An edit conflict is a computer software problem encountered on wikis. An edit conflict occurs when a shared document is being edited by more than one person at the same time and a conflict is generated. One person attempts to edit the document, but upon trying to save the new version, another person has already modified the document in the intervening time period, thus causing a difference between the attempted edit and the already-made edit that must be resolved manually. The software will then generate an "edit conflict" error message. According to computer writer Gary B. Shelly, "many wikis will block the contributor who is attempting to edit the page from being able to do so until the contributor currently editing the page saves changes or remains idle on the page for an extended period of time."[1]
The problem is common when working on heavily-edited articles on Wikipedia, such as those about a "current event" or a "person suddenly in the news",[2] or on other "high traffic pages".[3]
If a significant amount of new text is involved, the editor who receives an "edit conflict" error message can cut and paste the new text into a word processor or similar program for further editing, or can paste that text directly into a newer version of the target document. Simple copyediting can be done directly on the newer version, and then saved.[2]
For example, edit conflicts can arise when two or more editors are working on Google Sites.[4]
A similar problem can occur when two or more users simultaneously edit the same file in a revision control system that does not have file locking. See Concurrent Versions System.