[TypeScript] Error "Function deserializeIntoWithPath not found" for GITHUB.COM api

[WolfgangHG]

Found as part of #7774

Using the source code from 2026-06-15 and this command:

.\it\generate-code.ps1 -descriptionUrl https://raw.githubusercontent.com/github/rest-api-description/refs/heads/main/descriptions/api.github.com/api.github.com.json  -language "typescript" -dev

It fails with this error:

crit: Kiota.Builder.KiotaBuilder[0]
      error generating the client: Function deserializeIntoWithPath not found in namespace app.client.models
      System.InvalidOperationException: Function deserializeIntoWithPath not found in namespace app.client.models
         at Kiota.Builder.Writers.TypeScript.CodeFunctionWriter.FindFunctionInNameSpace(String functionName, CodeElement codeElement, CodeType returnType) in E:\Projekte\Github\kiota\src\Kiota.Builder\Writers\TypeScript\CodeFunctionWriter.cs:line 447
         at Kiota.Builder.Writers.TypeScript.CodeFunctionWriter.GetDeserializerFunctionName(CodeElement codeElement, CodeType returnType) in E:\Projekte\Github\kiota\src\Kiota.Builder\Writers\TypeScript\CodeFunctionWriter.cs:line 436
         at Kiota.Builder.Writers.TypeScript.CodeFunctionWriter.WriteDiscriminatorInformation(CodeFunction codeElement, CodeParameter parseNodeParameter, LanguageWriter writer) in E:\Projekte\Github\kiota\src\Kiota.Builder\Writers\TypeScript\CodeFunctionWriter.cs:line 398
         at Kiota.Builder.Writers.TypeScript.CodeFunctionWriter.WriteFactoryMethodBody(CodeFunction codeElement, String returnType, CodeFile codeFile, LanguageWriter writer) in E:\Projekte\Github\kiota\src\Kiota.Builder\Writers\TypeScript\CodeFunctionWriter.cs:line 357
         at Kiota.Builder.Writers.TypeScript.CodeFunctionWriter.WriteFactoryMethod(CodeFunction codeElement, CodeFile codeFile, LanguageWriter writer) in E:\Projekte\Github\kiota\src\Kiota.Builder\Writers\TypeScript\CodeFunctionWriter.cs:line 342
         at Kiota.Builder.Writers.TypeScript.CodeFunctionWriter.WriteCodeElement(CodeFunction codeElement, LanguageWriter writer) in E:\Projekte\Github\kiota\src\Kiota.Builder\Writers\TypeScript\CodeFunctionWriter.cs:line 121
         at Kiota.Builder.Writers.LanguageWriter.Write[T](T code) in E:\Projekte\Github\kiota\src\Kiota.Builder\Writers\LanguageWriter.cs:line 149
         at Kiota.Builder.CodeRenderers.CodeRenderer.RenderCode(LanguageWriter writer, CodeElement element) in E:\Projekte\Github\kiota\src\Kiota.Builder\CodeRenderers\CodeRenderer.cs:line 83
         at Kiota.Builder.CodeRenderers.CodeRenderer.RenderCode(LanguageWriter writer, CodeElement element) in E:\Projekte\Github\kiota\src\Kiota.Builder\CodeRenderers\CodeRenderer.cs:line 88
         at Kiota.Builder.CodeRenderers.CodeRenderer.RenderCodeNamespaceToSingleFileAsync(LanguageWriter writer, CodeElement codeElement, String outputFile, CancellationToken cancellationToken) in E:\Projekte\Github\kiota\src\Kiota.Builder\CodeRenderers\CodeRenderer.cs:line 35
         at Kiota.Builder.CodeRenderers.CodeRenderer.RenderCodeNamespaceToSingleFileAsync(LanguageWriter writer, CodeElement codeElement, String outputFile, CancellationToken cancellationToken) in E:\Projekte\Github\kiota\src\Kiota.Builder\CodeRenderers\CodeRenderer.cs:line 37
         at Kiota.Builder.CodeRenderers.CodeRenderer.RenderCodeNamespaceToFilePerClassAsync(LanguageWriter writer, CodeNamespace currentNamespace, CancellationToken cancellationToken) in E:\Projekte\Github\kiota\src\Kiota.Builder\CodeRenderers\CodeRenderer.cs:line 55
         at Kiota.Builder.CodeRenderers.CodeRenderer.RenderCodeNamespaceToFilePerClassAsync(LanguageWriter writer, CodeNamespace currentNamespace, CancellationToken cancellationToken) in E:\Projekte\Github\kiota\src\Kiota.Builder\CodeRenderers\CodeRenderer.cs:line 59
         at Kiota.Builder.CodeRenderers.CodeRenderer.RenderCodeNamespaceToFilePerClassAsync(LanguageWriter writer, CodeNamespace currentNamespace, CancellationToken cancellationToken) in E:\Projekte\Github\kiota\src\Kiota.Builder\CodeRenderers\CodeRenderer.cs:line 59
         at Kiota.Builder.CodeRenderers.CodeRenderer.RenderCodeNamespaceToFilePerClassAsync(LanguageWriter writer, CodeNamespace currentNamespace, CancellationToken cancellationToken) in E:\Projekte\Github\kiota\src\Kiota.Builder\CodeRenderers\CodeRenderer.cs:line 59
         at Kiota.Builder.CodeRenderers.CodeRenderer.RenderCodeNamespaceToFilePerClassAsync(LanguageWriter writer, CodeNamespace currentNamespace, CancellationToken cancellationToken) in E:\Projekte\Github\kiota\src\Kiota.Builder\CodeRenderers\CodeRenderer.cs:line 59
         at Kiota.Builder.CodeRenderers.CodeRenderer.RenderCodeNamespaceToFilePerClassAsync(LanguageWriter writer, CodeNamespace currentNamespace, CancellationToken cancellationToken) in E:\Projekte\Github\kiota\src\Kiota.Builder\CodeRenderers\CodeRenderer.cs:line 59
         at Kiota.Builder.CodeRenderers.CodeRenderer.RenderCodeNamespaceToFilePerClassAsync(LanguageWriter writer, CodeNamespace currentNamespace, CancellationToken cancellationToken) in E:\Projekte\Github\kiota\src\Kiota.Builder\CodeRenderers\CodeRenderer.cs:line 59
         at Kiota.Builder.CodeRenderers.CodeRenderer.RenderCodeNamespaceToFilePerClassAsync(LanguageWriter writer, CodeNamespace currentNamespace, CancellationToken cancellationToken) in E:\Projekte\Github\kiota\src\Kiota.Builder\CodeRenderers\CodeRenderer.cs:line 59
         at Kiota.Builder.KiotaBuilder.CreateLanguageSourceFilesAsync(GenerationLanguage language, CodeNamespace generatedCode, CancellationToken cancellationToken) in E:\Projekte\Github\kiota\src\Kiota.Builder\KiotaBuilder.cs:line 668
         at Kiota.Builder.KiotaBuilder.<>c__DisplayClass21_0.<<GenerateClientAsync>b__0>d.MoveNext() in E:\Projekte\Github\kiota\src\Kiota.Builder\KiotaBuilder.cs:line 311
      --- End of stack trace from previous location ---
         at Kiota.Builder.KiotaBuilder.GenerateConsumerAsync(Func`5 innerGenerationSteps, CancellationToken cancellationToken) in E:\Projekte\Github\kiota\src\Kiota.Builder\KiotaBuilder.cs:line 348
         at Kiota.Builder.KiotaBuilder.GenerateConsumerAsync(Func`5 innerGenerationSteps, CancellationToken cancellationToken) in E:\Projekte\Github\kiota\src\Kiota.Builder\KiotaBuilder.cs:line 368
         at Kiota.Builder.KiotaBuilder.GenerateClientAsync(CancellationToken cancellationToken) in E:\Projekte\Github\kiota\src\Kiota.Builder\KiotaBuilder.cs:line 285
         at kiota.Handlers.KiotaGenerateCommandHandler.InvokeAsync(ParseResult parseResult, CancellationToken cancellationToken) in E:\Projekte\Github\kiota\src\kiota\Handlers\KiotaGenerateCommandHandler.cs:line 166

