Add OOTB support for appsettings using JSON5

[mu88]

Is there an existing issue for this?

• I have searched the existing issues

Is your feature request related to a problem? Please describe the problem.

It's not uncommon that one wants to add comments to appsettings*.json. Even the official ASP.NET Core docs contain such examples (see here):

{
  // This file is not imported as a snippet so can be changed for testing.
  ...left out for brevity

But since the official JSON standard does not allow to use comments, this leads to schema validation errors in IDEs like JetBrains Rider:

Describe the solution you'd like

JSON5 is a well-adopted standard that extends JSON with comments. In contrast to JSONC, there is a proper specification (see here). But when renaming appsettings.json to appsettings.json5, neither a .NET CLI nor ASP.NET Core app picks up this config file anymore.
Of course, one could manually add them via config.AddJsonFile("appsettings.json5"); - but then you also have to add config.AddJsonFile($"appsettings.{env.EnvironmentName}.json5") for the environment-specific stuff.

Since JSON5 seems like a mature standard to me, I suggest adding OOTB support for appsettings*.json5. So far, I found the following spots:

ASP.NET Core

Sources

Current

        configuration.AddJsonFile("appsettings.json", optional: true, reloadOnChange: reloadOnChange)
            .AddJsonFile($"appsettings.{env.EnvironmentName}.json", optional: true, reloadOnChange: reloadOnChange);

New

        configuration.AddJsonFile("appsettings.json", optional: true, reloadOnChange: reloadOnChange)
            .AddJsonFile($"appsettings.{env.EnvironmentName}.json", optional: true, reloadOnChange: reloadOnChange)
            .AddJsonFile($"appsettings.json5", optional: true, reloadOnChange: reloadOnChange)
            .AddJsonFile($"appsettings.{env.EnvironmentName}.json5", optional: true, reloadOnChange: reloadOnChange);

.NET runtime

Sources

Current

            appConfigBuilder.AddJsonFile("appsettings.json", optional: true, reloadOnChange: reloadOnChange)
                    .AddJsonFile($"appsettings.{env.EnvironmentName}.json", optional: true, reloadOnChange: reloadOnChange);

New

            appConfigBuilder.AddJsonFile("appsettings.json", optional: true, reloadOnChange: reloadOnChange)
                    .AddJsonFile($"appsettings.{env.EnvironmentName}.json", optional: true, reloadOnChange: reloadOnChange)
                    .AddJsonFile($"appsettings.json5", optional: true, reloadOnChange: reloadOnChange)
                    .AddJsonFile($"appsettings.{env.EnvironmentName}.json5", optional: true, reloadOnChange: reloadOnChange);

Additional context

No response

[martincostello]

Looks like this issue should be transferred to dotnet/runtime as that's where the configuration providers are defined.

[mu88]

@martincostello: is this something that I can easily do?

[martincostello]

Either close this issue and open a new one there, or wait until a member of the ASP.NET Core team that has the appropriate permissions transfers this issue there.