Bug: MinimumLevel override ignores `SourceContext` of LogEvent

The MinimumLevel override does not consider the SourceContext property defined in a LogEvent.

Repro:

Log.Logger = new LoggerConfiguration()
    .MinimumLevel.Verbose()
    .MinimumLevel.Override("MyContext", LogEventLevel.Information)
    .WriteTo.Console()
    .CreateLogger();

// Correct: DOES NOT write to sink, as expected
Log.ForContext(Serilog.Core.Constants.SourceContextPropertyName, "MyContext")
    .Verbose("If you see this, something is wrong (1)");

// Incorrect: DOES WRITE to sink
if (Log.Logger.BindMessageTemplate("If you see this, something is wrong (2)",
    propertyValues: null, out var parsedTemplate, out _))
{
    var properties = new[]
    {
        new LogEventProperty(Serilog.Core.Constants.SourceContextPropertyName,
            new ScalarValue("MyContext")),
    };

    var logEvent = new LogEvent(DateTimeOffset.Now, LogEventLevel.Verbose,
        exception: null, parsedTemplate, properties);

    // DOES WRITE to sink, but *NOT* expected
    Log.Write(logEvent);
}

---

Repro full project:

• ReproSerilogMinimumLevelOverride.zip

Tested:

• Serilog v2.9.0
• .NET Core 3.0 app

[augustoproiete]

I just saw this post on StackOverflow, and it seems the current behavior also affects sub-loggers:

var outputTemplate = "[{Level:u3}] {SourceContext}: {Message:lj}{NewLine}";

Log.Logger = new LoggerConfiguration()
    .MinimumLevel.Verbose()
    .WriteTo.File("all.log", outputTemplate: outputTemplate)

    .WriteTo.Logger(lc => lc
        .MinimumLevel.Information()
        .MinimumLevel.Override("Microsoft", Serilog.Events.LogEventLevel.Warning)
        .WriteTo.File("some.log", outputTemplate: outputTemplate))
    .CreateLogger();

var msLogger = Log.Logger.ForContext(Constants.SourceContextPropertyName, "Microsoft.AspNet.Example");
var logger = Log.Logger.ForContext(Constants.SourceContextPropertyName, "MyClass");

msLogger.Verbose("example log; should not go in the minimal file");
msLogger.Information("example log; should not go in the minimal file");
msLogger.Warning("example log");
logger.Verbose("example log; should not go in the minimal file");
logger.Information("example log");

Log.CloseAndFlush();

In the example above, logs of type Information from the Microsoft source context are being written to some.log, when they shouldn’t be because of the .MinimumLevel.Override("Microsoft", Serilog.Events.LogEventLevel.Warning).

[nblumhardt]

Thanks for the follow-up, @augustoproiete .

Unfortunately, MinimumLevel.Override() is not supported at all by sub-loggers. We’ve updated the XDOC for MinimumLevel.Override() to call it out, but it seems we could still do better.

Implementing full support for it would also be great to explore, though I expect it’s going to be very challenging 😃