DateOnly not rendering correctly in Swagger

[mattjohnsonpint]

I think this may be a regression of #2319, but in investigating this stackoverflow question, I found that DateOnly fields are still not showing correctly in the Swagger UI in ASP.NET 8 latest.

To reproduce:

• Download and install .NET 8 SDK 8.0.2 (SDK 8.0.201)
• dotnet new webapi
• dotnet run
• Browse to Swagger endpoint, i.e. http://localhost:5261/swagger

Notice DateOnly and DayOfWeek have been broken out into properties as if custom types, rather than being a date.

Apply the workaround:

builder.Services.AddSwaggerGen(options => {
    options.MapType<DateOnly>(() => new OpenApiSchema { 
        Type = "string",
        Format = "date" });
});

Then it works:

This shouldn't be necessary though, right?

Also experiancing this with Controllers, when I tried upgrading to Swashbuckle.AspNetCore 6.5.0 to fix DateOnly serialisation fixed in #2319 but the Swagger.json broke with missing elements so I had to revert back to Swashbuckle.AspNetCore 6.4.0.

Test

1. Create a new Controller API project using the default template.
2. Upgrade to Swashbuckle.AspNetCore 6.5.0.
3. Enable IncludeXmlComments and wire it up.
4. Run project and notice WeatherForecast no longer shows up in the SwaggerUI schema section.

dotnet --version
8.0.200

[martincostello]

We should probably make a copy of WeatherForecast and add it to our integration tests, as it seems to come up often as the repro for issues 😄

[martincostello]

Looks like this will be resolved by #2799.

[vierlijner]

TimeOnly also not for me. The config.MapType<TimeOnly>(() => new OpenApiSchema { Type = "string", Format = "time" }); also won't fix this in AddSwaggerGen.

I expect "14:32:55.348".

Maybe: https://learn.microsoft.com/en-us/dotnet/standard/datetime/how-to-use-dateonly-timeonly#serialize-dateonly-and-timeonly-types

[martincostello]

#2799 and #2804 should fix this issue.