WordPress is known for its commitment to backwards compatibility. It prides itself on functional consistency between major releases, and makes sure actions and filters continue to work as expected.
Gutenberg is big and huge and a significant change for the better. Contributors are working to make Gutenberg as backwards-compatible as possible. However, the reality is that we’ll likely taste three flavors:
It continues to work as expected. For example, an enter_title_here filter continues to modify the title placeholder text in Gutenberg. Similarly, Post Type Supports is still the API for defining which features a Post Type supports.
It doesn’t work but there’s an equivalent alternative. Some of WordPress’ existing architecture doesn’t translate directly into Gutenberg. For instance, media_buttons is the old paradigm for registering a button to insert something into the post content. In Gutenberg, Blocks are the new paradigm. Blocks are added to the post content via the Inserter.
It doesn’t work at all. We want to avoid this as much as possible, but there will be some elements you can customize in the Classic Editor that you simply can’t change in Gutenberg.
The Gutenberg Migration Guide documents many of these specifics. New contributions are always welcome. Generally, compatibility solutions are organically prioritized against identified need, expected impact, and level of effort/possibility.
Ultimately, WordPress remains committed to the ethos of backwards compatibility, even when undertaking such a transformational change as Gutenberg. An amazing amount of effort is going into ensuring WordPress sites continue to work as expected. It’s important to acknowledge, though, that backwards compatibility is fundamentally more difficult than the past. The reality has a certain degree of nuance.
“Try Gutenberg” is an initiative, currently scheduled for WordPress 4.9.8, to drive more usage of the Gutenberg editor plugin. A while back, I left an offhand comment listing issues I saw as blockers (those that caused data transformation that would be hard to recover from at scale). This comment apparently received more attention than I expected it to, so now we’re partially focused on making sure those blockers are resolved.
And have we been fixing blockers! A non-exhaustive list includes:
Looking for something to do at Contributor Day? We could use your help!
The Gutenberg Migration Guide is a crowdsourcing project to document WordPress Classic Editor customization points and their Gutenberg equivalents (if such exist). media_buttons is the quintessential example; whereas you might’ve used this action previously in the Classic Editor to register a button, it no longer exists in Gutenberg and the block inserter is its direct equivalent.
We want the migration guide to be as comprehensive as it can be. This is defined as:
Identifying as many integration points as we can find. For instance, there are already 14 actions / filters listed. Some are commonly used, while others are not. As long as we have a good example for how the integration point is used, it makes sense to include in the guide.
Whenever possible, documenting how feature parity can be achieved with Gutenberg. Some integration points do already have Gutenberg equivalents. Others don’t yet, and that’s alright.
You can help make the migration guide more comprehensive. If you don’t have any examples of your own to include, here are a couple of places you can start looking:
Everyone can contribute to the migration guide, regardless of skill set. All you need to do is open a new GitHub issue and report the incompatibility you’ve found. Screenshots and GIFs are tremendously helpful. If you know the underlying problem, then please include that too. If all you know is that a given plugin’s feature doesn’t work in Gutenberg, no worries; simply open an issue and we can help track down the cause. Identifying examples of breakage are what we need help with most.
Feel free to join #hosting-community in the WordPress.org Slack if you have any questions, etc. Thanks for your help!
Since I last wrote two weeks ago, we’re making progress! Key achievements for Gutenberg and the REST API include:
Support for who=authors was added to GET wp/v2/users, making it possible to accurately query for authors. WordPress, for better or for worse, defines an author as user_level!=0. See WordPress/gutenberg#6361 for the context on why we can’t add this logic client-side (#42202 for WordPress 4.9.6).
Improved performance for the _fields= query parameter (e.g. GET wp/v2/pages?_fields=id,title) by ensuring WordPress core will only process the fields requested for the response. Notably, this helps us avoid running the_content when we don’t need to be (#43874 for WordPress 4.9.7).
Minor enhancements to reflect existing WordPress behaviors:
The “Merge Proposal: REST API” GitHub milestone represents the distance we still need to close. Slowly, steadily, we’re bridging the gap, but we could use your help. Here are some of the issues we’re still working through:
To ensure all necessary data is available to Gutenberg, we’ve settled upon permitting unbounded per_page=-1 REST API requests for authorized users. This landed for GET wp/v2/users (WordPress/gutenberg#6627), is in-progress for GET wp/v2/(pages|blocks) (WordPress/gutenberg#6657), and needs to be addressed for categories, tags, and custom taxonomies. We also need to patch core with this enhancement (#43998 for WordPress 4.9.7?)
Capabilities can’t be processed directly client-side (WordPress/gutenberg#6361), so we’ve introduced a new targetSchema concept to communicate which actions a user can perform. See it in action with wp:action-sticky (WordPress/gutenberg#6529) and wp:action-assign-author (WordPress/gutenberg#6630). There are a few other actions we will need to work out, and then we’ll need to patch core (no ticket yet).
Adam is putting together an improved autosaves implementation (WordPress/gutenberg#6257) that I literally cannot wait to see complete. I’m sure he could use some help testing in the near future.
media_buttons is only one of the many ways the Classic Editor can be customized. Wouldn’t it be great if there was a database covering all of them?
This is where you come in! Take a look through the Gutenberg Migration Guide. For each action, filter, and so on, we’d like to document real-world examples of how they’ve been used. Then, for each of those real-world examples, identify how the feature might be replicated in Gutenberg.