Regression from 13.6.2 to 13.7.0

A SwaggerException is generated in the C# client when upgrading from 13.6.2 to 13.7.0 Beware that the entity returned contains types like enums, DateTime?, byte…

How can I determine what field is failing?

Sample method OK 13.6.2

        public async System.Threading.Tasks.Task<Asset> GetAssetAsync(int assetId, int? version, System.Threading.CancellationToken cancellationToken = default(System.Threading.CancellationToken))
        {
            if (assetId == null)
                throw new System.ArgumentNullException("assetId");
    
            var urlBuilder_ = new System.Text.StringBuilder();
            urlBuilder_.Append(BaseUrl != null ? BaseUrl.TrimEnd('/') : "").Append("/api/Asset/GetAsset?");
            urlBuilder_.Append(System.Uri.EscapeDataString("assetId") + "=").Append(System.Uri.EscapeDataString(ConvertToString(assetId, System.Globalization.CultureInfo.InvariantCulture))).Append("&");
            urlBuilder_.Append(System.Uri.EscapeDataString("version") + "=").Append(System.Uri.EscapeDataString(version != null ? ConvertToString(version, System.Globalization.CultureInfo.InvariantCulture) : "")).Append("&");
            urlBuilder_.Length--;
    
            var client_ = await CreateHttpClientAsync(cancellationToken).ConfigureAwait(false);
            try
            {
                using (var request_ = await CreateHttpRequestMessageAsync(cancellationToken).ConfigureAwait(false))
                {
                    request_.Method = new System.Net.Http.HttpMethod("GET");
                    request_.Headers.Accept.Add(System.Net.Http.Headers.MediaTypeWithQualityHeaderValue.Parse("application/json"));
    
                    PrepareRequest(client_, request_, urlBuilder_);
                    var url_ = urlBuilder_.ToString();
                    request_.RequestUri = new System.Uri(url_, System.UriKind.RelativeOrAbsolute);
                    PrepareRequest(client_, request_, url_);
    
                    var response_ = await client_.SendAsync(request_, System.Net.Http.HttpCompletionOption.ResponseHeadersRead, cancellationToken).ConfigureAwait(false);
                    try
                    {
                        var headers_ = System.Linq.Enumerable.ToDictionary(response_.Headers, h_ => h_.Key, h_ => h_.Value);
                        if (response_.Content != null && response_.Content.Headers != null)
                        {
                            foreach (var item_ in response_.Content.Headers)
                                headers_[item_.Key] = item_.Value;
                        }
    
                        ProcessResponse(client_, response_);
    
                        var status_ = ((int)response_.StatusCode).ToString();
                        if (status_ == "200") 
                        {
                            var objectResponse_ = await ReadObjectResponseAsync<Asset>(response_, headers_).ConfigureAwait(false);
                            return objectResponse_.Object;
                        }
                        else
                        if (status_ != "200" && status_ != "204")
                        {
                            var responseData_ = response_.Content == null ? null : await response_.Content.ReadAsStringAsync().ConfigureAwait(false); 
                            throw new SwaggerException("The HTTP status code of the response was not expected (" + (int)response_.StatusCode + ").", (int)response_.StatusCode, responseData_, headers_, null);
                        }
            
                        return default(Asset);
                    }
                    finally
                    {
                        if (response_ != null)
                            response_.Dispose();
                    }
                }
            }
            finally
            {
                if (client_ != null)
                    client_.Dispose();
            }
        }

...

 [System.CodeDom.Compiler.GeneratedCode("NJsonSchema", "10.1.11.0 (Newtonsoft.Json v12.0.0.0)")]
    public partial class Asset : System.ComponentModel.INotifyPropertyChanged
    {
        private int _id;
        private string _code;
        private decimal _sortSequence;
        private byte _pointsPlaces;
        private bool _quoteBasis;
        private int? _nDFFixDays;
        private ForwardCodeTypeEnum _forwardCodeType;
        private AssetStatus _statusCodeId;
        private System.DateTime _createdDate;
        private System.DateTime? _authorisedDate;
        private Risk _risk;
...
        private TechOverrideMask _techOverrideMask;
        private System.Collections.ObjectModel.ObservableCollection<AssetRegion> _assetRegions; 
        private System.Collections.ObjectModel.ObservableCollection<string> _currentChanges;
    ...
        [Newtonsoft.Json.JsonProperty("Id", Required = Newtonsoft.Json.Required.DisallowNull, NullValueHandling = Newtonsoft.Json.NullValueHandling.Ignore)]
        public int Id
        {
            get { return _id; }
            set 
            {
                if (_id != value)
                {
                    _id = value; 
                    RaisePropertyChanged();
                }
            }
        }
    ...

