This feature works on a diff listing. After replying on a diff listing, can/should it reload the page itself and not just the diff listing? I think I would prefer to see the page, but perhaps others would prefer to continue to see the diff listing so they can make further replies.
Topic on Talk:Talk pages project/Replying/Flow
What is a diff listing ?
A comparison of two versions of a page showing the differences. For example, https://en.wikipedia.org/w/index.php?title=Wikipedia_talk:WikiProject_Disambiguation&oldid=prev&diff=1112103034&diffmode=source
So you mean just a diff. Presumable a diff, with preview mode enabled ? You are making a reply on that page, and then it refreshes the diff, but not the preview ? Or rather I guess, you see the same diff, with the same preview, and not the later revision that you have just created I guess.
Honestly, I wonder if previews of diffs shouldn't even have reply links...
I'm not sure what you mean by "preview mode enabled". If I open a diff listing (commonly by clicking on (xxx changes) on a watchlist entry, I see the changes that were made to the talk page. The reply tool works on this diff listing and I am able to add to the discussion. I see my new comment on the page. So what I am seeing at this point is not really the diff between the versions listed at the top anymore, it is the diff listing I had been looking at with the new comment appended. If I reload the page with the browser reload, the new comment disappears.
It is convenient to be able to reply on a diff listing. but it can lead to confusion also. Sometimes, I do a browser reload to see if there have been responses to my reply, and of course that doesn't work because the url is set to the diff listing, not the "live page".
Perhaps, as you say, "previews of diffs shouldn't even have reply links"
I'm not sure what you mean by "preview mode enabled".
There’s a setting on Special:Preferences#mw-prefsection-rendering-diffs labeled Do not show page content below diffs
. The default is disabled, so most users probably don’t even know about it.
If I reload the page with the browser reload, the new comment disappears. […] Sometimes, I do a browser reload to see if there have been responses to my reply, and of course that doesn't work because the url is set to the diff listing, not the "live page".
It depends on how you open the diff. Most on-wiki diff links contain the revision ID of both the “before” and the “after” revisions, so they indeed don’t contain changes made after the link has been generated. Links in notification emails, however, contain a special diff link that ends with diff=0&oldid=123456 – 123456 is of course a made-up revision ID and is substituted with the actual revision ID of the “before” revision, but 0 is literally a zero, and means “the latest revision at the moment the page is loaded”, so if I press F5, I see my own comment as well as any eventual replies to it. This is probably a workaround for the fact the link is clicked potentially much later than it’s generated (and thus new edits may happen during this time), but it has the side affect that reloads behave differently (which may or may not match the user’s expectations). These are not some black magic, such links could be generated on-wiki as well, for example using gadgets/user scripts. Actually, there’s one on-wiki place where such links are generated (in this case probably for performance reasons): the diff-to-current links on non-diff old revision pages like https://www.mediawiki.org/w/index.php?oldid=123456. (N.B. There are reply links even on this page, although reloading would clearly not work. The links don’t work as these comments have been archived since, but they would if DiscussionTools could find the comments in the latest version.)
Perhaps, as you say, "previews of diffs shouldn't even have reply links"
I’m strongly against removing the links from diffs. As I mentioned above, in some cases there’s no confusion, but even in others having to navigate to another URL to be able to reply makes one of the core values of the reply tool (being able to reply quickly) less true. Maybe there could be a warning within the tool or after posting that informs the user if the issue is really present (i.e. old revisions without diffs and diff views without diff=0).