDidReceiveChallenge: PetstoreClientAPIChallengeHandler?
 
-    /**
-     May be assigned if you want to do any of those things:
-     - control the task completion
-     - intercept and handle errors like authorization
-     - retry the request.
-     */
-    @available(*, unavailable, message: "Please override execute() method to intercept and handle errors like authorization or retry the request. Check the Wiki for more info. https://github.com/OpenAPITools/openapi-generator/wiki/FAQ#how-do-i-implement-bearer-token-authentication-with-urlsession-on-the-swift-api-client")
-    public var taskCompletionShouldRetry: ((Data?, URLResponse?, Error?, @escaping (Bool) -> Void) -> Void)?
-
     required public init(method: String, URLString: String, parameters: [String: Any]?, headers: [String: String] = [:], requiresAuthentication: Bool) {
         super.init(method: method, URLString: URLString, parameters: parameters, headers: headers, requiresAuthentication: requiresAuthentication)
     }

samples/client/petstore/swift5/validation/PetstoreClient/Classes/OpenAPIs/URLSessionImplementations.swift

@@ -46,15 +46,6 @@ open class URLSessionRequestBuilder<T>: RequestBuilder<T> {
      */
     public var taskDidReceiveChallenge: PetstoreClientAPIChallengeHandler?
 
-    /**
-     May be assigned if you want to do any of those things:
-     - control the task completion
-     - intercept and handle errors like authorization
-     - retry the request.
-     */
-    @available(*, unavailable, message: "Please override execute() method to intercept and handle errors like authorization or retry the request. Check the Wiki for more info. https://github.com/OpenAPITools/openapi-generator/wiki/FAQ#how-do-i-implement-bearer-token-authentication-with-urlsession-on-the-swift-api-client")
-    public var taskCompletionShouldRetry: ((Data?, URLResponse?, Error?, @escaping (Bool) -> Void) -> Void)?
-
     required public init(method: String, URLString: String, parameters: [String: Any]?, headers: [String: String] = [:], requiresAuthentication: Bool) {
         super.init(method: method, URLString: URLString, parameters: parameters, headers: headers, requiresAuthentication: requiresAuthentication)
     }

samples/client/petstore/swift5/x-swift-hashable/PetstoreClient/Classes/OpenAPIs/URLSessionImplementations.swift

@@ -46,15 +46,6 @@ open class URLSessionRequestBuilder<T>: RequestBuilder<T> {
      */
     public var taskDidReceiveChallenge: PetstoreClientAPIChallengeHandler?
 
-    /**
-     May be assigned if you want to do any of those things:
-     - control the task completion
-     - intercept and handle errors like authorization
-     - retry the request.
-     */
-    @available(*, unavailable, message: "Please override execute() method to intercept and handle errors like authorization or retry the request. Check the Wiki for more info. https://github.com/OpenAPITools/openapi-generator/wiki/FAQ#how-do-i-implement-bearer-token-authentication-with-urlsession-on-the-swift-api-client")
-    public var taskCompletionShouldRetry: ((Data?, URLResponse?, Error?, @escaping (Bool) -> Void) -> Void)?
-
     required public init(method: String, URLString: String, parameters: [String: Any]?, headers: [String: String] = [:], requiresAuthentication: Bool) {
         super.init(method: method, URLString: URLString, parameters: parameters, headers: headers, requiresAuthentication: requiresAuthentication)
     }

samples/server/petstore/java-undertow/src/main/java/org/openapitools/handler/PathHandlerInterface.java

