Gutenberg: Extra P tags added to custom dynamic blocks

[mattheu]

I have a a custom block that is dynamic and rendered using the render callback.
The custom block renders the excerpt.

The render callback returns something like this:

<div>
    <a href="http://example.com"><?php echo get_the_excerpt(); ?></a>
</div>

Prior to Gutenberg 4.6 this worked as expected. After updating, I now get paragraph tags added around the link.

Digging into this a bit - it seems the regression was caused by this change: https://github.com/WordPress/gutenberg/commit/2a66db0fc99a9fb1ba99f61e59e6a0b2a4a5f9ef#diff-6ff32417da0658502e7caa1a1abbeae6

The key difference is the new code restores the wpautop filter at a later priority, which is still getting run.

Digging into this some more - it is actually because get_the_excerpt internally calls apply_filters( 'the_content' - which is a bit of a headache.

To Reproduce
The small test case below will reproduce the issue on the Gutenberg master.

add_action( 'after_setup_theme', function() {
    register_block_type( 'test/autopbug', [
        'render_callback' => 'test_autop_bug_render_callback',
    ] );
} );

function test_autop_bug_render_callback() {
    ob_start();
    ?>
<div class="test-autop-bug">

    <a href="http://example.com"><?php echo get_the_excerpt(); ?></a>

</div>
    <?php return ob_get_clean();
}

Then add the following block to a posts content using the code editor:

<!-- wp:test/autopbug /-->

Then on the front end inspect the markup. The link will be wrapped in a paragraph. If you remove the call to get_the_excerpt then the link is not wrapped in a paragraph.

[danielbachhuber]

Does this issue reproduce with 5.0-RC3 too, or simply the plugin?

[mattheu]

I’ll try and test with 5.0-RC3

[mattheu]

@danielbachhuber Confirmed this is an issue with 5.0-RC3

[danielbachhuber]

@mattheu Ok. Can you create a Core Trac ticket and we'll get this fixed in 5.0.x? Most of the PHP code in Gutenberg is going away once 5.0 ships.

[montaniasystemab]

This is still reproducible with WP version 5.0.3, using get_the_excerpt() inside a server rendered block

[tyrann0us]

Maybe related to #12530? There's a workaraound mentioned in https://github.com/WordPress/gutenberg/issues/12530#issuecomment-443736873.

[websevendev]

Another potential workaround - if you present the HTML as a core/html block and run it through do_blocks() then wpautop doesn't seem to be applied:

function test_autop_bug_render_callback() {
    ob_start();
    ?>
<div class="test-autop-bug">

    <a href="http://example.com"><?php echo get_the_excerpt(); ?></a>

</div>
    <?php return do_blocks('<!-- wp:html -->' . ob_get_clean() . '<!-- /wp:html -->');
}

Not sure if that has any side effects.

[jg314]

I'm also seeing this issue in WordPress 5.1.1, but it does look like there's a ticket open on Trac at https://core.trac.wordpress.org/ticket/45495 to deal with this bug.

[benedict-w]

I see this too - strangely on some sites and not others. On one site it works correctly on staging, but the <p> tags are appearing in custom blocks on the production site :( It also adds <br> in unwanted places e.g. between an image wrapped in an anchor.