This happens quite frequently to me. Usually the 2nd try is successful.

This is still happening!

This happened a lot to me the past 2 weeks

@Maarten: my bot is currently mass-importing sitelinks from dewiki.

I think this is an annoying bug and should be resolved in the near future.

Created https://bugzilla.wikimedia.org/show_bug.cgi?id=62126 to make Pywikibot not crash on this.

So this was caused by Inkowik's bot creating new items too fast. It should be slower now and the problem gone away. I am not sure what we can do to prevent it from happening again. We will investigate.

So two users create an item at the same time. Both fire off a transaction. Both get the same id. One gets a new item, the other one an error because the id was already taken?

If you implemnt it like a ethernet collisions, the second one should back off for a random amount of time and than try again.

You probably want to implement some throttling too so a bot can't overload it like this bot did.

Change 139794 had a related patch set uploaded by Xqt:
(bug 66619) Ignore TypeError for bug 46535

https://gerrit.wikimedia.org/r/139794

Can someone please explain if/how the above patch relates to the issue of this bug?

I have not heard anymore complaints about this so I assume this is fine now. Please reopen if it is still problematic.