Adds updates from Sebastien Rosset

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

@@ -7,7 +7,18 @@
 import java.util.Objects;
 import java.util.Set;
 
+/**
+ * This class encapsulates the OpenAPI discriminator construct, as specified at
+ * https://github.com/OAI/OpenAPI-Specification/blob/master/versions/3.0.3.md#discriminatorObject.
+ *
+ * When request bodies or response payloads may be one of a number of different schemas,
+ * a discriminator object can be used to aid in serialization, deserialization, and validation.
+ * The discriminator is a specific object in a schema which is used to inform the consumer of
+ * the specification of an alternative schema based on the value associated with it.
+ */
 public class CodegenDiscriminator {
+    // The name of the property in the payload that will hold the discriminator value.
+    // This is the propertyName as specified in the OpenAPI discriminator object.
     private String propertyName;
     private String propertyBaseName;
     private String propertyGetter;
@@ -63,8 +74,21 @@ public void setMappedModels(Set<MappedModel> mappedModels) {
         this.mappedModels = mappedModels;
     }
 
+    /**
+     * An object to hold discriminator mappings between payload values and schema names or
+     * references.
+     *
+     * In the OpenAPI document, the discriminator "mapping" attribute is optional.
+     * In scenarios where the value of the discriminator field does not match the schema name
+     * or implicit mapping is not possible, an optional mapping definition MAY be used.
+     * In OpenAPITools codegen, the MappedModel is the union of all the discriminator mappings,
+     * both explicitly defined in the OpenAPI document and inherited from oneOf/allOf/anyOf.
+     */
     public static class MappedModel implements Comparable<MappedModel>{
+        // The value of the discriminator property in the payload.
         private String mappingName;
+        // The OAS schema name. It is obtained from the OAS document, and the string value
+        // is converted to a sanitized, internal representation within codegen.
         private String modelName;
 
         public MappedModel(String mappingName, String modelName) {
@@ -135,4 +159,4 @@ public String toString() {
         sb.append('}');
         return sb.toString();
     }
-}
+}

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

@@ -2586,7 +2586,7 @@ protected List<MappedModel> getOneOfAnyOfDescendants(String composedSchemaName,
                 descendentSchemas.add(mm);
                 Schema cs = ModelUtils.getSchema(openAPI, modelName);
                 Map<String, Object> vendorExtensions = cs.getExtensions();
-                if (vendorExtensions != null && !vendorExtensions.isEmpty()) {
+                if (vendorExtensions != null && !vendorExtensions.isEmpty() && vendorExtensions.containsKey("x-discriminator-value")) {
                     String xDiscriminatorValue = (String) vendorExtensions.get("x-discriminator-value");
                     mm = new MappedModel(xDiscriminatorValue, toModelName(modelName));
                     descendentSchemas.add(mm);
@@ -2641,7 +2641,7 @@ protected List<MappedModel> getAllOfDescendants(String thisSchemaName, OpenAPI o
             descendentSchemas.add(mm);
             Schema cs = schemas.get(currentSchemaName);
             Map<String, Object> vendorExtensions = cs.getExtensions();
-            if (vendorExtensions != null && !vendorExtensions.isEmpty()) {
+            if (vendorExtensions != null && !vendorExtensions.isEmpty() && vendorExtensions.containsKey("x-discriminator-value")) {
                 String xDiscriminatorValue = (String) vendorExtensions.get("x-discriminator-value");
                 mm = new MappedModel(xDiscriminatorValue, toModelName(currentSchemaName));
                 descendentSchemas.add(mm);