It would have been easier to trace the authorship of changes made before r72349 if you hadn't done that.
I'm sort of unsure what you mean. Just because it's deleted doesn't actually make the revision history die too.. For example, you can easily view the first revision of ResourceLoader.php at http://svn.wikimedia.org/viewvc/mediawiki/trunk/phase3/includes/ResourceLoader.php?revision=68372&view=markup&pathrev=72349
Afaik, you know SVN very well, I must be missing something here.
Sure, it's still all there, it's just harder to access, because you have to muck around with path revisions to find the original files. So to trace, say, the changes to OutputPage.php introduced in the branch merge, instead of:
svn annotate branches/resourceloader/phase3/includes/OutputPage.php
one is obliged to work out exactly when that path was deleted, and then to check out a copy of the branch at the preceding path revision:
svn up -r 72999 branches/resourceloader svn annotate branches/resourceloader/phase3/includes/OutputPage.php
Or alternatively to use a remote path:
svn annotate svn+ssh://svn.wikimedia.org/svnroot/mediawiki/branches/resourceloader/phase3/includes/OutputPage.php@72999
since annotating a path revision on a deleted working copy path does not work:
tstarling@shimmer:~/src/mediawiki/branches$ svn annotate resourceloader/phase3/includes/OutputPage.php@72999 svn: 'resourceloader/phase3/includes' is not a working copy
It's an unnecessary nuisance: we have lots of branches that are out of sync, it's not a problem to leave them there.
Do we intend to leave all of them there for all of time?