I've been thinking about this for a bit, and am I right in thinking that it's the same situation when the user didn't close the first edit window at all? i.e.:

1. Open a random page
2. Make a edit
3. Wait for edit to be saved via EditRecovery
4. Close the page without saving
5. As a different user (or as the same user in a different browser, or just any other user?), open the same page
6. Make a edit
7. Save page
8. Go back to the first edit window, and there's no indication that another edit has been made

That is, until one clicks save, at which point any edit conflict will be caught. It certainly seems like something that Edit Recovery should make more apparent, but I also wonder whether it's actually more widespread and so should be fixed elsewhere.

I think a related Wishlist proposal would probably help: T329975: Notify user when another user tries to edit an article that is being edited at the same time (although if there's to be a notification of other-edits, then that'd mean that when an edit window is re-opened the user would get two notifications, one for Edit Recovery and one about the subsequent edit).

In T351435#9347139, @Samwilson wrote:

I've been thinking about this for a bit, and am I right in thinking that it's the same situation when the user didn't close the first edit window at all? i.e.:

1. Open a random page
2. Make a edit
3. Wait for edit to be saved via EditRecovery
4. Close the page without saving
5. As a different user (or as the same user in a different browser, or just any other user?), open the same page
6. Make a edit
7. Save page
8. Go back to the first edit window, and there's no indication that another edit has been made

That is, until one clicks save, at which point any edit conflict will be caught. It certainly seems like something that Edit Recovery should make more apparent, but I also wonder whether it's actually more widespread and so should be fixed elsewhere.

I think a related Wishlist proposal would probably help: T329975: Notify user when another user tries to edit an article that is being edited at the same time (although if there's to be a notification of other-edits, then that'd mean that when an edit window is re-opened the user would get two notifications, one for Edit Recovery and one about the subsequent edit).

It is definitely part of the overarching issue, but T329975 would not help if the user isn't actively editing (since no storage of earlier edits is assumed) :)

I have personally conflicted with myself a few times while testing patches for PageTriage with a workflow similar to this:

1. I make a edit wait for a bit and then decide to abandon the edit by navigating away and then clicking on the beforeunload dialog
2. Come back and tag the page with a maintainenance notice
3. Open the edit page again, and the EditRecovery dialog pops up and the tags added by PageTriage are removed.

If that last situation is true, then it could at least do a check upon opening the editor to compare base revision and warn the user if they are different.

Don't you think @Samwilson

T329975 would not help if the user isn't actively editing

You mean if the other user wasn't actively editing? That's true.

do a check upon opening the editor to compare base revision and warn the user if they are different.

It definitely could do that. It could look at the value of editRevId when loading and if it is different to the value stored it could add to the notification text and say "Your unsaved changes have been automatically recovered. Note that the page may have changed since you started editing, please 'show changes' before saving."

I think I wasn't quite grokking the scope of T329975, I was thinking that it'd alert the user to any other edit to an article, i.e. that when our user comes back to edit an article and the Edit Recovery data is loaded, there would be another thing that checks whether any other change has happened and would show a separate alert. That would mean that it'd still work even without Edit Recovery in the picture (i.e. if someone was just taking a while in editing, they'd still get notified of a change).