Compiler errors in C# client generated code when request has a List<T> as path parameter

[fretje]

I have a request that takes List<Guid> as a path parameter.

And there's code in the generated client that doesn't compile.

This is the signature of the generated client method:

public virtual System.Threading.Tasks.Task<System.Collections.Generic.ICollection<string>> GetSomethingAsync(System.Collections.Generic.IEnumerable<System.Guid> input)

This is the piece of code that doesn't compile (it's the piece that builds the input parameter for the url):

for (var i = 0; i < input.Length; i++)
{
    if (i > 0) urlBuilder_.Append(',');
    urlBuilder_.Append(ConvertToString(input[i], System.Globalization.CultureInfo.InvariantCulture));
}

The compiler errors are:

1>error CS1061: 'IEnumerable<Guid>' does not contain a definition for 'Length' and no accessible extension method 'Length' accepting a first argument of type 'IEnumerable<Guid>' could be found (are you missing a using directive or an assembly reference?)
1>error CS0021: Cannot apply indexing with [] to an expression of type 'IEnumerable<Guid>'

This used to work fine in preview10, but doesn't anymore in the released v14.

For reference, this is the working generated code that was in preview10:

urlBuilder_.Append(System.Uri.EscapeDataString(string.Join(",", System.Linq.Enumerable.Select(input, s_ => ConvertToString(s_, System.Globalization.CultureInfo.InvariantCulture)))));

[fretje]

This change is the culprit apparently:

9175311#diff-416f8759e9ce0cecba7578a64bf1fc4b9fee9325d331641eaf7b07d62e7455bbR18-R22

Not sure where exactly the bug is here though...

is it parameter.IsArray that wrongfully returns true?
or shouldn't this code use parameter.IsArray? I see in other parts that the code checks for xxx.GetType().IsArray, which is another kind of "IsArray" (the c# array type vs openapi array type)

[braulstonos]

I'm running into this exact same issue with NSwag 14

[MortenMeisler]

Same here.

Controller method:

[HttpGet]
[Route("getsomething/{Ids}")]
public async Task<IEnumerable<string>> GetSomething(IList<string> Ids)
{
    var somethings = await _accountService.GetSomething(Ids).ConfigureAwait(false);
    return somethings ;
}

Generates:

public virtual async System.Threading.Tasks.Task<System.Collections.Generic.ICollection<string>> Account_GetSomethingAsync(System.Collections.Generic.IEnumerable<string> IdsPath, System.Collections.Generic.IEnumerable<string> IdsBody, System.Threading.CancellationToken cancellationToken)
{
    if (IdsPath == null)
        throw new System.ArgumentNullException("IdsPath");

    if (IdsBody == null)
        throw new System.ArgumentNullException("IdsBody");

    var client_ = _httpClient;
    var disposeClient_ = false;
    try
    {
        using (var request_ = new System.Net.Http.HttpRequestMessage())
        {
            var json_ = Newtonsoft.Json.JsonConvert.SerializeObject(IdsBody, _settings.Value);
            var content_ = new System.Net.Http.StringContent(json_);
            content_.Headers.ContentType = System.Net.Http.Headers.MediaTypeHeaderValue.Parse("application/json");
            request_.Content = content_;
            request_.Method = new System.Net.Http.HttpMethod("GET");
            request_.Headers.Accept.Add(System.Net.Http.Headers.MediaTypeWithQualityHeaderValue.Parse("application/json"));

            var urlBuilder_ = new System.Text.StringBuilder();
        
            // Operation Path: "api/Account/getsomething/{Ids}"
            urlBuilder_.Append("api/Account/getsomething/");
            for (var i = 0; i < IdsPath.Length; i++)
            {
                if (i > 0) urlBuilder_.Append(',');
                urlBuilder_.Append(ConvertToString(IdsPath[i], System.Globalization.CultureInfo.InvariantCulture));
            }

// etc. ....

I get error at Length and indexing [i]

[braulstonos]

Still exists in 14.0.1

[MortenMeisler]

You would expect some unit test would break here right?

[braulstonos]

Any idea when this will be addressed?

[MortenMeisler]

@RicoSuter friendly bump. List arguments does not work at the moment

[jake-carpenter]

I have created a reproduction here: https://github.com/jake-carpenter/nswag-4672-repro