Description

In the mediaUpload function (for example, used by the upload buttons in the Cover block), there is a check for the current allowed mime types (from the WordPress end), which is then fed into the uploadMedia function which will trigger an error before attempting to upload the file (e.g. here is the error for mime type not allowed for user).

However, currently in the new Site Editor, we're not loading the allowed mime types as part of the server rendered initial state, which means that the list allowed mime types passed in to uploadMedia is empty (wpAllowedMimeTypes), resulting in the editor attempting to upload the file and then failing at the server end.

This one-line change adds in allowedMimeTypes to the server rendered initial state, using the same approach as is used for the post and page editors (from this line in core).

The result after this change is that if a user uploads a file that isn't allowed (testing with an svg file is a convenient way to do it), then we report the error back to the user immediately (along with the filename), instead of displaying a flicker of the file attempting to be uploaded.

How has this been tested?

Manually in the site editor. Add a cover block and attempt to upload an SVG image as the background image.

For testing, I used this image: https://upload.wikimedia.org/wikipedia/commons/2/20/WordPress_logo.svg

Screenshots

Before	After

Types of changes

Bug fix

Checklist:

• My code is tested. (Manually tested)
• My code follows the WordPress code style.
• My code follows the accessibility standards. N/A
• I've tested my changes with keyboard and screen readers. N/A
• My code has proper inline documentation. N/A
• I've included developer documentation if appropriate. N/A
• I've updated all React Native files affected by any refactorings/renamings in this PR (please manually search all *.native.js files for terms that need renaming or removal). N/A