Description

When a plugin uses @wordpress/build on a site where Gutenberg is not installed, the pages fail to load with a console error: Uncaught (in promise) TypeError: The specifier “@wordpress/a11y” was a bare specifier, but was not remapped to anything. Relative module specifiers must start with “./”, “../” or “/”.

Step-by-step reproduction instructions

1. Install a plugin that uses wp-build and registers a page (https://github.com/dhasilva/minimal-wp-build-test is a minimal plugin made to test this).
2. Go to its page (Tools → Minimal WP-Build Test with the test plugin above)
3. Check that it loads correctly if Gutenberg is installed, but fails to load if Gutenberg is not activated

Screenshots, screen recording, code snippet

Environment info

"@wordpress/build": "0.7.0"
No Gutenberg installed

Please confirm that you have searched existing issues in the repo.

• Yes

Please confirm that you have tested with all plugins deactivated except Gutenberg.

• Yes

Please confirm which theme type you used for testing.

• Block
• Classic
• Hybrid (e.g. classic with theme.json)
• Not sure