fix: suppress $batch path for REST services

CHANGELOG.md

@@ -20,6 +20,7 @@ The format is based on [Keep a Changelog](http://keepachangelog.com/).
 - Back-reference navigation properties on child entities in compositions (the generated `parent` nav pointing back up) are no longer emitted in the OpenAPI read schema
 - Implicitly auto-exposed composition targets (annotated `@cds.autoexposed` by the CDS compiler) no longer generate top-level GET paths that CAP would reject with 405
 - OpenAPI compilation is now pure: the input CSN is no longer mutated during compilation
+- Services annotated with `@protocol: 'rest'` no longer include a `/$batch` path in the generated OpenAPI document
 ### Security
 
 ## [1.6.0] - 2026-08-04

lib/compile/csdl2openapi.js

@@ -9,6 +9,8 @@ const propertyUtil = require('./property-util');
 const pluralize = require('pluralize')
 const DEBUG = cds.debug('openapi');  // Initialize cds.debug with the 'openapi'
 
+const isODataProtocol = (protocol) => !protocol || protocol.startsWith('odata');
+
 //TODO
 // - Core.Example for complex types
 // - reduce number of loops over schemas
@@ -122,7 +124,7 @@ function normalizeDiagramFlag(diagram) {
 /**
  * Construct an OpenAPI description from a CSDL document
  * @param {CSDL} csdl CSDL document
- * @param {{ url?: string, servers?: object, odataVersion?: string, scheme?: string, host?: string, basePath?: string, diagram?: boolean, maxLevels?: number, shortActionPaths?: boolean }} options Optional parameters
+ * @param {{ url?: string, servers?: object, odataVersion?: string, protocol?: string, scheme?: string, host?: string, basePath?: string, diagram?: boolean, maxLevels?: number, shortActionPaths?: boolean }} options Optional parameters
  * @return {*} OpenAPI description
  */
 module.exports.csdl2openapi = function (
@@ -131,6 +133,7 @@ module.exports.csdl2openapi = function (
         url: serviceRoot,
         servers: serversObject,
         odataVersion,
+        protocol,
         scheme = 'https',
         host = 'localhost',
         basePath = '/service-root',
@@ -511,7 +514,7 @@ module.exports.csdl2openapi = function (
                 DEBUG?.(`Unrecognized entity container child: ${name}`);
             }
         })
-        if (resources.length > 0) pathItemBatch(paths, container);
+        if (resources.length > 0 && isODataProtocol(protocol)) pathItemBatch(paths, container);
         return Object.keys(paths).sort().reduce((p, c) => (p[c] = paths[c], p), {});
     }
 

lib/compile/index.js

@@ -94,6 +94,7 @@ function _getOpenApi(csdl, options, serviceName = "") {
     }
 
     sOptions.url = url;
+    sOptions.protocol = protocol;
 
     const openapi = csdl2openapi.csdl2openapi(csdl, sOptions);
 

test/lib/compile/openapi.test.js

@@ -305,6 +305,19 @@ service CatalogService {
       '@protocol must not be mutated by toOpenApi');
   });
 
+  test('REST service does not include /$batch path', () => {
+    const csn = cds.compile.to.csn(`
+      @path: '/rest/v1/myRestAPI'
+      @protocol: 'rest'
+      service MyRestAPI {
+        entity Items { key ID : UUID; }
+      }`
+    );
+    const openapi = toOpenApi(csn);
+    assert.strictEqual(openapi.paths?.['/$batch'], undefined,
+      '/$batch must not be present in OpenAPI output for a REST service');
+  });
+
   test('options: Multiple servers', () => {
     const csn = cds.compile.to.csn(`
       service A {entity E { key ID : UUID; };};`