Obsolete attribute is ignored for Blazor component parameters

[stsrki]

I'm changing some of the APIs in my Blazor component library and I'm trying to add an Obsolete attribute to some of the component parameters. The expected behavior was to have an error if the marked parameter was used but the build output shows no error or warning whatsoever.

Example of marked parameter:

[Obsolete( "The Color parameter will be removed. Please use TextColor instead!", true )]
[Parameter]
public TextColor Color
{
    get => TextColor;
    set => TextColor = value;
}

Usage:

<Paragraph Color="TextColor.Black50">
    Some text.
</Paragraph>

[SteveSandersonMS]

This is not something I would expect to work currently since the code generated for a parameter usage doesn't reference the C# property directly (it looks like builder.AddAttribute(x, "YourParameterName", someValue)). We'd have to implement a new feature to make this do something.

Nonetheless I agree this is a valid enhancement request!

Thanks for contacting us.

We're moving this issue to the Next sprint planning milestone for future evaluation / consideration. We would like to keep this around to collect more feedback, which can help us with prioritizing this work. We will re-evaluate this issue, during our next planning meeting(s).
If we later determine, that the issue has no community involvement, or it's very rare and low-impact issue, we will close it - so that the team can focus on more important and high impact issues.
To learn more about what to expect next and how this issue will be handled you can read more about our triage process here.

We've moved this issue to the Backlog milestone. This means that it is not going to be worked on for the coming release. We will reassess the backlog following the current release and consider this item at that time. To learn more about our issue management process and to have better expectation regarding different types of issues you can read our Triage Process.

[Eilon]

We could consider having code-gen use nameof(global::Foo.Bar.ObsoletePropertyName) so that you get the automatic compiler warnings about it:

[stsrki]

Any chance of this getting into the .Net 6 release?

[SteveSandersonMS]

No, sorry. We're only stabilising and fixing bugs now.