Could not parse the JSON file

[beefsteak]

1.Create new worker service project.
2.Debug is error, but run is right.

[scalablecory]

what does your json file look like?

[beefsteak]

@scalablecory

[beefsteak]

@scalablecory All net core projects that contain the appsetting file report the same error.

[beefsteak]

@scalablecory But running without debugging does not cause errors

[davidfowl]

Looks like a BOM problem. Did this happen by default?

[beefsteak]

yes，it happen by default

[beefsteak]

Appseting.json default format is utf-8

[beefsteak]

@scalablecory Does this error have anything to do with net core built-in system.text.json component

[beefsteak]

@scalablecory That's fine if project sdk is net core 2.2. So my guess is that net core 3.0 caused the problem

[scalablecory]

Thanks for the detail. We'll need to take a look at the file to know for sure, but it's possible.

[scalablecory]

@davkean @Pilchie possible VS template or appsettings parser issue, can you help route this to the right people?

[Pilchie]

if it's templates, that would depend on the exact template. If it's System.Text.Json then corefx. @ahsonkhan for S.T.J...

[ahsonkhan]

I tried to repro the issue on .NET Core 3.0 and couldn't (TFM netcoreapp3.0 with <PackageReference Include="Microsoft.Extensions.Hosting" Version="3.0.0" />). Same with .NET Core 3.1 (even if I explicitly save the appsettings json file to UTF-8 with BOM).

@beefsteak, can you share a copy of your project that is showing the error?
What version of VS are you using?

When I create a new worker service (using VS Version 16.4.0 Preview 3.0), the appsettings.json file doesn't contain a BOM so I don't see why the file you are seeing would start with a 0xEF byte.

There was a BOM issue with the JsonSerializer that was fixed for 3.1 (that is if the JSON file did contain a BOM marker), but I can't tell if that is relevant here without a repro:
https://github.com/dotnet/corefx/issues/42145

[beefsteak]

Please see the attachment for the project
WorkerService1.zip