That might have worked in your specific situation, but for bigger changesets, you’re almost certainly guaranteed to run into weird conflicts etc with this method, especially if there were many changes to trunk while you were developing in the meantime.

As the SVN manual states, the recommended process is this:

* regularly keep your branch in sync with trunk (or whatever location you branched from) by doing *svn merge -r 1234:1345*, where _1345_ is _HEAD_, and _1234_ is the revision of the commit you made last time you merged (note that _1234_ itself will not be merged from trunk)
* once you’re ready to merge, get branch in sync with trunk one last time, and note the current revision number (lets say that is _1456_)
– switch to a clean copy of trunk, and run *svn merge https://…/trunk@1456 https://…/branches/blah@1456* (do not use _HEAD_ – you’re in for bad surprises if someone else modified one of the files in the meantime)

This will apply the differences between trunk and branch blah at the given revision, which is exactly what you want to merge back. As I said above, the other method may cause trouble; I’ve been there before – you might even lose changes from the branch in the process.