Cannot deserialize BrowseResult (and others) due to no default constructor

[mattjhosking]

This occurs when calling BrowseArtistReleasesAsync - could this have occurred due to shifting to System.Text.Json? Newtonsoft is much more forgiving in this and a number of other cases. Either a a converter will be needed to create the classes successfully, or default constructors added to all classes that need to support JSON deserialization.

[Zastai]

Could you add an example method call and the stack trace of the exception?
I wrote custom converters for maximum flexibility (and slightly better speed). I may have neglected to register one of the converters

[mattjhosking]

        public async Task<ArtistRelease[]> RetrieveReleases(Guid artistId)
        {
            var searchResult = await new Query("Dev Test", "1.0", "matt.j.hosking@gmail.com").BrowseArtistReleasesAsync(artistId).ConfigureAwait(false);
            return searchResult.Results
                .Select(x => new ArtistRelease { Title = x.Title, Year = x.Date?.Year })
                .ToArray();
        }

System.NotSupportedException
HResult=0x80131515
Message=Deserialization of reference types without parameterless constructor is not supported. Type 'MetaBrainz.MusicBrainz.Objects.Browses.BrowseResult'
Source=System.Text.Json
StackTrace:
at System.Text.Json.ThrowHelper.ThrowNotSupportedException_DeserializeCreateObjectDelegateIsNull(Type invalidType)
at System.Text.Json.JsonSerializer.HandleStartObject(JsonSerializerOptions options, ReadStack& state)
at System.Text.Json.JsonSerializer.ReadCore(JsonSerializerOptions options, Utf8JsonReader& reader, ReadStack& readStack)
at System.Text.Json.JsonSerializer.ReadCore(Type returnType, JsonSerializerOptions options, Utf8JsonReader& reader)
at System.Text.Json.JsonSerializer.Deserialize(String json, Type returnType, JsonSerializerOptions options)
at System.Text.Json.JsonSerializer.Deserialize[TValue](String json, JsonSerializerOptions options)
at MetaBrainz.Common.Json.JsonUtils.Deserialize[T](String json, JsonSerializerOptions options)
at MetaBrainz.MusicBrainz.Query.Deserialize[T](String json)
at MetaBrainz.MusicBrainz.Objects.Browses.BrowseResults1.Deserialize(String json) at MetaBrainz.MusicBrainz.Objects.PagedQueryResults3.d__12.MoveNext()
at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
at System.Runtime.CompilerServices.ConfiguredTaskAwaitable`1.ConfiguredTaskAwaiter.GetResult()
at xxxxxx.Music.Services.MusicBrainz.MusicBrainzArtistRepository.d__2.MoveNext() in C:\Dev\xxxxxx.Music\xxxxxx.Music.Services\MusicBrainz\MusicBrainzArtistRepository.cs:line 26

This exception was originally thrown at this call stack:
[External Code]
xxxxxx.Music.Services.MusicBrainz.MusicBrainzArtistRepository.RetrieveReleases(System.Guid) in MusicBrainzArtistRepository.cs

[Zastai]

Thanks. For future reference, it's generally useful to provide the parameter values too - often a bug is specific to a combination of entities.
In this case, I was able to reproduce the crash, so that won't be needed. Will look at later after work is finished. (But it's Microsoft Build too, so I may not have a huge amount of free time.)

Side note: if it's feasible in your code, I would recommend creating longer-lived Query objects, instead of creating a new one per request, especially if you are likely to have a large volume of requests.

[mattjhosking]

Thanks @Zastai and noted. Let me know if you need anything else or I could look into it as well if that helps.

[Zastai]

Pushed a fix; could you see whether this resolves your issue? If it does, I'll push a new release package later today.

[mattjhosking]

That's fixed it, thanks!