@@ -539,10 +539,10 @@ public interface PathHandlerInterface {
      * <p><b>Response headers</b>: [CodegenProperty{openApiType='integer', baseName='X-Rate-Limit', complexType='null', getter='getxRateLimit', setter='setxRateLimit', description='calls per hour allowed by the user', dataType='Integer', datatypeWithEnum='Integer', dataFormat='int32', name='xRateLimit', min='null', max='null', defaultValue='null', defaultValueWithParam=' = data.X-Rate-Limit;', baseType='Integer', containerType='null', containerTypeMapped='null', title='null', unescapedDescription='calls per hour allowed by the user', maxLength=null, minLength=null, pattern='null', example='null', jsonSchema='{
   "type" : "integer",
   "format" : "int32"
-}', minimum='null', maximum='null', exclusiveMinimum=false, exclusiveMaximum=false, required=false, deprecated=false, hasMoreNonReadOnly=false, isPrimitiveType=true, isModel=false, isContainer=false, isString=false, isNumeric=true, isInteger=true, isShort=true, isLong=false, isUnboundedInteger=false, isNumber=false, isFloat=false, isDouble=false, isDecimal=false, isByteArray=false, isBinary=false, isFile=false, isBoolean=false, isDate=false, isDateTime=false, isUuid=false, isUri=false, isEmail=false, isPassword=false, isFreeFormObject=false, isArray=false, isMap=false, isEnum=false, isInnerEnum=false, isEnumRef=false, isAnyType=false, isReadOnly=false, isWriteOnly=false, isNullable=false, isSelfReference=false, isCircularReference=false, isDiscriminator=false, isNew=false, isOverridden=null, _enum=null, allowableValues=null, items=null, additionalProperties=null, vars=[], requiredVars=[], mostInnerItems=null, vendorExtensions={}, hasValidation=false, isInherited=false, discriminatorValue='null', nameInCamelCase='XRateLimit', nameInSnakeCase='X_RATE_LIMIT', enumName='null', maxItems=null, minItems=null, maxProperties=null, minProperties=null, uniqueItems=false, uniqueItemsBoolean=null, multipleOf=null, isXmlAttribute=false, xmlPrefix='null', xmlName='null', xmlNamespace='null', isXmlWrapped=false, isNull=false, isVoid=false, getAdditionalPropertiesIsAnyType=false, getHasVars=false, getHasRequired=false, getHasDiscriminatorWithNonEmptyMapping=false, composedSchemas=null, hasMultipleTypes=false, requiredVarsMap=null, ref=null, schemaIsFromAdditionalProperties=false, isBooleanSchemaTrue=false, isBooleanSchemaFalse=false, format=int32, dependentRequired=null, contains=null}, CodegenProperty{openApiType='string', baseName='X-Expires-After', complexType='Date', getter='getxExpiresAfter', setter='setxExpiresAfter', description='date in UTC when token expires', dataType='Date', datatypeWithEnum='Date', dataFormat='date-time', name='xExpiresAfter', min='null', max='null', defaultValue='null', defaultValueWithParam=' = data.X-Expires-After;', baseType='Date', containerType='null', containerTypeMapped='null', title='null', unescapedDescription='date in UTC when token expires', maxLength=null, minLength=null, pattern='null', example='null', jsonSchema='{
+}', minimum='null', maximum='null', exclusiveMinimum=false, exclusiveMaximum=false, required=false, deprecated=false, hasMoreNonReadOnly=false, isPrimitiveType=true, isModel=false, isContainer=false, isString=false, isNumeric=true, isInteger=true, isShort=true, isLong=false, isUnboundedInteger=false, isNumber=false, isFloat=false, isDouble=false, isDecimal=false, isByteArray=false, isBinary=false, isFile=false, isBoolean=false, isDate=false, isDateTime=false, isUuid=false, isUri=false, isEmail=false, isPassword=false, isFreeFormObject=false, isArray=false, isMap=false, isEnum=false, isInnerEnum=false, isEnumRef=false, isAnyType=false, isReadOnly=false, isWriteOnly=false, isNullable=false, isSelfReference=false, isCircularReference=false, isDiscriminator=false, isNew=false, isOverridden=null, _enum=null, allowableValues=null, items=null, additionalProperties=null, vars=[], requiredVars=[], mostInnerItems=null, vendorExtensions={}, hasValidation=false, isInherited=false, discriminatorValue='null', nameInCamelCase='XRateLimit', nameInSnakeCase='X_RATE_LIMIT', enumName='null', maxItems=null, minItems=null, maxProperties=null, minProperties=null, uniqueItems=false, uniqueItemsBoolean=null, multipleOf=null, isXmlAttribute=false, xmlPrefix='null', xmlName='null', xmlNamespace='null', isXmlWrapped=false, isNull=false, isVoid=false, getAdditionalPropertiesIsAnyType=false, getHasVars=false, getHasRequired=false, getHasDiscriminatorWithNonEmptyMapping=false, composedSchemas=null, hasMultipleTypes=false, requiredVarsMap=null, ref=null, schemaIsFromAdditionalProperties=false, isBooleanSchemaTrue=false, isBooleanSchemaFalse=false, format=int32, dependentRequired=null, contains=null, constant=null}, CodegenProperty{openApiType='string', baseName='X-Expires-After', complexType='Date', getter='getxExpiresAfter', setter='setxExpiresAfter', description='date