Can we use align: true?

I thought making it more explicit would be better in case any more alignments are added in the future, but I'm fine with it being either way.

I'd prefer if we were consistent between blocks (I think we're using true elsewhere). Also, if we add a new alignment (or remove one), it will update automatically.

Alright, I'll change it to true, then. 🙂

We are removing align from blockAttributes variable. The deprecations rely on this variable so we need to add the attribute to the existing deprecations relying upon blockAttributes.

The align hook actually adds the align attribute itself, so the deprecations should be unaffected as the resulting attribute set would be identical to the current one with align manually defined:

https://github.com/WordPress/gutenberg/blob/master/packages/editor/src/hooks/align.js#L85

Actually, I think I'll go test it at some point later today/tomorrow just to make sure it isn't actually necessary. If it turns out I was misremembering, I'll update this PR to fix the deprecations. Thanks for pointing this out.

@jorgefilipecosta Alright, I just tested to see if aligned Cover blocks from Gutenberg 4.7.0 are preserved when applying my changes. The Cover blocks are indeed preserved properly, so it looks like this PR is ready to be merged.

Hi @ZebulanStanphill thank you for your tests. Like you said blocks created in 4.7.0 are still valid, we are not causing an invalidation problem.
The problem we are causing with this changes is making very old deprecations with alignments not work correctly (these deprecations are not from 4.7 are from older versions like 2.0).
As a sample problem:
If on master we go to the code editor and paste:

<!-- wp:cover {"align":"center"} -->
<section class="wp-block-cover has-background-dim aligncenter"><h2></h2></section>
<!-- /wp:cover -->

The code gets migrated to:

<!-- wp:cover {"align":"center"} -->
<div class="wp-block-cover has-background-dim aligncenter"></div>
<!-- /wp:cover -->

Which is correct, we have an empty cover image block with center alignment.

On this branch, if we paste the same sample the code gets migrated to:

<!-- wp:cover {"className":"aligncenter"} -->
<div class="wp-block-cover has-background-dim aligncenter"></div>
<!-- /wp:cover -->

Which is not correct the aligment was not recognized and the block was treated as a block with a custom className.

Thanks for pointing that out. I have updated the PR to fix this problem. 🙂