Fix #1022 - Discriminator should only add Jackson JsonSubTypes when there's a parent class

client/deployment/src/main/resources/templates/libraries/microprofile/pojo.qute

@@ -7,7 +7,7 @@ import com.fasterxml.jackson.annotation.JsonProperty;
  **/
 {/if}
 {#include additionalModelTypeAnnotations.qute m=m/}
-{#if m.discriminator && m.discriminator.mappedModels && !m.discriminator.mappedModels.empty}
+{#if m.discriminator && m.discriminator.mappedModels && !m.discriminator.mappedModels.empty && m.children}
 @com.fasterxml.jackson.annotation.JsonIgnoreProperties(
   value = "{m.discriminator.propertyBaseName}", // ignore manually set {m.discriminator.propertyBaseName}, it will be automatically generated by Jackson during serialization
   allowSetters = true // allows the {m.discriminator.propertyBaseName} to be set during deserialization

client/deployment/src/test/java/io/quarkiverse/openapi/generator/deployment/wrapper/OpenApiClientGeneratorWrapperTest.java

@@ -84,8 +84,13 @@ void verifyOAuthDuplicateAnnotationOnCompositeAuthProvider() throws URISyntaxExc
         assertThat(oauthAnnotationsCount).isEqualTo(1);
     }
 
+    /**
+     * If the specification component has `oneOf` specified instead of `allOf`, the inner generator won't create a hierarchy of
+     * classes.
+     * In this situation, we can't generate the `JsonSubTypes` annotations.
+     */
     @Test
-    void verifyDiscriminatorGeneration() throws java.net.URISyntaxException, FileNotFoundException {
+    void verifyOneOfDiscriminatorGeneration() throws java.net.URISyntaxException, FileNotFoundException {
         OpenApiClientGeneratorWrapper generatorWrapper = createGeneratorWrapper("issue-852.json");
         final List<File> generatedFiles = generatorWrapper.generate("org.issue852");
 
@@ -96,6 +101,30 @@ void verifyDiscriminatorGeneration() throws java.net.URISyntaxException, FileNot
                 .filter(f -> f.getName().endsWith("PostRevisionForDocumentRequest.java")).findFirst();
         assertThat(classWithDiscriminator).isPresent();
 
+        final CompilationUnit compilationUnit = StaticJavaParser.parse(classWithDiscriminator.orElseThrow());
+        assertThat(compilationUnit.findFirst(ClassOrInterfaceDeclaration.class)
+                .flatMap(first -> first.getAnnotationByClass(com.fasterxml.jackson.annotation.JsonSubTypes.class)))
+                .isNotPresent();
+    }
+
+    /**
+     * Only generates `JsonSubTypes` annotations in case the class has children, otherwise skip since Jackson will complain in
+     * runtime.
+     * The file issue-1022.json is a classic example of a spec with allOf to denote how the Java POJO should be and how Jackson
+     * would serialize.
+     */
+    @Test
+    void verifyAllOfDiscriminatorGeneration() throws java.net.URISyntaxException, FileNotFoundException {
+        OpenApiClientGeneratorWrapper generatorWrapper = createGeneratorWrapper("issue-1022.json");
+        final List<File> generatedFiles = generatorWrapper.generate("org.issue1022");
+
+        assertNotNull(generatedFiles);
+        assertFalse(generatedFiles.isEmpty());
+
+        final Optional<File> classWithDiscriminator = generatedFiles.stream()
+                .filter(f -> f.getName().startsWith("Thing.java")).findFirst();
+        assertThat(classWithDiscriminator).isPresent();
+
         final CompilationUnit compilationUnit = StaticJavaParser.parse(classWithDiscriminator.orElseThrow());
         assertThat(compilationUnit.findFirst(ClassOrInterfaceDeclaration.class)
                 .flatMap(first -> first.getAnnotationByClass(com.fasterxml.jackson.annotation.JsonSubTypes.class)))

client/deployment/src/test/resources/openapi/issue-1022.json

@@ -0,0 +1,118 @@
+{
+  "openapi": "3.0.3",
+  "info": {
+    "title": "tuto API",
+    "version": "1.0.0-SNAPSHOT"
+  },
+  "servers": [
+    {
+      "url": "http://localhost:8080",
+      "description": "Auto generated value"
+    },
+    {
+      "url": "http://0.0.0.0:8080",
+      "description": "Auto generated value"
+    }
+  ],
+  "paths": {
+    "/": {
+      "get": {
+        "tags": [
+          "Default"
+        ],
+        "operationId": "get",
+        "responses": {
+          "200": {
+            "description": "OK",
+            "content": {
+              "application/json": {
+                "schema": {
+                  "$ref": "#/components/schemas/Data"
+                }
+              }
+            }
+          }
+        }
+      }
+    }
+  },
+  "components": {
+    "schemas": {
+      "Data": {
+        "required": [
+          "things"
+        ],
+        "type": "object",
+        "properties": {
+          "things": {
+            "type": "array",
+            "items": {
+              "$ref": "#/components/schemas/Thing"
+            },
+            "anyOf": [
+              {
+                "$ref": "#/components/schemas/SomeThing"
+              },
+              {
+                "$ref": "#/components/schemas/OtherThing"
+              }
+            ]
+          }
+        }
+      },
+      "OtherThing": {
+        "description": "Other thing",
+        "required": [
+          "other"
+        ],
+        "type": "object",
+        "allOf": [
+          {
+            "$ref": "#/components/schemas/Thing"
+          }
+        ],
+        "properties": {
+          "other": {
+            "type": "string"
+          }
+        }
+      },
+      "SomeThing": {
+        "description": "Some thing",
+        "required": [
+          "some"
+        ],
+        "type": "object",
+        "allOf": [
+          {
+            "$ref": "#/components/schemas/Thing"
+          }
+        ],
+        "properties": {
+          "some": {
+            "type": "string"
+          }
+        }
+      },
+      "Thing": {
+        "description": "Thing",
+        "required": [
+          "thing"
+        ],
+        "type": "object",
+        "properties": {
+          "thing": {
+            "type": "string"
+          }
+        },
+        "discriminator": {
+          "propertyName": "@type",
+          "mapping": {
+            "SomeThing": "#/components/schemas/SomeThing",
+            "OtherThing": "#/components/schemas/OtherThing"
+          }
+        }
+      }
+    }
+  }
+}

docs/modules/ROOT/pages/includes/quarkus-openapi-generator-server_quarkus.openapi.adoc

@@ -0,0 +1,13 @@
+[.configuration-legend]
+icon:lock[title=Fixed at build time] Configuration property fixed at build time - All other configuration properties are overridable at runtime
+[.configuration-reference.searchable, cols="80,.^10,.^10"]
+|===
+
+h|[.header-title]##Configuration property##
+h|Type
+h|Default
+
+3+|No configuration properties found.
+
+|===
+