WebAssembly should support handling runtimeconfig.json

[akoeplinger]

See #37535 (comment)

[marek-safar]

Could you clarify why? We'd need to copy the files to the temp file system and add all the baggage for handling the json logic which is not necessary for self-contained setup.

I think a better approach is to add the configProperties section which is probably the only relevant part for self-contained configs to csproj PropertyGroup and handle it during build.

[akoeplinger]

Yeah I was imprecise when creating the title, I don't think we need to necessarily read the file as part of the WASM process but we need to handle it somehow rather than just ignoring it.

[radical]

I think a better approach is to add the configProperties section which is probably the only relevant part for self-contained configs to csproj PropertyGroup and handle it during build.

Do you mean - read the configProperties section of the runtimeConfig.json, and add it to the build, so that we don't have to support reading runtimeConfig.json itself in the wasm app?

[marek-safar]

We should just leverage the runtimeConfig.json task we have for mobile AOT for WASM AOT

[lambdageek]

Yea, this is exactly what the runtimeConfig.json task is meant to do. The WasmApp target needs to be updated to use it, and then driver.c needs to be updated to call the runtime API that consumes the binary blob of the parsed json file.

[SamMonoRT]

cc @lewing @radical - Fan will give this a shot.

[eerhardt]

Is this going to be completed for .NET 6? Using AppContext switches is becoming more and more important in order to support feature switches. For example, the plan in #55102 is relying on the fact that an AppContext switch will be set in applications that will be trimmed during F5/dotnet run.

[SamMonoRT]

Is this going to be completed for .NET 6? Using AppContext switches is becoming more and more important in order to support feature switches. For example, the plan in #55102 is relying on the fact that an AppContext switch will be set in applications that will be trimmed during F5/dotnet run.

Yes, a PR should be up soon