<img/> tags missing attribute filter

[jsmoriss]

The HTML tags added to blocks are missing an attribute filter. The 'wp_get_attachment_image_attributes' filter should be applied to the image attributes for compatibility with WordPress.

[antpb]

From the media meeting yesterday @joemcgill mentioned "Gutenberg uses a different markup structure entirely with a different filtering process. I think we would be better off writing upgrade notes that explains how to do this correctly going forward, but am open to solutions that allow back-compat of the previous filter if we can come up with an approach."

I think with that, we can shift our focus on providing an upgrade path for folks that depend on the filter. What should they do now if we choose to not respect the filter?

[joemcgill]

Following up after we discussed this again in the Core Media meeting yesterday and after doing a bit more research this morning. Traditionally, image markup in the editor was composed server side, via get_image_send_to_editor() which uses get_image_tag() under the hood. Neither of these functions apply the wp_get_attachment_image_attributes filter, so this issue really isn't valid as described. The wp_get_attachment_image_attributes filter only applies to image markup that is dynamically generated on the front end, e.g., featured images, gallery shortcodes (see #1451), etc.

That said, supporting backward compatibility for filters like image_send_to_editor, get_image_tag_class, and get_image_tag, which previously did provide a way for themes and plugins to modify the markup of images in the editor, would be a good goal for this ticket.

[danielbachhuber]

That said, supporting backward compatibility for filters like image_send_to_editor, get_image_tag_class, and get_image_tag, which previously did provide a way for themes and plugins to modify the markup of images in the editor, would be a good goal for this ticket.

For image_send_to_editor, see #8472

However, this is also impacted by #10204

[joemcgill]

Ah, thanks @danielbachhuber, I'd missed that ticket. Since that already exists, I'm going to close this one and move the other to (leave it in) the 5.0 milestone for review.