Support for WordPress 5.0 and the new editor - Gutenberg

[bobbingwide]

Since early 2017 a new editor has been under development. Code named Gutenberg this new editor is being developed as a feature plugin. It is expected to be merged into core for WordPress 5.0.

We need to be aware of Gutenberg and to attempt to be compatible with it.
Actually, it's the other way round. Gutenberg needs to be backward compatible with us.

According to Gutenberg's README.

Posts are backwards compatible, and shortcodes will still work.

That's not the case right now.

This particular issue may act as the central repository of all our known issues associated with Gutenberg. We will need to create issues in each plugin that is affected by the changes associated with WordPress 5.0 and Gutenberg.

Some extension plugins may benefit from providing full support for the new editor. For example oik-fields may implement the Fields meta-box differently.
Others may just need some tweaks.

There will also be cases where Gutenberg appears to break a site.
In this case we'll have to raise issues against Gutenberg and/or WordPress TRACs if Gutenberg gets merged into core before they're fixed.

Area	Problem	Reference
Classic block	Insert shortcode	Shortcode inserted in wrong place WordPress/gutenberg#4855
Shortcode block	Enclosed content shortcode	CR's ignored WordPress/gutenberg#4456
Custom HTML wp:html	Enclosed content shortcode	CR's ignored - also 4456
Classic block HTML	Edited HTML doesn't survive round trip	CR's ignored - 4456 again
Dashboard side menu	Not scrollable	WordPress/gutenberg#4445
Drag and Drop	Does not work within blocks
[bw_wtf]	Hyphens stripped from HTML comments	User error I believe. See below
Demo	Add new crashes	Warning in logs on qw/wordpress To Be Investigated
bw_geshi shortcode	Unexpected <br />s appearing	bobbingwide/oik-css#9
more tag	Confuses conversion from Classic	p start and end tags in wrong place
shortcode block	Why <>'s and not []'s?	Dashicons-editor-code WordPress/dashicons#261
option to mark posts as Classic	Custom field for editor selection by post
admin	sidebar not scrollable	WordPress/gutenberg#4445
post-new.php	Fatal error: Maximum execution time exceeded
post.php?action=edit	Fatal error: Maximum execution time exceeded
Editor	does not appear when HEARTBEAT is false	bobbingwide/oik-clone#24
Editor	Undefined property: WP_Post::$filter	Back level WordPress-SEO v3.1 in qw/hm
Categories & Tags	Custom taxonomies not working	Need show_in_rest = true
Google map virtual field	Google JavaScript not defined

[bobbingwide]

In a couple of environments I noticed messages in the Chrome console.
These were associated with requests to list users, which were constructed as below.

https://qw/hm/index.php?rest_route=/wp/v2/users?context=edit&per_page=100

I discovered this was associated with issue 3215, which occurs when the site is configured with plain permalinks. The problem is due to there being two question marks in the request.

I raised an improvement request that the plugin should detect when the site uses Plain permalinks and produces a warning. See WordPress/gutenberg#4617

I also added a comment to WordPress/gutenberg#3010 (comment)

[bobbingwide]

I believe the problem I saw with hyphens being stripped from HTML comments in the output from [bw_wtf]. But it could have been due to my accidentally hitting the Insert More Tag in the Classic block.
I still need to check what else happens with real HTML comments. Ah. I've found at least one non Gutenberg bug!

[bobbingwide]

For the time being, since Gutenberg does not perform checks on custom taxonomies not being shown in REST until it’s too late, in the development version, I’ve hardcoded show_in_rest = true for custom taxonomy registration. This should be revisited.

[bobbingwide]

Earlier today I detected a problem when editing an oik-shortcode which had Generate the programmed example selected. I tracked the problem down to a problem called the internal API _wp_footer_scripts in dependencies_cache::capture_scripts. The workaround is to not do anything when inside the replace_editor filter. This requires the same fix in oik-libs.