fix(openapi): type "id" field according to ZModel schema type

packages/plugins/openapi/src/rest-generator.ts

@@ -906,16 +906,24 @@ export class RESTfulOpenAPIGenerator extends OpenAPIGeneratorBase {
             },
         };
 
+        let idFieldSchema: OAPI.SchemaObject = { type: 'string' };
+        if (idFields.length === 1) {
+            // FIXME: JSON:API actually requires id field to be a string,
+            // but currently the RESTAPIHandler returns the original data
+            // type as declared in the ZModel schema.
+            idFieldSchema = this.fieldTypeToOpenAPISchema(idFields[0].type);
+        }
+
         if (mode === 'create') {
             // 'id' is required if there's no default value
             const idFields = model.fields.filter((f) => isIdField(f));
             if (idFields.length === 1 && !hasAttribute(idFields[0], '@default')) {
-                properties = { id: { type: 'string' }, ...properties };
+                properties = { id: idFieldSchema, ...properties };
                 toplevelRequired.unshift('id');
             }
         } else {
             // 'id' always required for read and update
-            properties = { id: { type: 'string' }, ...properties };
+            properties = { id: idFieldSchema, ...properties };
             toplevelRequired.unshift('id');
         }
 

packages/plugins/openapi/tests/openapi-restful.test.ts

@@ -84,7 +84,7 @@ model Bar {
 
             const { name: output } = tmp.fileSync({ postfix: '.yaml' });
 
-            const options = buildOptions(model, modelFile, output, '3.1.0');
+            const options = buildOptions(model, modelFile, output, specVersion);
             await generate(model, options, dmmf);
 
             console.log(`OpenAPI specification generated for ${specVersion}: ${output}`);
@@ -324,7 +324,7 @@ model Foo {
 
             const { name: output } = tmp.fileSync({ postfix: '.yaml' });
 
-            const options = buildOptions(model, modelFile, output, '3.1.0');
+            const options = buildOptions(model, modelFile, output, specVersion);
             await generate(model, options, dmmf);
 
             console.log(`OpenAPI specification generated for ${specVersion}: ${output}`);
@@ -340,6 +340,28 @@ model Foo {
         }
     });
 
+    it('int field as id', async () => {
+        const { model, dmmf, modelFile } = await loadZModelAndDmmf(`
+plugin openapi {
+    provider = '${normalizePath(path.resolve(__dirname, '../dist'))}'
+}
+
+model Foo {
+    id Int @id @default(autoincrement())
+}
+        `);
+
+        const { name: output } = tmp.fileSync({ postfix: '.yaml' });
+
+        const options = buildOptions(model, modelFile, output, '3.0.0');
+        await generate(model, options, dmmf);
+        console.log(`OpenAPI specification generated: ${output}`);
+        await OpenAPIParser.validate(output);
+
+        const parsed = YAML.parse(fs.readFileSync(output, 'utf-8'));
+        expect(parsed.components.schemas.Foo.properties.id.type).toBe('integer');
+    });
+
     it('exposes individual fields from a compound id as attributes', async () => {
         const { model, dmmf, modelFile } = await loadZModelAndDmmf(`
 plugin openapi {