Deprecate w-preserve-attrs

[patrick-steele-idem]

w-preserve-attrs → <input style:no-update=”” title:no-update>

Old:

<div style="color:#09c" w-preserve-attrs="style">
    ...
</div>

New:

<div style:no-update="color:#09c">
    ...
</div>

[austinkelleher]

I can take this one.

/cc @mlrawlings

[austinkelleher]

This would be an unlikely case, but do you think we should consolidate w-preserve-attrs and :no-update if both are present? We will of course log a deprecation warning when w-preserve-attrs is used regardless.

<div style:no-update="color:#09c" class="test" w-preserve-attrs="class">
...
</div>

<!-- Doesn't matter that it's listed under `class:no-update` and `w-preserve-attrs`. -->
<div style:no-update="color:#09c" class:no-update="test" w-preserve-attrs="class">
...
</div>

/cc @mlrawlings What do you think?

[austinkelleher]

I'm personally leaning toward consolidating because they will function the same anyway.

[mlrawlings]

@austinkelleher I think consolidation makes the most sense as well. Ideally, this would be done in such a way that the code for w-preserve-attrs can easily be removed in the future.

My thinking is both

<div style:no-update="color:#09c" class="test" w-preserve-attrs="class">
...
</div>

and

<!-- Doesn't matter that it's listed under `class:no-update` and `w-preserve-attrs`. -->
<div style:no-update="color:#09c" class:no-update="test" w-preserve-attrs="class">
...
</div>

Would be transformed to:

<div style:no-update="color:#09c" class:no-update="test">
...
</div>

And then the code for no-update would take over.

[mlrawlings]

FYI, I've added a new method to do deprecations from the compiler that tracks the node and line:column in the original template code.

context.deprecate('deprecation warning text');