Why records with property named Id needs to be partial?

[takla21]

When we try to build an uno project on any platforms with a record like this

public record Entity
{
    public string Id { get; init; }
}

it fails with this error

error KE0001: The record 'Entity' is eligible to IKeyEquatable generation (due to 'Id') but is not partial. Either make it partial (recommended), either disable implicit IKeyEquality generation using [ImplicitKeys(IsEnabled = false)] on the record itself or on the whole assembly (not recommended).

Here are the list of uno packages we reference on our project

<PackageReference Include="Uno.Core.Extensions.Logging.Singleton" Version="4.0.1" />
<PackageReference Include="Uno.Microsoft.Xaml.Behaviors.Interactivity.WinUI" Version="2.3.1-uno.2" />
<PackageReference Include="Uno.Microsoft.Xaml.Behaviors.WinUI.Managed" Version="2.3.1-uno.2" />
<PackageReference Include="Uno.Material.WinUI" Version="2.4.1" />
<PackageReference Include="Uno.Toolkit.WinUI" Version="2.4.2" />
<PackageReference Include="Uno.Toolkit.WinUI.Material" Version="2.4.2" />
<PackageReference Include="Uno.SourceGenerationTasks" Version="4.2.0" />
<PackageReference Include="Uno.Injectable" Version="2.0.0-dev.10" />
<PackageReference Include="Uno.CodeGen" Version="2.0.0-dev.10" />

[jeromelaban]

@carldebilly may know

[jeanplevesque]

It's apparently an analyzer that isn't shipped...
https://github.com/unoplatform/uno.extensions/blob/c439932faabf3f3287c5f307e9c01601034b0b6a/src/Uno.Extensions.Core.Generators/AnalyzerReleases.Unshipped.md

[dr1rrb]

This is for the IKeyEquality generation https://github.com/unoplatform/uno.extensions/blob/main/doc/Overview/KeyEquality/concept.md

As records have their equality generated, we are also generating a "light" version which only compares the ID (that's why it has to be partial). The main goal of this is to properly track changes in a collection when you update an immutable record in an immutable list (e.g. items = items.Replace(items[0], items[0] with {Title = "New title"})). When comparing only the keys we are able to determine that items[0] is just a an updated version of the same entity, so we will raise a "replace" instead of a "remove" + "add" (and ListView is able to properly animate that change).

This is natively used by feeds, but if you are not interested by this, you can disable it : https://github.com/unoplatform/uno.extensions/blob/main/doc/Overview/KeyEquality/concept.md#how-to-disable-generation

[dr1rrb]

Maybe a transitive reference, but none from the PackageReference you have put in the initial message. You must have some other references somewhere (like in the Directory.props file?). You will have a more complete view in VS's SolutionExplorer under the Dependencies node:

[jeanplevesque]

Where is the ImplicitKeyEquality attribute mentioned in the documentation?

[jeanplevesque]

So the attribute ImplicitKeyEquality mentioned in the documentation doesn't actually exist.
The real one is called ImplicitKeysAttribute.

[dr1rrb]

unoplatform/uno.extensions#1317

[jeanplevesque]

unoplatform/uno.extensions#1317

That PR doesn't solve the documentation issue because the updated name is still not the right one.