Allow null on UserOptions.AllowedUserNameCharacters

[justindbaur]

Allow null on UserOptions.AllowedUserNameCharacters

• You've read the Contributor Guide and Code of Conduct.
• You've included unit or integration tests for your change, where applicable.
• You've included inline docs for your change, where applicable.
• There's an open issue for the PR that you are making. If you'd like to propose a new feature or change, please open an issue to discuss the change or find an existing issue.

Allow null on UserOptions.AllowedUserNameCharacters to denote that all characters are allowed in a user name.

Description

There are already tests validating that when null is set to this option that non-alphanumeric characters are allowed in user names. This just makes it clear from the type system that null is allowed here and has a meaning.

aspnetcore/src/Identity/test/Identity.Test/UserValidatorTest.cs

Line 77 in b50ab86

manager.Options.User.AllowedUserNameCharacters = null;

Fixes #64078

[dotnet-policy-service]

Thanks for your PR, @justindbaur. Someone from the team will get assigned to your PR shortly and we'll get it reviewed.

[Copilot]

Pull request overview

This PR updates ASP.NET Core Identity’s UserOptions.AllowedUserNameCharacters to explicitly allow null (via nullable reference types) to represent “no character restrictions,” aligning the API contract with existing runtime behavior.

Changes:

• Update UserOptions.AllowedUserNameCharacters from string to string?.
• Add XML documentation clarifying the meaning of null for the option.

[Copilot]

Pull request overview

Copilot reviewed 3 out of 3 changed files in this pull request and generated 2 comments.

[halter73]

Thanks for doing this! I think the correct syntax for modifying the nullability of an existing member is this:

Suggested change

	Microsoft.AspNetCore.Identity.UserOptions.AllowedUserNameCharacters.get -> string?
	*REMOVED*Microsoft.AspNetCore.Identity.UserOptions.AllowedUserNameCharacters.get -> string!
	Microsoft.AspNetCore.Identity.UserOptions.AllowedUserNameCharacters.get -> string?

Then you can undo the changes is PublicAPI.Shipped.txt.