AMP custom elements are corrupted by force_balance_tags()

[andremacola]

When pasting a vídeo url on Gutenberg. The embed code do not validate with the Amp plugin. I am doing something wrong? I did not made any customization to the default wp block.

[westonruter]

I've seen this issue come up before. It is an issue with force_balanced_tags() in WordPress core: https://wordpress.org/support/topic/how-to-enable-shortcodes-oembed-for-comments-in-amp-pages/#post-11427212

In short, the function is erroneously converting <amp-youtube... into <amp -youtube....

Notice the space being added. The AMP plugin then parses the document and comes across invalid amp tags.

Can you confirm you are applying this function to the_content?

If so, as a quick fix, you can remove the filter. Otherwise, you could adapt the code linked to in the gist linked to in the support forum topic above.

Ultimately, WordPress core needs to fix it's implementation of balanceTags to be aware of custom elements (which contain hyphens).

[andremacola]

Thanks for the reply.

I'm not using this filter. Actually I am not using any filter in the_content but I am using a Multisite environment and I known Wordpress filter some security stuff in the_content when using MU.

[westonruter]

Actually I am not using any filter in the_content but I am using a Multisite environment and I known Wordpress filter some security stuff in the_content when using MU.

@andremacola I checked and it doesn't seem that force_balance_tags() is being added in multisite. The symptom you are reporting sure seems to be the same, however. Can you try to identify which filter on the_content is causing the issue? Is has_filter( 'the_content', 'force_balance_tags' ) returning false on your setup where the_content() is called?

[andremacola]

@westonruter You were right, some other developer did a very old commit using force_balance_tags to remove empty paragraphs. Can close the ticket

[westonruter]

I'm going to leave this open for now to track getting a WordPress core fix for this, since it has come up twice now.

[westonruter]

I filed a core ticket with the fix: https://core.trac.wordpress.org/ticket/47014