Sample Code Seems to Incorrectly Add New Identities

[mtaylorfsmb]

Description

I'm working on writing a custom transform and I'm using these docs as an example. While the code for adding a new claim works I believe it erroneously is adding a new ClaimsIdentity every time it is called whether it needs to or not. Given that TransformAsync can be called multiple times then each time this sample code is called it creates a new ClaimsIdentity and adds it to the principal. While it correctly doesn't add the new claim each time it still is creating an "empty" identity each time. So if the method is called 5 times in a single request then it will create 5 new ClaimsIdentity objects to associate with the principal but only the first one will have an actual claim associated with it.

The problems I see with this:

• The Identities collection of the principal is increased each time it is called which means the underlying list(?) might have to increase in size.
• The Identities property will consist of new identities that are empty.
• Each call allocates a ref type that shouldn't be needed.

Page URL

https://learn.microsoft.com/en-us/aspnet/core/security/authentication/claims?view=aspnetcore-6.0#extend-or-add-custom-claims-using-iclaimstransformation

Content source URL

https://github.com/dotnet/AspNetCore.Docs/blob/main/aspnetcore/security/authentication/claims.md

Document ID

b01e1351-d362-fd61-4dcb-bacb21559f76

Article author

@damienbod

[Rick-Anderson]

@blowdart please review or add a reviewer

[blowdart]

@mkArtakMSFT can you assign someone to take a look?