Override description of alias schema

Author: gcatanese

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

@@ -1379,6 +1379,14 @@ public static Schema unaliasSchema(OpenAPI openAPI,
                 return schema;
             }
             Schema ref = allSchemas.get(simpleRef);
+
+            // override the description of the referenced component
+            if(ref != null) {
+                if(schema.getDescription() != null) {
+                    ref.setDescription(schema.getDescription());
+                }
+            }
+
             if (ref == null) {
                 if (!isRefToSchemaWithProperties(schema.get$ref())) {
                     once(LOGGER).warn("{} is not defined", schema.get$ref());

modules/openapi-generator/src/test/java/org/openapitools/codegen/utils/ModelUtilsTest.java

@@ -242,6 +242,24 @@ public void testAliasedTypeIsNotUnaliasedIfUsedForImportMapping() {
         Assert.assertEquals(stringSchema, ModelUtils.unaliasSchema(openAPI, emailSchema, new HashMap<>()));
     }
 
+    @Test
+    public void testOverrideAliasedSchemaDescription() {
+        Schema emailSchema = new Schema()
+                .$ref("#/components/schemas/Email")
+                .type("string")
+                .description("description of the reference");
+        StringSchema stringSchema = new StringSchema();
+        stringSchema.setDescription("description of Email component");
+
+        HashMap<String, String> schemaMappings = new HashMap<>();
+        schemaMappings.put("Email", "foo.bar.Email");
+
+        OpenAPI openAPI = TestUtils.createOpenAPIWithOneSchema("Email", stringSchema);
+
+        var unaliasSchema = ModelUtils.unaliasSchema(openAPI, emailSchema, schemaMappings);
+        Assert.assertEquals(unaliasSchema.getDescription(), "description of the reference");
+    }
+
     /**
      * Issue https://github.com/OpenAPITools/openapi-generator/issues/1624.
      * ModelUtils.isFreeFormObject() should not throw an NPE when passed an empty