Maybe related to #7802 (same method, but different line)?

[WolfgangHG]

It seems to be caused by this path - when excluding it in "config.json", the code generating works.

   "/repos/{owner}/{repo}/contents/{path}": {
      "get": {
        "summary": "Get repository content",
        "description": "Gets the contents of a file or directory in a repository. Specify ....",
        "tags": [
          "repos"
        ],
        "operationId": "repos/get-content",
        "externalDocs": {
          "description": "API method documentation",
          "url": "https://docs.github.com/rest/repos/contents#get-repository-content"
        },
        "parameters": [
          {
            "$ref": "#/components/parameters/owner"
          },
          {
            "$ref": "#/components/parameters/repo"
          },
          {
            "name": "path",
            "description": "path parameter",
            "in": "path",
            "required": true,
            "schema": {
              "type": "string"
            },
            "x-multi-segment": true
          },
          {
            "name": "ref",
            "description": "The name of the commit/branch/tag. Default: the repository’s default branch.",
            "in": "query",
            "required": false,
            "schema": {
              "type": "string"
            }
          }
        ],

Maybe caused by duplicate "path" as url parameter and in "parameters" block?

[WolfgangHG]

I trimmed down the Github api description to a small reproducer (only one endpoint, only required schemas).
openapi_modified.json

The error is caused by the response, which can have four possible properties and a discriminator.

        "responses": {
          "200": {
            "description": "Response",
            "content": {
              ...
              "application/json": {
                "schema": {
                  "oneOf": [
                    {
                      "$ref": "#/components/schemas/content-directory"
                    },
                    {
                      "$ref": "#/components/schemas/content-file"
                    },
                    {
                      "$ref": "#/components/schemas/content-symlink"
                    },
                    {
                      "$ref": "#/components/schemas/content-submodule"
                    }
                  ],
                  "discriminator": {
                    "propertyName": "type",
                    "mapping": {
                      "array": "#/components/schemas/content-directory",
                      "file": "#/components/schemas/content-file",
                      "symlink": "#/components/schemas/content-symlink",
                      "submodule": "#/components/schemas/content-submodule"
                    }
                  }
                },

The discriminator value "array" is not handled properly, it does not create a schema class "ContentDirectory" which is just an array of objects.

I am out now - though debugging it, I don't see whats going wrong here ;-).

[WolfgangHG]

Followup typescript error after having excluded the path the causes the Kiota error: #7862