.NET Minimal API proper use of .AddJsonFile() with environment variables

Question

I see .NET samples with, for example,

builder.Configuration
    .AddJsonFile("appsettings.json", optional: false, reloadOnChange: true)
    .AddJsonFile($"appsettings{builder.Environment.EnvironmentName}.json", optional: true, reloadOnChange: true);

But in this article: https://learn.microsoft.com/en-us/aspnet/core/fundamentals/configuration/?view=aspnetcore-7.0 it says of that code:

"Settings in the MyConfig.json file override setting in the default configuration providers, including the Environment variables configuration provider and the Command-line configuration provider."

So does that mean:

1. That you should just be aware, and be careful not to override values from environment variables

2. That you now need to also explicitly read environment variables?

For example, I also see this pattern in sample code:

builder.Configuration
    .AddJsonFile("appsettings.json", optional: false, reloadOnChange: true)       
    .AddJsonFile($"appsettings{builder.Environment.EnvironmentName}.json", optional: true, reloadOnChange: true);
    .AddEnvironmentVariables();

I assume that it's #1. Obviously I could test this, but figured that I could save myself and others the trouble by asking.

Answer 1

Not exactly, settings in the JSON file override all other providers because it is the only provider configured.

When you append an environment setting provider at the end:

builder.Configuration
    .AddJsonFile("appsettings.json", optional: false, reloadOnChange: true)       
    .AddJsonFile($"appsettings{builder.Environment.EnvironmentName}.json", optional: true, reloadOnChange: true);
    .AddEnvironmentVariables();

Then, this means JSON settings can be overridden by environment variables because it is the last one declared in code. Basically I think what the docs are trying to say is the order in which you declare your settings providers matters. So it all depends on what you are trying to achieve.