JsonSerializerOptionsNoTypeInfoResolverSpecified after upgrading from .NET 8 Preview 6 to 7 (release mode only)

[DM-98]

Description

App works fine in debug mode for both Preview 6 and 7.
App crashes in release mode for just Preview 7: JsonSerializerOptionsNoTypeInfoResolverSpecified.

My app worked fine in .NET 8 Preview 6:

After upgrading to .NET 8 Preview 7:

Seems like a JsonSerializer bug in the .NET Preview 7 install package. I tried these:

• Keeping same codebase, but changing from 6 to 7 and back to 6 to confirm the issue
• Changing JsonSerializer to JsonConvert, issue persists
• Creating my own JsonSerializerContext class using the attributes and applying it as my TypeInfoResolver for the JsonSerializerOptions: [JsonSourceGenerationOptions] & [JsonSerializable(typeof(MySerializableType))], then the error changes to NoMetadataSpecified or something like that
• Removed JsonSerializerOptions entirely in my code, issue persists
• Used PostAsync instead of PostAsJsonAsync, issue persists

Steps to Reproduce

1. Create an API with a HttpPost endpoint that accepts a complex object in body
2. Create a MAUI app that runs on .NET 8 Preview 7 (dotnet workload install maui)
3. Call the API endpoint with a Post request using PostAsJsonAsync method
4. Run the app in Release mode using .NET 8 Preview 7

Link to public reproduction project repository

https://github.com/DM-98/MauiApp1

Version with bug

8.0.0-preview.7.8842

Is this a regression from previous behavior?

Yes, this used to work in .NET MAUI

Last version that worked well

8.0.0-preview.6.8686

Affected platforms

Android, I was not able test on other platforms

Affected platform versions

Android 13, not tested on other.

Did you find any workaround?

Change back to previous SDK: .NET 8 Preview 6.
Edit (workaround by eiriktsarpalis):

Appears to be a duplicate of dotnet/maui#16038. Setting

<JsonSerializerIsReflectionEnabledByDefault>true</JsonSerializerIsReflectionEnabledByDefault>

in your project should get you back the original behavior.

Relevant log output

No response

[ghost]

Tagging subscribers to this area: @dotnet/area-system-text-json, @gregsdennis
See info in area-owners.md if you want to be subscribed.

Issue Details

---

Description

App works fine in debug mode for both Preview 6 and 7.
App crashes in release mode for just Preview 7: JsonSerializerOptionsNoTypeInfoResolverSpecified.

Codebase:

private readonly HttpClient httpClient;
private readonly JsonSerializerOptions jsonSerializerOptions;

public HttpClientDocumentService(HttpClient httpClient)
{
	this.httpClient = httpClient;
	jsonSerializerOptions = new JsonSerializerOptions(JsonSerializerDefaults.Web);
}

public async Task<ResponseDTO<IReadOnlyCollection<DocumentListDTO>>> GetDocumentListAsync(DocumentFilter documentFilter, CancellationToken cancellationToken = default)
{
	try
	{
		HttpResponseMessage response = await httpClient.PostAsJsonAsync("Document/GetDocumentList", documentFilter, jsonSerializerOptions, cancellationToken);

		return await response.Content.ReadFromJsonAsync<ResponseDTO<IReadOnlyCollection<DocumentListDTO>>>(jsonSerializerOptions, cancellationToken) ?? new ResponseDTO<IReadOnlyCollection<DocumentListDTO>>(false, "Der skete en serverfejl, kontakt os hvis problemet fortsætter.");
	}
	catch (OperationCanceledException ex)
	{
		return new ResponseDTO<IReadOnlyCollection<DocumentListDTO>>(false, "Din anmodning blev annulleret.", ErrorType.General_OperationCanceled, ex.Message, ex.InnerException?.Message);
	}
	catch (Exception ex)
	{
		return new ResponseDTO<IReadOnlyCollection<DocumentListDTO>>(false, "Der opstod en fejl ved din behandling - prøv igen eller kontakt os.", ErrorType.General_Unhandled, ex.Message, ex.InnerException?.Message);
	}
}

My app worked fine in .NET 8 Preview 6:

After upgrading to .NET 8 Preview 7:

Seems like a JsonSerializer bug in the .NET Preview 7 install package. I tried these:

• Keeping same codebase, but changing from 6 to 7 and back to 6 to confirm the issue
• Changing JsonSerializer to JsonConvert, issue persists
• Creating my own JsonSerializerContext class using the attributes and applying it as my TypeInfoResolver for the JsonSerializerOptions: [JsonSourceGenerationOptions] & [JsonSerializable(typeof(MySerializableType))], then the error changes to NoMetadataSpecified or something like that
• Removed JsonSerializerOptions entirely in my code, issue persists
• Used PostAsync instead of PostAsJsonAsync, issue persists

Steps to Reproduce

1. Create an API with a HttpPost endpoint that accepts a complex object in body
2. Create a MAUI app that runs on .NET 8 Preview 7 (dotnet workload install maui)
3. Call the API endpoint with a Post request using PostAsJsonAsync method
4. Run the app in Release mode using .NET 8 Preview 7

Link to public reproduction project repository

No response

Version with bug

8.0.0-preview.7.8842

Is this a regression from previous behavior?

Yes, this used to work in .NET MAUI

Last version that worked well

8.0.0-preview.6.8686

Affected platforms

Android, I was not able test on other platforms

Affected platform versions

Android 13, not tested on other.

Did you find any workaround?

Change back to previous SDK: .NET 8 Preview 6.

Relevant log output

No response

Author:	DM-98
Assignees:	-
Labels:	area-System.Text.Json
Milestone:	-

[eiriktsarpalis]

Appears to be a duplicate of dotnet/maui#16038. Setting

<JsonSerializerIsReflectionEnabledByDefault>true</JsonSerializerIsReflectionEnabledByDefault>

in your project should get you back the original behavior.

[DM-98]

@eiriktsarpalis That worked, thanks. When will this be fixed, and after fix can I remove that line? in .NET 8 RC1?

[eiriktsarpalis]

@DM-98 I would recommend subscribing to dotnet/maui#16038 for updates on the issue.