Fix generating model with discriminator.

Fixed #1163

Author: altro3

openapi-generator/src/main/java/io/micronaut/openapi/generator/AbstractMicronautJavaCodegen.java

@@ -794,6 +794,10 @@ public Map<String, ModelsMap> postProcessAllModels(Map<String, ModelsMap> objs)
             List<CodegenProperty> requiredVars = model.vars.stream().filter(v -> v.required).collect(Collectors.toList());
             model.vendorExtensions.put("requiredVars", requiredVars);
             model.vendorExtensions.put("areRequiredVarsAndReadOnlyVars", !requiredVars.isEmpty() && !model.readOnlyVars.isEmpty());
+            if (model.discriminator != null) {
+                model.vendorExtensions.put("hasMappedModels", !model.discriminator.getMappedModels().isEmpty());
+                model.vendorExtensions.put("hasMultipleMappedModels", model.discriminator.getMappedModels().size() > 1);
+            }
         }
 
         return objs;

openapi-generator/src/main/resources/templates/java-micronaut/common/model/typeInfoAnnotation.mustache

@@ -3,12 +3,17 @@
   value = "{{{discriminator.propertyBaseName}}}", // ignore manually set {{{discriminator.propertyBaseName}}}, it will be automatically generated by Jackson during serialization
   allowSetters = true // allows the {{{discriminator.propertyBaseName}}} to be set during deserialization
 )
-@JsonTypeInfo(use = JsonTypeInfo.Id.NAME, include = JsonTypeInfo.As.PROPERTY, property = "{{{discriminator.propertyBaseName}}}"{{^micronaut_serde_jackson}}, visible = true{{/micronaut_serde_jackson}})
+@JsonTypeInfo(use = JsonTypeInfo.Id.NAME, property = "{{{discriminator.propertyBaseName}}}"{{^micronaut_serde_jackson}}, visible = true{{/micronaut_serde_jackson}})
 {{#discriminator}}
-    {{#mappedModels.0}}
-@JsonSubTypes({ {{#mappedModels}}
+    {{#vendorExtensions.hasMappedModels}}
+        {{#vendorExtensions.hasMultipleMappedModels}}
+@JsonSubTypes({{openbrace}}{{#mappedModels}}
     @JsonSubTypes.Type(value = {{modelName}}.class, name = "{{^vendorExtensions.x-discriminator-value}}{{mappingName}}{{/vendorExtensions.x-discriminator-value}}{{#vendorExtensions.x-discriminator-value}}{{{vendorExtensions.x-discriminator-value}}}{{/vendorExtensions.x-discriminator-value}}"){{^-last}},{{/-last}}
-{{/mappedModels}}{{closebarace}})
-    {{/mappedModels.0}}
+{{/mappedModels}}{{closebrace}})
+        {{/vendorExtensions.hasMultipleMappedModels}}
+        {{^vendorExtensions.hasMultipleMappedModels}}
+@JsonSubTypes({{#mappedModels}}@JsonSubTypes.Type(value = {{modelName}}.class, name = "{{^vendorExtensions.x-discriminator-value}}{{mappingName}}{{/vendorExtensions.x-discriminator-value}}{{#vendorExtensions.x-discriminator-value}}{{{vendorExtensions.x-discriminator-value}}}{{/vendorExtensions.x-discriminator-value}}"){{/mappedModels}})
+        {{/vendorExtensions.hasMultipleMappedModels}}
+    {{/vendorExtensions.hasMappedModels}}
 {{/discriminator}}
 {{/jackson}}