in UTC when token expires', dataType='Date', datatypeWithEnum='Date', dataFormat='date-time', name='xExpiresAfter', min='null', max='null', defaultValue='null', defaultValueWithParam=' = data.X-Expires-After;', baseType='Date', containerType='null', containerTypeMapped='null', title='null', unescapedDescription='date in UTC when token expires', maxLength=null, minLength=null, pattern='null', example='null', jsonSchema='{
   "type" : "string",
   "format" : "date-time"
-}', minimum='null', maximum='null', exclusiveMinimum=false, exclusiveMaximum=false, required=false, deprecated=false, hasMoreNonReadOnly=false, isPrimitiveType=false, isModel=false, isContainer=false, isString=false, isNumeric=false, isInteger=false, isShort=false, isLong=false, isUnboundedInteger=false, isNumber=false, isFloat=false, isDouble=false, isDecimal=false, isByteArray=false, isBinary=false, isFile=false, isBoolean=false, isDate=false, isDateTime=true, isUuid=false, isUri=false, isEmail=false, isPassword=false, isFreeFormObject=false, isArray=false, isMap=false, isEnum=false, isInnerEnum=false, isEnumRef=false, isAnyType=false, isReadOnly=false, isWriteOnly=false, isNullable=false, isSelfReference=false, isCircularReference=false, isDiscriminator=false, isNew=false, isOverridden=null, _enum=null, allowableValues=null, items=null, additionalProperties=null, vars=[], requiredVars=[], mostInnerItems=null, vendorExtensions={}, hasValidation=false, isInherited=false, discriminatorValue='null', nameInCamelCase='XExpiresAfter', nameInSnakeCase='X_EXPIRES_AFTER', enumName='null', maxItems=null, minItems=null, maxProperties=null, minProperties=null, uniqueItems=false, uniqueItemsBoolean=null, multipleOf=null, isXmlAttribute=false, xmlPrefix='null', xmlName='null', xmlNamespace='null', isXmlWrapped=false, isNull=false, isVoid=false, getAdditionalPropertiesIsAnyType=false, getHasVars=false, getHasRequired=false, getHasDiscriminatorWithNonEmptyMapping=false, composedSchemas=null, hasMultipleTypes=false, requiredVarsMap=null, ref=null, schemaIsFromAdditionalProperties=false, isBooleanSchemaTrue=false, isBooleanSchemaFalse=false, format=date-time, dependentRequired=null, contains=null}]</p>
+}', minimum='null', maximum='null', exclusiveMinimum=false, exclusiveMaximum=false, required=false, deprecated=false, hasMoreNonReadOnly=false, isPrimitiveType=false, isModel=false, isContainer=false, isString=false, isNumeric=false, isInteger=false, isShort=false, isLong=false, isUnboundedInteger=false, isNumber=false, isFloat=false, isDouble=false, isDecimal=false, isByteArray=false, isBinary=false, isFile=false, isBoolean=false, isDate=false, isDateTime=true, isUuid=false, isUri=false, isEmail=false, isPassword=false, isFreeFormObject=false, isArray=false, isMap=false, isEnum=false, isInnerEnum=false, isEnumRef=false, isAnyType=false, isReadOnly=false, isWriteOnly=false, isNullable=false, isSelfReference=false, isCircularReference=false, isDiscriminator=false, isNew=false, isOverridden=null, _enum=null, allowableValues=null, items=null, additionalProperties=null, vars=[], requiredVars=[], mostInnerItems=null, vendorExtensions={}, hasValidation=false, isInherited=false, discriminatorValue='null', nameInCamelCase='XExpiresAfter', nameInSnakeCase='X_EXPIRES_AFTER', enumName='null', maxItems=null, minItems=null, maxProperties=null, minProperties=null, uniqueItems=false, uniqueItemsBoolean=null, multipleOf=null, isXmlAttribute=false, xmlPrefix='null', xmlName='null', xmlNamespace='null', isXmlWrapped=false, isNull=false, isVoid=false, getAdditionalPropertiesIsAnyType=false, getHasVars=false, getHasRequired=false, getHasDiscriminatorWithNonEmptyMapping=false, composedSchemas=null, hasMultipleTypes=false, requiredVarsMap=null, ref=null, schemaIsFromAdditionalProperties=false, isBooleanSchemaTrue=false, isBooleanSchemaFalse=false, format=date-time, dependentRequired=null, contains=null, constant=null}]</p>
      *
      * <p><b>Produces</b>: [{isXml=true, mediaType=application/xml}, {isJson=true, mediaType=application/json}]</p>
      * <p><b>Returns</b>: {@link String}</p>

