Clear member cache by older user name when member user name is updated (16)

[AndyButland]

Prerequisites

• I have added steps to test this contribution in the description below

Resolves #19618 for Umbraco 16

Description

This is a port of #19672 for Umbraco 16. It needed a bit more work than just a cherry-pick, as we no longer have the AdditionalData available on entities that could be used to attach extra information via the entities and use it in the cache refreshers.

Rather it looks like this has been removed and state is now passed only via notifications.

The problem was that with the inheritance structure we had set up for distributed cache notifications, this wasn't made available at the point where we needed to act on it. So I've had to add an additional parameter to the base distributed cache notification handler abstract class, obsolete the old one and provide it in all the handler implementations. But having done that we can pass the details of the member's previous user name to the MemberCacheRefresher and act on it as we did in 13.

Testing

With code like the following, retrieve a member by the user name:

@inject IMemberService MemberService;
@{
    var fred = MemberService.GetByUsername("fred@test.com");
    @if (fred is null)
    {
        <div>Fred not found</div>
    }
    else
    {
        <div>Found Fred: @fred.Email</div>
    }
}

Update the member's user name in the backoffice. Before the PR you will see the member is still found, but after these changes are applied, it should not be.

[Copilot]

Pull Request Overview

This PR backports the member-username cache invalidation enhancements to Umbraco 16, ensuring that when a member’s username changes, both the new and old usernames are used to clear the distributed cache. It also adds state-aware overloads to all distributed cache notification handlers and obsoletes the previous single-parameter overloads.

• Capture and publish the previous username in MemberSavedNotification state.
• Extend MemberCacheRefresher and DistributedCacheExtensions to clear caches by both new and previous usernames.
• Update DistributedCacheNotificationHandlerBase and all implementing handlers to support a state parameter and mark the old overloads obsolete.

Reviewed Changes

Copilot reviewed 33 out of 33 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
src/Umbraco.Core/Services/MemberService.cs	Capture previous username and add it to the save notification state.
src/Umbraco.Core/Notifications/MemberSavedNotification.cs	Introduce PreviousUserNameStateKey constant.
src/Umbraco.Core/Cache/Refreshers/Implement/MemberCacheRefresher.cs	Clear cache entries for both new and previous usernames.
src/Umbraco.Core/Cache/DistributedCacheExtensions.cs	New state-aware overloads and GetPayloads logic.
src/Umbraco.Core/Cache/NotificationHandlers/DistributedCacheNotificationHandlerBase.cs	Add state overload, loop multi‐notification support, obsolete old methods.
src/Umbraco.Core/Cache/NotificationHandlers/Implement/DataTypeSavedDistributedCacheNotificationHandler.cs	Changed saved-handler to remove data-type cache first.

Comments suppressed due to low confidence (2)

tests/Umbraco.Tests.UnitTests/Umbraco.Core/Cache/DistributedCacheExtensionsTests.cs:38

• The tests verify the payloads when removed is false, but there’s no coverage for the removal case (removed = true). Adding a test for GetPayloads(..., true) would ensure the Removed flag and PreviousUsername logic are exercised for deletion scenarios.

        var payloads = DistributedCacheExtensions.GetPayloads(members, state, false);

src/Umbraco.Core/Notifications/MemberSavedNotification.cs:16

• [nitpick] The constant name includes UserName but the value string is PreviousUsername. Consider aligning the casing or wording (e.g., PreviousUserName) in the string to match the constant name for clarity.

    internal const string PreviousUserNameStateKey = "PreviousUsername";

[Zeegaan]

Looks good, tests good 🚀