DiagnosticSourceEventSource supports base class properties

[noahfalk]

Fixes #41300

Previously DiagnosticSourceEventSource would only iterate and recognize properties that were declared on the most derived type.
Now it can capture properties that were inherited from a base class too.

@dotnet/dotnet-diag - can someone review?

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Issue Details

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Fixes #41300

Previously DiagnosticSourceEventSource would only iterate and recognize properties that were declared on the most derived type.
Now it can capture properties that were inherited from a base class too.

@dotnet/dotnet-diag - can someone review?

Author:	noahfalk
Assignees:	-
Labels:	area-System.Diagnostics.Tracing
Milestone:	-

[davmason]

EventSource also only looks at the derived type's fields and methods. I remember it being an intentional decision, but this was back in 2014ish and I can't remember why it was intentional. There was some scenario it broke to include the base class fields/methods.

[tarekgh]

LGTM

[tarekgh]

There was some scenario it broke to include the base class fields/methods.

I can think if the base and inherited classes define non-virtual same property.

    public class A { public int P1 { get; set; } }
    public class B : A { public new int P1 { get; set; } }

[noahfalk]

Thanks guys! EventSource requires every method to be annotated with [Event] or [NonEvent] so I could easily imagine including new methods would break the init logic for some pre-existing EventSource. I think that will be a fairly different scenario than this one. It is theoretically possible that someone wrote a DiagnosticSourceEventSource listener that will fail if more properties than expected are enumerated, but it seems unlikely:

• The typical pattern is to use anonymous types for DiagnosticListener arguments in which case there are no additional base class properties to enumerate
• ImplicitTransform is intended as a development time scenario when you don't know which properties you need, after which the tool author would switch to an explicit property list
• Anyone who wrote code that breaks in this scenario would probably also break if a library author added a new property to their type. It would be a very version brittle technique with no benefit I am aware of so I am speculating folks wouldn't be doing it.