Nah, I don't think that's right. Versioning may make sense in some scenario
(as my comment implicitly acknowledged), but calling the rule above
"horrible" is denying the fact that it makes perfect sense in a lot of
I called your saying web apps are special and make last in the general rule horrible.
Web apps aren't special, whether first or last edit wins is decided on whether it's acceptable to lose data or not in a given situation regardless of it being a web app or any other kind of app.
Indeed it is the most common way to implement concurrency
handling: doing nothing because last wins is normally fine.
That's not implementing concurrency handling, it's ignoring it.
If user U says the state of a model is S, and user W says a
millisecond later that it is T, and the edition made by W does not
depend on the exact previous state of the model, then why you should
not believe W? He said it is T, so let it be T.
Because you don't know it was a millisecond later, it could have been 10 minutes later because user W sat there looking at the screen forever. User U may have changed many fields on the model while user W just updated one and you've now lost all of the data user U entered effectively rolling back the record.
If that's acceptable, fine, last edit wins, however, for many if not most business type objects, it's not OK.
From the point of view of user U, he doesn't know whether the requests
were interleaved or sequential, and he does not care normally. All he
knows is that after he took a bit of coffee someone else edited the
same record and now it looks different.
Not just different, all of his work was lost because user W updated one unrelated field. User U is now very pissed.