[Java/Core] Adds properties to ComposedSchema models when they exist (#4482)

* Adds comment in java test where we need to check the fruit model

* Adds oneOf test to DefaultCodegenTest.java, adds code to include properties in composed schema

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

@@ -1788,6 +1788,17 @@ public class DefaultCodegen implements CodegenConfig {
             Map<String, Schema> allProperties = new LinkedHashMap<String, Schema>();
             List<String> allRequired = new ArrayList<String>();
 
+            // if schema has properties outside of allOf/oneOf/anyOf also add them to m
+            if (schema.getProperties() != null) {
+                addVars(m, unaliasPropertySchema(schema.getProperties()), schema.getRequired(), null, null);
+            }
+
+            // uncomment this when https://github.com/swagger-api/swagger-parser/issues/1252 is resolved
+            // if schema has additionalproperties outside of allOf/oneOf/anyOf also add it to m
+            // if (schema.getAdditionalProperties() != null) {
+            //     addAdditionPropertiesToCodeGenModel(m, schema);
+            // }
+
             // parent model
             final String parentName = ModelUtils.getParentName(composed, allDefinitions);
             final List<String> allParents = ModelUtils.getAllParentsName(composed, allDefinitions);

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

@@ -268,6 +268,41 @@ public class DefaultCodegenTest {
         Assert.assertEquals(type, "oneOf<ObjA,ObjB>");
     }
 
+    @Test
+    public void testComposedSchemaOneOfWithProperties() {
+        final OpenAPI openAPI = TestUtils.parseSpec("src/test/resources/3_0/oneOf.yaml");
+        final DefaultCodegen codegen = new DefaultCodegen();
+
+        final Schema schema = openAPI.getComponents().getSchemas().get("fruit");
+        codegen.setOpenAPI(openAPI);
+        CodegenModel fruit = codegen.fromModel("Fruit", schema);
+
+        Set<String> oneOf = new TreeSet<String>();
+        oneOf.add("Apple");
+        oneOf.add("Banana");
+        Assert.assertEquals(fruit.oneOf, oneOf);
+        Assert.assertEquals(fruit.optionalVars.size(), 3);
+        Assert.assertEquals(fruit.vars.size(), 3);
+        // make sure that fruit has the property color
+        boolean colorSeen = false;
+        for (CodegenProperty cp : fruit.vars) {
+            if (cp.name.equals("color")) {
+                colorSeen = true;
+                break;
+            }
+        }
+        Assert.assertTrue(colorSeen);
+        colorSeen = false;
+        for (CodegenProperty cp : fruit.optionalVars) {
+            if (cp.name.equals("color")) {
+                colorSeen = true;
+                break;
+            }
+        }
+        Assert.assertTrue(colorSeen);
+    }
+
+
     @Test
     public void testEscapeText() {
         final DefaultCodegen codegen = new DefaultCodegen();

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

@@ -22,6 +22,9 @@ components:
          oneOf:
             - $ref: '#/components/schemas/apple'
             - $ref: '#/components/schemas/banana'
+         # additionalProperties:
+         #    type: string
+         # uncomment this when https://github.com/swagger-api/swagger-parser/issues/1252 is resolved
       apple:
          title: apple
          type: object