S6672 — Generic logger injection should match enclosing type

Why is this an issue?

In most logging frameworks, it’s good practice to set the logger name to match its enclosing type, as enforced by {rule:csharpsquid:S3416}.

Logging frameworks can define or use Generic interfaces for the logger, such as ILogger<TCategoryName>.

The use of a logger of a generic type parameter A (e.g. ILogger<A>) in a type different than A, say B, goes against the convention.

Because the instance of type A would log with a logger named after B, log items would appear as if they were logged by B instead, resulting in confusion and logging misconfiguration:

• overriding defaults for the logger named after A would not take effect for entries logged in the type A
• fine-graned logging configuration would not be possible, since there would be no way to distinguish entries logged in the type A from entries logged in the type B

Further details and examples are provided in {rule:csharpsquid:S3416}.

This rule specifically targets the generic logging interface ILogger<TCategoryName> Interface defined by Microsoft Extensions Logging.

How to fix it

Change the generic type parameter of the ILogger interface to match the enclosing type.

Noncompliant code example

class EnclosingType
{
    public EnclosingType(ILogger<AnotherType> logger) // Noncompliant
    {
        // ...
    }
}

Compliant solution

class EnclosingType
{
    public EnclosingType(ILogger<EnclosingType> logger) // Compliant
    {
        // ...
    }
}

Resources

Documentation

• Microsoft Learn - .NET logging and tracing
• Microsoft Learn - Generic interface
• Microsoft Learn - ILogger<TCategoryName> Interface
• Microsoft Learn - Logging in C# and .NET - Log category