We just moved (c 6months ago) to Subversion, at my instigation. We moved
from VSS6.0a which was awful beyond describing. Some of my colleagues were
worried about the fact that Subversion did not, by default, lock files.
They are not worried now. We have had only two instances of incompatible
updates in 6 months; and we were glad that Subversion found those for us.
If the changes had been made serially under VSS, we would have been in a
mess.
It is worth noting that the VSS6 locking strategy does not prevent
incompatible updates, it just serialises them. This is the very worst
scenario, because incompatible changes are not flagged. Now that we have
persuaded our developers to update frequently (hourly even), we are very
relaxed with Subversion's default strategy.
Having said that, you can get Subversion to lock files. There might be a
justification for this for binary files like, for instance, Word documents,
because Subversion has no way of doing a diff. For text documents, we have
not found a single drawback to a non-locking strategy; and we have found
some advantages. Furthermore, some programs that use binary files, like
some modelling tools, have Subversion add-ons that allow concurrent edits
and deal with the problems of identifying differences themselves - Visual
Paradigm is an example of such a tool.
HTH
Peter
