Cms: Project-Config page in CMS admin times / crashes

[mizziness]

Description

When viewing the project-config section in the CMS (i.e. going to /admin/utilities/project-config), if there are changes to be reviewed in a significantly-large project, the page times out / stops loading / crashes.

This is a fairly annoying/significant issue because anyone who tries to view that page in any of our environments is met with a crashed tab or browser. We essentially can never visit that page.

Steps to reproduce

1. Make changes to the project-config in your project
2. Navigate to the CMS admin dashboard
3. See notice: Your project config YAML files contain pending changes. Review -> and click to go review
4. Page /utilities/project-config begins loading, and does not finish. Buttons don't work, CPU on the server maxes out for a little bit, and eventually I can navigate away or the tab crashes and must be closed/re-opened.

Additional info

• Craft version: 3.5.16
• PHP version: 7.4.3
• Database driver & version: MySQL 8.0.22
• Plugins & versions:
  The list is pretty long, but I did try after removing plugins, and there was no change in behavior so I don't believe plugins directly cause this. We have a significant number of fields in our system, and our DB on average is roughly 500mb. List screenshot below, the crossed out plugins are either custom ones or removed.

[gbowne-quickbase]

I've seen the same behavior. And ./craft project-config/diff also never resolves. If I just press 'Apply Changes Only,' or run a CLI apply, we're golden.

[brandonkelly]

Just resolved this for Craft 3.6 by implementing a custom diffing function, which works with the raw project config data rather than YAML, so it's much faster.

[brandonkelly]

Craft 3.6 RC2 is out now with this change.

[brandonkelly]

Craft 3.6 has now been officially released ✨