Propagate deprecated property through $ref's (#6093)

* Propagate deprecated property through $ref's

As $ref is supposed to completely replace the definition of a property,
make sure we also include the 'deprecated' property when generating the
type of a $ref property.

This makes a property $ref'ing a deprecated schema also become deprecated.

* Clarify why we're messing around with $ref

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

@@ -2850,6 +2850,17 @@ public class DefaultCodegen implements CodegenConfig {
 
         if (p.getDeprecated() != null) {
             property.deprecated = p.getDeprecated();
+        } else if (p.get$ref() != null) {
+            // Since $ref should be replaced with the model it refers
+            // to, $ref'ing a model with 'deprecated' set should cause
+            // the property to reflect the model's 'deprecated' value.
+            String ref = ModelUtils.getSimpleRef(p.get$ref());
+            if (ref != null) {
+                Schema referencedSchema = ModelUtils.getSchemas(this.openAPI).get(ref);
+                if (referencedSchema != null && referencedSchema.getDeprecated() != null) {
+                    property.deprecated = referencedSchema.getDeprecated();
+                }
+            }
         }
         if (p.getReadOnly() != null) {
             property.isReadOnly = p.getReadOnly();

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

@@ -1409,6 +1409,19 @@ public class DefaultCodegenTest {
         Assert.assertFalse(codegen.fromProperty("customerCode",(Schema) requestProperties.get("customerCode")).deprecated);
     }
 
+    @Test
+    public void testDeprecatedRef() {
+        final OpenAPI openAPI = TestUtils.parseSpec("src/test/resources/3_0/model-deprecated.yaml");
+        new InlineModelResolver().flatten(openAPI);
+        final DefaultCodegen codegen = new DefaultCodegen();
+        codegen.setOpenAPI(openAPI);
+
+        final Map requestProperties = Collections.unmodifiableMap(openAPI.getComponents().getSchemas().get("complex").getProperties());
+
+        Assert.assertTrue(codegen.fromProperty("deprecated", (Schema)requestProperties.get("deprecated")).deprecated);
+        Assert.assertFalse(codegen.fromProperty("current", (Schema)requestProperties.get("current")).deprecated);
+    }
+
     @Test
     public void integerSchemaPropertyAndModelTest() {
         OpenAPI openAPI = TestUtils.createOpenAPI();

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

@@ -0,0 +1,36 @@
+openapi: 3.0.1
+info:
+  version: 1.0.0
+  title: Example
+  license:
+    name: MIT
+servers:
+  - url: http://api.example.xyz/v1
+
+components:
+  schemas:
+    deprecated:
+      type: object
+      deprecated: true
+      properties:
+        customerCode:
+          type: string
+          example: '0001'
+        firstName:
+          type: string
+          example: 'first'
+    current:
+      type: object
+      properties:
+        customerCode:
+          type: string
+          example: '0001'
+        firstName:
+          type: string
+          example: 'first'
+    complex:
+      properties:
+        deprecated:
+          $ref: "#/components/schemas/deprecated"
+        current:
+          type: boolean