Dynamic blocks not working when added after a page break block.

[youknowriad]

Related Gutenberg Ticket ​https://github.com/WordPress/gutenberg/issues/12218

Use this HTML in your post

<!-- wp:heading -->
<h2>Test</h2>
<!-- /wp:heading -->

<!-- wp:nextpage -->
<!--nextpage-->
<!-- /wp:nextpage -->

<!-- wp:quote -->
<blockquote class="wp-block-quote"><p>TEST</p><cite>ETSTTSTT</cite></blockquote>
<!-- /wp:quote -->

<!-- wp:latest-posts /-->

And notice that the latest posts block is not showing up in the second page.

The reason is simple, the string passed to do_blocks is a string starting with <!-- /wp:nextpage --> which means the content is not parsed properly by the gutenberg parser.

[youknowriad]

The patch above is a simple and safe fix for this. A more complex fix could be achieved in the parser itself, but I think we should go with the safest approach for now.

[azaozz]

How about:

$content = ltrim( $content, '<!-- /wp:nextpage -->' );
$content = rtrim( $content, '<!-- wp:nextpage -->' );

to catch cases of "left over" partial block boundaries when there are more than two pages :)

[azaozz]

Also, the trimming will probably be better to run on the 'content_pagination' filter, here: https://core.trac.wordpress.org/browser/branches/5.0/src/wp-includes/class-wp-query.php#L4013.

[pento]

45401.diff​ implements the block marker removal in WP_Query::setup_postdata(), where all of the other nextpage handling happens.

I don't think we need to run it on the content_pagination filter, inline keeps all of the relevant code in one place.

[noisysocks]

45401.diff​ works well in my testing. I tested:

• That the bug as described in the ticket description is fixed
• That multi-page posts work when published
• That multi-page posts work when previewed
• That page breaks at the start of a post are ignored
• That having two page breaks next to each other creates a blank page

[azaozz]

Work well here too. To add to the list by @noisysocks:

• Empty lines left over after removing the block delimiters don't seem to affect anything.

[pento]

In 43940:

Query: Remove nextpage block delimiters when setting up global post data.

WP_Query::setup_postdata() splits the post up by <!--nextpage-->, which causes invalid block data to be contained in the post content.

This change removes the <!-- wp:nextpage --> and <!-- /wp:nextpage -->, as well.

Props pento, youknowriad, azaozz, noisysocks.
See #45401.

[ocean90]

Is there a unit test somewhere to verify that [43940] is working correctly?

[desrosj]

In 44276:

Query: Remove nextpage block delimiters when setting up global post data.

WP_Query::setup_postdata() splits the post up by <!--nextpage-->, which causes invalid block data to be contained in the post content.

This change removes the <!-- wp:nextpage --> and <!-- /wp:nextpage -->, as well.

Props pento, youknowriad, azaozz, noisysocks.

Merges [43940] into trunk.

See #45401.

[SergeyBiryukov]

A new ticket can be created for unit tests. Let's close this one, as the milestone is now completed.