Classic block missing content in Preview

[joyously]

The content is visible in the editor, but the Preview is missing some content.

To reproduce

1. I was using the Theme Unit Test data from https://github.com/WPTRT/theme-unit-test/
2. Click to edit the Post titled "Markup: HTML Tags and Formatting"
3. Scroll down to see that the Table follows the Block Quote.
4. Click on Preview.
5. See that there is no Table heading following the Block Quote and the formatting of the rest of the page is for blockquote.

Expected behavior
The preview should match the content in the editor.

Screenshots
This is how it looks in the editor:

And this is how the preview looks:

Desktop

• OS: Ubuntu Studio 16.04
• Browser: Firefox 66.0.2
• WP Version 5.1.1
• no plugins, Twenty Nineteen theme

[youknowriad]

I confirm I reproduce the issue, it might be good to open a trac ticket as well as it seems that this happens on the backend in one of the the_content filters.

[joyously]

I created https://core.trac.wordpress.org/ticket/46861

[jorgefilipecosta]

Thank you @joyously for creating this issue and the trac ticket, given that we already have a trac ticket following the normal process and that passed from awaiting review to the milestone 5.3, I guess we can now close this issue and use the trac ticket to follow the progress of this problem.

[SergeyBiryukov]

I was able to reproduce the issue with the following example:

<a href="#" title="&lt;cite&gt; represents a reference to a creative work.">...</a>

It results in this output on the front end:

<a href="#" title="<cite> represents a reference to a creative work.&#8221;>&#8230;</a>

Note the closing quote converted to ”, breaking any markup that follows.

With the wptexturize() filter disabled, the input works as expected.

Using the Classic Editor (in both Visual and Text mode), the output is correct even with wptexturize() enabled:

<a title="&lt;cite&gt; represents a reference to a creative work." href="#">&#8230;</a>

So this appears to be a wptexturize() issue that only manifests with the Block Editor. I think the difference is that the Block Editor does not preserve the escaped <cite> tag in the title attribute, converting it to <cite>, and wptexturize() is confused by that.

I guess the Block Editor should preserve < and > entities in HTML attributes. Reopening the issue, as it seems this should be fixed in Gutenberg rather than in the back end.

[paaljoachim]

Hi @joyously
Is this issue still valid? If so how should we move forward?

@carolinan @glendaviesnz @talldan

[joyously]

Yes, it is still an issue. See Sergey's comment for details.

[carolinan]

I wonder if this should be closed in favor of #15636 which seems to be root cause?

[joyously]

Both issues state the root cause and this one has a lower number...
The other issue is blaming wptexturize, when this issue specifically says that it is not.