fix: suppress $batch path for REST services

CHANGELOG.md

@@ -19,6 +19,7 @@ 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 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
@@ -88,15 +90,16 @@
 /**
  * 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 (
     csdl,
     {
         url: serviceRoot,
         servers: serversObject,
         odataVersion,
+        protocol,
         scheme = 'https',
         host = 'localhost',
         basePath = '/service-root',
@@ -460,7 +463,7 @@
                 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), {});
     }
 
@@ -478,7 +481,7 @@
      * @param {number} options.level Number of navigation segments so far
      * @param {string} options.navigationPath Path for finding navigation restrictions
      */
     function pathItems({ paths, prefix, prefixParameters, element, root, sourceName, targetName, target, level, navigationPath }) {
         const name = prefix.substring(prefix.lastIndexOf('/') + 1);
         const type = meta.modelElement(element.$Type);
         const pathItem = {};
@@ -756,7 +759,7 @@
      * @param {boolean} options.byKey Read by key
      * @param {array} options.nonExpandable Non-expandable navigation properties
      */
     function operationRead({ pathItem, element, name, sourceName, targetName, target, level, restrictions, byKey, nonExpandable }) {
         const targetRestrictions = target?.[meta.voc.Capabilities.ReadRestrictions];
         const readRestrictions = restrictions.ReadRestrictions || targetRestrictions || {};
         const readByKeyRestrictions = readRestrictions.ReadByKeyRestrictions;
@@ -1226,7 +1229,7 @@
      * @param {*} options.restrictions Navigation property restrictions of navigation segment
      * @param {boolean} [options.byKey=false] Update by key
      */
     function operationUpdate({ pathItem, element, name, sourceName, target, level, restrictions, byKey = false }) {
         const updateRestrictions = restrictions.UpdateRestrictions || target?.[meta.voc.Capabilities.UpdateRestrictions] || {};
         const countRestrictions = target?.[meta.voc.Capabilities.CountRestrictions]?.Countable === false;
         if (updateRestrictions.Updatable !== false && !element[meta.voc.Core.Immutable]) {
@@ -1317,7 +1320,7 @@
      */
     function pathItemsForMediaStream({ paths, prefix, prefixParameters, type, name, sourceName }) {
         if (type.$HasStream) {
             const mediaTypes = type[meta.voc.Core.AcceptableMediaTypes]?.map(t => t['$EnumMember'] ?? t) ?? [];
             const contentTypes = mediaTypes.length > 0 ? mediaTypes : ['*/*'];
             const mediaContent = Object.fromEntries(contentTypes.map(ct => [ct, { schema: { type: 'string', format: 'binary' } }]));
             const lname = splitName(name);
@@ -1647,7 +1650,7 @@
      * @param {string} options.sourceName Name of path source
      * @param {*} [options.actionImport={}] Action import
      */
     function pathItemAction({ paths, prefix, prefixParameters, actionName, overload, sourceName, actionImport = {} }) {
         const name = actionName.indexOf('.') === -1 ? actionName : nameParts(actionName).name;
         const pathItem = {
             post: {
@@ -1737,7 +1740,7 @@
      * @param {string} options.sourceName Name of path source
      * @param {*} [options.functionImport={}] Function Import
      */
     function pathItemFunction({ paths, prefix, prefixParameters, functionName, overload, sourceName, functionImport = {} }) {
         const name = functionName.indexOf('.') === -1 ? functionName : nameParts(functionName).name;
         let parameters = overload.$Parameter || [];
         if (overload.$IsBound) parameters = parameters.slice(1);
@@ -1746,7 +1749,7 @@
 
         const implicitAliases = csdl.$Version > '4.0' || parameters.some(p => p[meta.voc.Core.OptionalParameter]);
 
         parameters.forEach(p => {
             const description = getDescriptionWithFallback(p);
             /** @type {Parameter} */
             const param = {
@@ -2126,7 +2129,7 @@
      * @param {string} options.suffix Suffix for read/create/update
      * @return {*} Map of Schemas Objects
      */
     function schemasForStructuredType({ schemas, qualifier, name, type, suffix }) {
         const schemaName = `${qualifier}.${name}${suffix}`;
         const baseName = `${qualifier}.${name}`;
         const isKey = keyMap(type);
@@ -2142,7 +2145,7 @@
         const properties = propertiesOfStructuredType(type);
         const expandRestrictions = type[meta.voc.Capabilities.ExpandRestrictions] ?? {};
         const nonExpandableProperties = expandRestrictions.NonExpandableProperties ?? [];
         Object.keys(properties).forEach(iName => {
             if (nonExpandableProperties.includes(iName)) return;
 
             const property = properties[iName];

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; };};`