rebuildmeta: optimize by removing quadratic time usage Calling ctx.children() for revision R visits all revisions greater than R. If I remember my algorithmics right, that's O(n^2). Performing an extra traversal, however, is O(n). A quick benchmark on a repository ~20k revisions: before: 445.27s user 1.10s system after: 7.25s user 0.25s system The resulting `svn' directories are exactly the same, and the tests continue to pass.