I'm not sure if the problem here is the large file ( > 600kb), the large diff (45kb), or a combination of the two.
**Steps to replicate the issue**
Before starting: if you wouldn't be happy if this kills your browser, then maybe open a new one first.
* go to [[ https://en.wikipedia.org/wiki/List_of_fake_news_websites | en:List of fake news websites ]]
* click the History tab
* Note:
** raw size is 647kb, way over the standard for en-wiki
** edit rev #1196087966 is +45,361 bytes, a very large edit (made by script)
* Select revs 1196087966 and 1196087209 (at this writing, the top two revisions)
* click the Compare selected revisions button
* Scroll down, try to view the entire diff, and try to access the edit summary and Publish buttons near all the way to the bottomend.
Alternatively: just go here: https://en.wikipedia.org/w/index.php?title=List_of_fake_news_websites&diff=1196087966&oldid=1196087209
**What happens?**:
* Displays one or two screensful of diff wikicode, following that, many, many screens of white space (i.e., a long vertical scroll bar on the right side of the page, with nothing visible as you scroll it). The Edit summary field, the 'Publish' buttons and other end-of-page content are not displayed. Back arrow on the browser is inoperative.
* Eventually, the browser tab or the browser may hang up completely, browser back-arrow is inoperative
* If you wait long enough, eventually it may put up a dialog box pinned to the window top with "Page unresponsive. You can wait for it to become responsive or you can exit the page." ( Wait ) ( Exit the page )
For what it's worth, the same page has a +16.5kb edit at revision 1194194504, and I don't have any problem diffing that one with the previous revision; i.e., this diff:
https://en.wikipedia.org/w/index.php?title=List_of_fake_news_websites&diff=1194194504&oldid=1194057257 so the problem appears to be the size of the edit, not the size of the page.
**What should have happened instead?**:
Display the complete diff page, including the bottom matter allowing inputting of an edit summary, and display 'Publish" and other buttons.
**Other information** (browser name/version, screenshots, etc.):
1. Vivaldi (Chromium based) 6.5.3206.53 64kb
Windows 10 Version 22H2
JS V8 12.0.267.14
16GB RAM, 5.6GB available
2 iPhone 15X 64GB (10.5 free), iOS 15.7
3. Chrome Version 120.0.6099.216 (Official Build) (64-bit)
4. Opera One (version: 106.0.4998.41), Chromium version:120.0.6099.217