AuthenticationOptions.AddScheme() should declare displayName as nullable

[kevinchalet]

The display name is an optional thing and is typically not set for handlers that are not meant to be publicly listed. As such, the AuthenticationOptions.AddScheme() method should declare the displayName parameter as nullable (string -> string?).

aspnetcore/src/Http/Authentication.Abstractions/src/AuthenticationOptions.cs

Lines 52 to 63 in 1268b6e

	/// <summary>
	/// Adds an <see cref="AuthenticationScheme"/>.
	/// </summary>
	/// <typeparam name="THandler">The <see cref="IAuthenticationHandler"/> responsible for the scheme.</typeparam>
	/// <param name="name">The name of the scheme being added.</param>
	/// <param name="displayName">The display name for the scheme.</param>
	public void AddScheme<[DynamicallyAccessedMembers(DynamicallyAccessedMemberTypes.PublicConstructors)]THandler>(string name, string displayName) where THandler : IAuthenticationHandler
	=> AddScheme(name, b =>
	{
	b.DisplayName = displayName;
	b.HandlerType = typeof(THandler);
	});

@HaoK @Tratcher

[Tratcher]

@pranavkm

[blowdart]

To be taken into account in #25310

[kevinchalet]

@blowdart is it open to external contributions? Having to use the null-forgiving operator when calling this method is a bit ugly... 😃

[pranavkm]

@kevinchalet feel free to send a PR to the release/5.0 branch.

[HaoK]

@blowdart this API isn't part of identity, the lowest auth apis had nullable done in 5.0, so something like this should probably be fixed in 5.0

[blowdart]

If it doesn’t chain anything else then sure. If it does open a rabbit hole then no.

[kevinchalet]

PR sent: #25480 😄