samples/server/petstore/python-flask/.openapi-generator/FILES

@@ -16,6 +16,7 @@ openapi_server/models/__init__.py
 openapi_server/models/api_response.py
 openapi_server/models/base_model.py
 openapi_server/models/category.py
+openapi_server/models/enum_model.py
 openapi_server/models/order.py
 openapi_server/models/pet.py
 openapi_server/models/tag.py

samples/server/petstore/python-flask/openapi_server/models/__init__.py

@@ -2,6 +2,7 @@
 # import models into model package
 from openapi_server.models.api_response import ApiResponse
 from openapi_server.models.category import Category
+from openapi_server.models.enum_model import EnumModel
 from openapi_server.models.order import Order
 from openapi_server.models.pet import Pet
 from openapi_server.models.tag import Tag

samples/server/petstore/python-flask/openapi_server/models/enum_model.py

@@ -0,0 +1,42 @@
+from datetime import date, datetime  # noqa: F401
+
+from typing import List, Dict  # noqa: F401
+
+from openapi_server.models.base_model import Model
+from openapi_server import util
+
+
+class EnumModel(Model):
+    """NOTE: This class is auto generated by OpenAPI Generator (https://openapi-generator.tech).
+
+    Do not edit the class manually.
+    """
+
+    """
+    allowed enum values
+    """
+    AVAILABLE_GREATER_THAN = 'available>'
+    PENDING_LESS_THAN = 'pending<'
+    SOLD = 'sold'
+    ENUM_1 = '1'
+    ENUM_2 = '2'
+    def __init__(self):  # noqa: E501
+        """EnumModel - a model defined in OpenAPI
+
+        """
+        self.openapi_types = {
+        }
+
+        self.attribute_map = {
+        }
+
+    @classmethod
+    def from_dict(cls, dikt) -> 'EnumModel':
+        """Returns the dict as a model
+
+        :param dikt: A dict.
+        :type: dict
+        :return: The EnumModel of this EnumModel.  # noqa: E501
+        :rtype: EnumModel
+        """
+        return util.deserialize_model(dikt, cls)

samples/server/petstore/python-flask/openapi_server/openapi/openapi.yaml

@@ -780,6 +780,14 @@ components:
           type: string
       title: An uploaded response
       type: object
+    EnumModel:
+      enum:
+      - available>
+      - pending<
+      - sold
+      - "1"
+      - "2"
+      type: string
     updatePetWithForm_request:
       properties:
         name: