Get Parameter's PathItems from first child if doesn't exist

src/Kiota.Builder/KiotaBuilder.cs

@@ -1081,9 +1081,10 @@
         var parameterName = string.Join(OpenAPIUrlTreeNodePathSeparator, currentNode.Path.Split(OpenAPIUrlTreeNodePathSeparator, StringSplitOptions.RemoveEmptyEntries)
                                         .Skip(parentNode.Path.Count(static x => x == OpenAPIUrlTreeNodePathSeparator)))
                                         .Trim(OpenAPIUrlTreeNodePathSeparator, ForwardSlash, '{', '}');
-        var parameter = currentNode.PathItems.TryGetValue(Constants.DefaultOpenApiLabel, out var pathItem) ? pathItem.Parameters
+        var pathItems = GetPathItems(currentNode);
+        var parameter = pathItems.TryGetValue(Constants.DefaultOpenApiLabel, out var pathItem) ? pathItem.Parameters
                         .Select(static x => new { Parameter = x, IsPathParameter = true })
-                        .Union(currentNode.PathItems[Constants.DefaultOpenApiLabel].Operations.SelectMany(static x => x.Value.Parameters).Select(static x => new { Parameter = x, IsPathParameter = false }))
+                        .Union(pathItems[Constants.DefaultOpenApiLabel].Operations.SelectMany(static x => x.Value.Parameters).Select(static x => new { Parameter = x, IsPathParameter = false }))
                         .OrderBy(static x => x.IsPathParameter)
                         .Select(static x => x.Parameter)
                         .FirstOrDefault(x => x.Name.Equals(parameterName, StringComparison.OrdinalIgnoreCase) && x.In == ParameterLocation.Path) :
@@ -1106,6 +1107,23 @@
         };
         return result;
     }
+    private static IDictionary<string, OpenApiPathItem> GetPathItems(OpenApiUrlTreeNode currentNode. bool validateIsParamterNode = true)
+    {
+        if((!validateIsParameterNode || currentNode.IsParameter) && currentNode.PathItems.Any())
+        {
+            return currentNode.PathItems;
+        }
+
+        if (currentNode.Children.Any())
+        {
+            return currentNode.Children
+                .SelectMany(static x => GetPathItems(x, false))
+                .DistinctBy(static x => x.Key, StringComparer.Ordinal)
+                .ToDictionary(static x => x.Key, static x => x.Value, StringComparer.Ordinal);
+        }
+
+        return new Dictionary<string, OpenApiPathItem>();
+    }
     private CodeIndexer[] CreateIndexer(string childIdentifier, string childType, CodeParameter parameter, OpenApiUrlTreeNode currentNode, OpenApiUrlTreeNode parentNode)
     {
         logger.LogTrace("Creating indexer {Name}", childIdentifier);