Sample method failing 13.7.0

     public async System.Threading.Tasks.Task<Asset> GetAssetAsync(int assetId, int? version, System.Threading.CancellationToken cancellationToken = default(System.Threading.CancellationToken))
        {
            if (assetId == null)
                throw new System.ArgumentNullException("assetId");
    
            var urlBuilder_ = new System.Text.StringBuilder();
            urlBuilder_.Append(BaseUrl != null ? BaseUrl.TrimEnd('/') : "").Append("/api/Asset/GetAsset?");
            urlBuilder_.Append(System.Uri.EscapeDataString("assetId") + "=").Append(System.Uri.EscapeDataString(ConvertToString(assetId, System.Globalization.CultureInfo.InvariantCulture))).Append("&");
            urlBuilder_.Append(System.Uri.EscapeDataString("version") + "=").Append(System.Uri.EscapeDataString(version != null ? ConvertToString(version, System.Globalization.CultureInfo.InvariantCulture) : "")).Append("&");
            urlBuilder_.Length--;
    
            var client_ = await CreateHttpClientAsync(cancellationToken).ConfigureAwait(false);
            try
            {
                using (var request_ = await CreateHttpRequestMessageAsync(cancellationToken).ConfigureAwait(false))
                {
                    request_.Method = new System.Net.Http.HttpMethod("GET");
                    request_.Headers.Accept.Add(System.Net.Http.Headers.MediaTypeWithQualityHeaderValue.Parse("application/json"));
    
                    PrepareRequest(client_, request_, urlBuilder_);
                    var url_ = urlBuilder_.ToString();
                    request_.RequestUri = new System.Uri(url_, System.UriKind.RelativeOrAbsolute);
                    PrepareRequest(client_, request_, url_);
    
                    var response_ = await client_.SendAsync(request_, System.Net.Http.HttpCompletionOption.ResponseHeadersRead, cancellationToken).ConfigureAwait(false);
                    try
                    {
                        var headers_ = System.Linq.Enumerable.ToDictionary(response_.Headers, h_ => h_.Key, h_ => h_.Value);
                        if (response_.Content != null && response_.Content.Headers != null)
                        {
                            foreach (var item_ in response_.Content.Headers)
                                headers_[item_.Key] = item_.Value;
                        }
    
                        ProcessResponse(client_, response_);
    
                        var status_ = (int)response_.StatusCode;
                        if (status_ == 200)
                        {
                            var objectResponse_ = await ReadObjectResponseAsync<Asset>(response_, headers_).ConfigureAwait(false);
                            return objectResponse_.Object;
                        }
                        else
                        {
                            var responseData_ = response_.Content == null ? null : await response_.Content.ReadAsStringAsync().ConfigureAwait(false); 
                            throw new SwaggerException("The HTTP status code of the response was not expected (" + status_ + ").", status_, responseData_, headers_, null);
                        }
                    }
                    finally
                    {
                        if (response_ != null)
                            response_.Dispose();
                    }
                }
            }
            finally
            {
                if (client_ != null)
                    client_.Dispose();
            }
        }
    
...


    [System.CodeDom.Compiler.GeneratedCode("NJsonSchema", "10.1.24.0 (Newtonsoft.Json v12.0.0.0)")]
    public partial class Asset : System.ComponentModel.INotifyPropertyChanged
    {
        private int _id;
  ...  

[augustoproiete]

C# is C#, and you can’t return two totally unrelated types from your methods

Hey @jeremyVignelles whilst I agree with your statement in general, I believe that’s not really what’s being asked here.

What I think we’re all looking for, myself included (and @mattwhitfield, correct me if I’m wrong) is for the NSwag client generator to understand null (for nullable types of course) when the response HTTP status code is 204.

As @mattwhitfield described in his scenario, his API either returns 202 with an entity, or 204 without an entity.

Right now, the API client throws an exception on 204 rather than returning null to the caller. This should be possible. If not the default option, it should at least be configurable.

[jeremyVignelles]

Thanks @mattwhitfield for your detailed answer. I agree that NSwag should not have to make any decision for those kind of cases, but C# is C#, and you can’t return two totally unrelated types from your methods.

The default behavior there will be that NSwag will pick one result as the return type, but the other one will throw, which is not consistent with the fact that this is also a success.

That said, for these kind of use cases, I’d advise that you use the WrapDTO option which should be able to do just that, though I didn’t test it myself.