Subversion fetch_changesets does not handle moved (root-)directories
I had a standard layout (trunk/branches/tags). I created a new directory called A and moved trunk/branches/tags into A. Then I deleted my SCM in the project and created a new one pointing to A.
This caused all my activity to disappear since the only changesets fetched was the creation of directory A and the move of trunk/branches/tags into A. All other changesets are lost.