Comment by masklinn

Yep, svn has a lock feature but it is opt-in per file (possibly filetype?)

A pretty good tradeoff, because you can set it on complex structured files (e.g. PSDs and the like) to avoid the ballache of getting a conflict in an unmergeable file but it does not block code edition.

And importantly anyone can steal locks by default. So a colleague forgetting to unlock and going on holidays does not require finding a repo admin.