Parameter aliases conflict with system query options (#66)

* oasis-tcs/odata-openapi#324

* Test case

* Don't change indentation style

---------

Co-authored-by: Dipto <[email protected]>

Author: HeikoTheissen

lib/compile/csdl2openapi.js

@@ -32,6 +32,23 @@ const TITLE_SUFFIX = {
     "-update": " (for update)",
 };
 
+const SYSTEM_QUERY_OPTIONS = [
+    "compute",
+    "expand",
+    "select",
+    "filter",
+    "search",
+    "count",
+    "orderby",
+    "skip",
+    "top",
+    "format",
+    "index",
+    "schemaversion",
+    "skiptoken",
+    "apply",
+];
+
 /**
  * ODM annotations in CDS that should be converted into OpenAPI.
  */
@@ -1646,7 +1663,13 @@ see [Expand](http://docs.oasis-open.org/odata/odata/v4.01/odata-v4.01-part1-prot
                 || type && ['ComplexType', 'EntityType'].includes(type.$Kind)
                 || type && type.$UnderlyingType == 'Edm.Stream') {
                 param.in = 'query';
-                if (implicitAliases) {
+                if (
+                    implicitAliases &&
+                    csdl.$Version !== '2.0' &&
+                    SYSTEM_QUERY_OPTIONS.includes(p.$Name.toLowerCase())
+                ) {
+                    param.name = '@' + p.$Name;
+                } else if (implicitAliases) {
                     param.name = p.$Name;
                 } else {
                     pathSegments.push(p.$Name + '=@' + p.$Name);
@@ -1669,7 +1692,14 @@ see [Expand](http://docs.oasis-open.org/odata/odata/v4.01/odata-v4.01-part1-prot
                     pathSegments.push(p.$Name + "={" + p.$Name + "}");
                     param.in = 'path';
                 }
-                param.name = p.$Name;
+                if (
+                    implicitAliases &&
+                    csdl.$Version !== '2.0' &&
+                    SYSTEM_QUERY_OPTIONS.includes(p.$Name.toLowerCase())
+                )
+                    param.name = '@' + p.$Name;
+                else
+                    param.name = p.$Name;
                 if (!p.$Type || p.$Type === "Edm.String" || (type && (!type.$Type || type.$Type === "Edm.String"))) {
                     if (description) param.description += "  \n";
                     else param.description = "";

test/lib/compile/csdl2openapi.test.js

@@ -814,6 +814,75 @@ describe('Edge cases', function () {
         assert.deepStrictEqual(actual.paths[path].get.tags, expected.paths[path].get.tags, 'function tags');
     })
 
+    it('function with @ parameter aliases', function () {
+      const csdl = {
+        $Version: '4.01',
+        $Reference: {
+          dummy: {
+            $Include: [{ $Namespace: 'Org.OData.Core.V1', $Alias: 'Core' }],
+          },
+        },
+        $EntityContainer: 'model.Container',
+        model: {
+          $Alias: 'this',
+          FavoritePhotos: [
+            {
+              $Kind: 'Function',
+              $Parameter: [
+                {
+                  $Name: 'SKIP',
+                  $Type: 'Edm.Date',
+                  $Collection: true,
+                  '@Core.Description': 'Dates to be skipped',
+                },
+                {
+                  $Name: 'filter',
+                  '@Core.Description': 'Boolean expression to filter the result',
+                },
+              ],
+              $ReturnType: {},
+            },
+          ],
+          Container: {
+            fav: { $Function: 'this.FavoritePhotos' },
+          },
+        },
+      };
+      const expected = {
+        paths: {
+          '/fav': {
+            get: {
+              parameters: [
+                {
+                  name: '@SKIP',
+                  in: 'query',
+                  required: true,
+                  description:
+                    'Dates to be skipped  \nThis is a URL-encoded JSON array with items of type Edm.Date, see [Complex and Collection Literals](https://docs.oasis-open.org/odata/odata/v4.01/odata-v4.01-part2-url-conventions.html#sec_ComplexandCollectionLiterals)',
+                  schema: { type: 'string' },
+                  example: '[]',
+                },
+                {
+                  name: '@filter',
+                  in: 'query',
+                  required: true,
+                  schema: { type: 'string', pattern: "^'([^']|'')*'$" },
+                  description:
+                    'Boolean expression to filter the result  \nString value needs to be enclosed in single quotes',
+                },
+              ],
+              summary: 'Invokes function FavoritePhotos',
+              tags: ['Service Operations'],
+            },
+          },
+        },
+      };
+      const actual = lib.csdl2openapi(csdl, { diagram: true });
+      delete actual.paths['/$batch'];
+      delete actual.paths['/fav'].get.responses;
+      assert.deepStrictEqual(actual.paths, expected.paths);
+    });
+    
     it('return type with facets', function () {
         const csdl = {
             $EntityContainer: 'this.Container',