If you've just upgraded your server to Subversion 1.5 or
later, then there's a significant risk that pre-1.5 Subversion
clients can mess up your automated merge tracking. Why is
this? When a pre-1.5 Subversion client performs svn
merge, it doesn't modify the value of
svn:mergeinfo property at all. So the
subsequent commit, despite being the result of a merge,
doesn't tell the repository about the duplicated
changes—that information is lost. Later on,
when “merge-aware” clients attempt automatic
merging, they're likely to run into all sorts of conflicts
resulting from repeated merges.
If you and your team are relying on the merge-tracking
features of Subversion, then you may want to configure your
repository to prevent older clients from committing changes.
The easy way to do this is by inspecting
the “capabilities” parameter in
start-commit hook script. If the
client reports itself as having
capabilities, the hook script can allow the commit to start.
If the client doesn't report that capability, have the hook
deny the commit. We'll learn more about hook scripts in the
next chapter; see
the section called “Implementing Repository Hooks” and