Argument null exception

[netpirates]

Describe the bug
While trying to generate C# file from openAPI spec it's throwing error with "System.ArgumentException: String cannot be of zero length". I see same behavior with VS 2019 and 2022 extensions. I'm using VS 2022 on Win 11.
I was able to generate code with same json spec/file earlier using OpenAPI tool which I had it installed in my Win 10 machine using VS 2019. Now I'm not able to generate the file.

Below is is my error:
Parameter name: oldValue
at System.String.ReplaceInternal(String oldValue, String newValue)
at System.String.Replace(String oldValue, String newValue)
at Rapicgen.Core.Generators.OpenApi.OpenApiCSharpCodeGenerator.GenerateCode(IProgressReporter pGenerateProgress) in D:\a\apiclientcodegen\apiclientcodegen\src\Core\ApiClientCodeGen.Core\Generators\OpenApi\OpenApiCSharpCodeGenerator.cs:line 84
at Rapicgen.CustomTool.SingleFileCodeGenerator.Generate(String wszInputFilePath, String bstrInputFileContents, String wszDefaultNamespace, IntPtr[] rgbOutputFileContents, UInt32& pcbOutput, IVsGeneratorProgress pGenerateProgress)
5/18/2025 11:08:27 PM: System.ArgumentException: String cannot be of zero length.

I'm using OpenAPI Generator(V7.13.0) in both VS 2022 and 2019.

Expected behavior
A clear and concise description of what you expected to happen.

Screenshots
If applicable, add screenshots to help explain your problem.

Visual Studio Extension (please complete the following information):

• Visual Studio Version: [e.g. 2017, 2019, Visual Studio for Mac]
• Extension Version [e.g. 1.2.6222]

Additional context
Add any other context about the problem here.

[christianhelle]

@netpirates Thanks for taking the time to report this. Let me see what I can do

[netpirates]

Any update on the issue? Also why in this api client version I'm not able provide json file spec downloaded from the app itself.

[christianhelle]

No updates yet @netpirates. I only work on this in the evenings (CET) after the family goes to bed

[netpirates]

Hi, I see an update pushed for this issue. But still issue is not resolved. I can see the error with updated version also. Not able to generate with OpenAPI or NSWAG. both are throwing different errors. I posted error message with OpenAPI spec in other thread.

With NSwag it's throwing error on Newtonsoft.Json. I have the version 13.0.3 already part of the project.

6/8/2025 11:08:11 AM: Checking required dependencies
6/8/2025 11:08:12 AM: System.IO.FileNotFoundException: Could not load file or assembly 'Newtonsoft.Json, Version=13.0.0.0, Culture=neutral, PublicKeyToken=30ad4fe6b2a6aeed' or one of its dependencies. The system cannot find the file specified.
File name: 'Newtonsoft.Json, Version=13.0.0.0, Culture=neutral, PublicKeyToken=30ad4fe6b2a6aeed'
at NSwag.OpenApiDocument.d__58.MoveNext()
at System.Runtime.CompilerServices.AsyncTaskMethodBuilder1.Start[TStateMachine](TStateMachine& stateMachine) at NSwag.OpenApiDocument.FromJsonAsync(String data, String documentPath, SchemaType expectedSchemaType, Func2 referenceResolverFactory, CancellationToken cancellationToken)
at NSwag.OpenApiDocument.d__59.MoveNext()

[christianhelle]

@netpirates I could never really re-produce this error but the stack trace makes sense and the issue might be resolved in PR #1163

The NSwag error regarding Newtonsoft.Json is a different problem. I haven't seen that in a while