tests/Kiota.Builder.Tests/KiotaBuilderTests.cs

@@ -6204,6 +6204,23 @@ public async Task IndexerTypeIsAccurateAndBackwardCompatibleIndexersAreAdded()
             application/json:
               schema:
                 $ref: '#/components/schemas/microsoft.graph.post'
+  /authors/{author-id}/posts:
+    get:
+      parameters:
+        - name: author-id
+          in: path
+          required: true
+          description: The id of the author's posts to retrieve
+          schema:
+            type: string
+            format: uuid
+      responses:
+        200:
+          description: Success!
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/microsoft.graph.post'
 components:
   schemas:
     microsoft.graph.post:
@@ -6218,24 +6235,44 @@ public async Task IndexerTypeIsAccurateAndBackwardCompatibleIndexersAreAdded()
         var document = await builder.CreateOpenApiDocumentAsync(fs);
         var node = builder.CreateUriSpace(document!);
         var codeModel = builder.CreateSourceModel(node);
-        var collectionRequestBuilderNamespace = codeModel.FindNamespaceByName("ApiSdk.me.posts");
-        Assert.NotNull(collectionRequestBuilderNamespace);
-        var collectionRequestBuilder = collectionRequestBuilderNamespace.FindChildByName<CodeClass>("postsRequestBuilder");
-        var collectionIndexer = collectionRequestBuilder.Indexer;
-        Assert.NotNull(collectionIndexer);
-        Assert.Equal("integer", collectionIndexer.IndexParameter.Type.Name);
-        Assert.Equal("The id of the pet to retrieve", collectionIndexer.IndexParameter.Documentation.Description, StringComparer.OrdinalIgnoreCase);
-        Assert.False(collectionIndexer.IndexParameter.Type.IsNullable);
-        Assert.False(collectionIndexer.Deprecation.IsDeprecated);
-        var collectionStringIndexer = collectionRequestBuilder.FindChildByName<CodeIndexer>($"{collectionIndexer.Name}-string");
-        Assert.NotNull(collectionStringIndexer);
-        Assert.Equal("string", collectionStringIndexer.IndexParameter.Type.Name);
-        Assert.True(collectionStringIndexer.IndexParameter.Type.IsNullable);
-        Assert.True(collectionStringIndexer.Deprecation.IsDeprecated);
-        var itemRequestBuilderNamespace = codeModel.FindNamespaceByName("ApiSdk.me.posts.item");
-        Assert.NotNull(itemRequestBuilderNamespace);
-        var itemRequestBuilder = itemRequestBuilderNamespace.FindChildByName<CodeClass>("postItemRequestBuilder");
-        Assert.Equal(collectionIndexer.ReturnType.Name, itemRequestBuilder.Name);
+
+        var postsCollectionRequestBuilderNamespace = codeModel.FindNamespaceByName("ApiSdk.me.posts");
+        Assert.NotNull(postsCollectionRequestBuilderNamespace);
+        var postsCollectionRequestBuilder = postsCollectionRequestBuilderNamespace.FindChildByName<CodeClass>("postsRequestBuilder");
+        var postsCollectionIndexer = postsCollectionRequestBuilder.Indexer;
+        Assert.NotNull(postsCollectionIndexer);
+        Assert.Equal("integer", postsCollectionIndexer.IndexParameter.Type.Name);
+        Assert.Equal("The id of the pet to retrieve", postsCollectionIndexer.IndexParameter.Documentation.Description, StringComparer.OrdinalIgnoreCase);
+        Assert.False(postsCollectionIndexer.IndexParameter.Type.IsNullable);
+        Assert.False(postsCollectionIndexer.Deprecation.IsDeprecated);
+        var postsCollectionStringIndexer = postsCollectionRequestBuilder.FindChildByName<CodeIndexer>($"{postsCollectionIndexer.Name}-string");
+        Assert.NotNull(postsCollectionStringIndexer);
+        Assert.Equal("string", postsCollectionStringIndexer.IndexParameter.Type.Name);
+        Assert.True(postsCollectionStringIndexer.IndexParameter.Type.IsNullable);
+        Assert.True(postsCollectionStringIndexer.Deprecation.IsDeprecated);
+        var postsItemRequestBuilderNamespace = codeModel.FindNamespaceByName("ApiSdk.me.posts.item");
+        Assert.NotNull(postsItemRequestBuilderNamespace);
+        var postsItemRequestBuilder = postsItemRequestBuilderNamespace.FindChildByName<CodeClass>("postItemRequestBuilder");
+        Assert.Equal(postsCollectionIndexer.ReturnType.Name, postsItemRequestBuilder.Name);
+
+        var authorsCollectionRequestBuilderNamespace = codeModel.FindNamespaceByName("ApiSdk.authors");
+        Assert.NotNull(authorsCollectionRequestBuilderNamespace);
+        var authorsCollectionRequestBuilder = authorsCollectionRequestBuilderNamespace.FindChildByName<CodeClass>("authorsRequestBuilder");
+        var authorsCollectionIndexer = authorsCollectionRequestBuilder.Indexer;
+        Assert.NotNull(authorsCollectionIndexer);
+        Assert.Equal("Guid", authorsCollectionIndexer.IndexParameter.Type.Name);
+        Assert.Equal("The id of the author's posts to retrieve", authorsCollectionIndexer.IndexParameter.Documentation.Description, StringComparer.OrdinalIgnoreCase);
+        Assert.False(authorsCollectionIndexer.IndexParameter.Type.IsNullable);
+        Assert.False(authorsCollectionIndexer.Deprecation.IsDeprecated);
+        var authorsCllectionStringIndexer = authorsCollectionRequestBuilder.FindChildByName<CodeIndexer>($"{authorsCollectionIndexer.Name}-string");
+        Assert.NotNull(authorsCllectionStringIndexer);
+        Assert.Equal("string", authorsCllectionStringIndexer.IndexParameter.Type.Name);
+        Assert.True(authorsCllectionStringIndexer.IndexParameter.Type.IsNullable);
+        Assert.True(authorsCllectionStringIndexer.Deprecation.IsDeprecated);
+        var authorsItemRequestBuilderNamespace = codeModel.FindNamespaceByName("ApiSdk.authors.item");
+        Assert.NotNull(authorsItemRequestBuilderNamespace);
+        var authorsItemRequestBuilder = authorsItemRequestBuilderNamespace.FindChildByName<CodeClass>("authorItemRequestBuilder");
+        Assert.Equal(authorsCollectionIndexer.ReturnType.Name, authorsItemRequestBuilder.Name);
     }
     [Fact]
     public async Task MapsBooleanEnumToBooleanType()