Last modified: 2014-03-14 18:09:33 UTC
I was trying to edit some pages on tests wiki https://test.wikipedia.org/w/index.php?title=User_talk:Petrb&action=history I made edit at 17:41, 14 March 2014 Petrb (talk | contribs | block) then I made edit again with &basetimestamp=2013-12-21T09%3A09%3A45Z and THIS EDIT DID PASS, even if the basetimestamp is several months old. How is it possible? Isn't this supposed to display some error? If not, how this parameter is supposed to work? Documentation say that.
The basetimestamp is used to detect edit conflicts. When the conflict is detected and can be resolved automatically than it is done, the same as editing with the gui. Providing no basetimestamp will override all previous edits and will not merge they.
No, basetimestamp is not broken. Your edit conflict was automatically merged. You may want to look at the logic in EditPage.php near lines 1646-1671 to see just how it works (the value from basetimestamp is in $this->edittime). BTW, it would be helpful in the future if you detail the exact API queries you made, rather than just saying "I made edits".