I just ran into the following bug. It appears that the conflict resolver doesn't properly follow branch (copy) history when searching for details.
[[[ $ svn sw ^/subversion/branches/shelve-checkpoint3 [...] $ svn merge ^/subversion/trunk@1802151 --- Merging r1801593 through r1802151 into '.': [...] C tools/dist/templates/nightly-candidates.ezt --- Recording mergeinfo for merge of r1801593 through r1802151 into '.': U . Summary of conflicts: Tree conflicts: 1 Searching tree conflict details for 'tools/dist/templates/nightly-candidates.ezt' in repository: Checking r1801838...svn: warning: apr_err=SVN_ERR_FS_NOT_FOUND svn: warning: W160013: '/repos/asf/!svn/rvr/1802151/subversion/branches/shelve-checkpoint3/tools/dist/templates' path not found /home/julianfoad/src/subversion-c/subversion/svn/merge-cmd.c:553, /home/julianfoad/src/subversion-c/subversion/svn/resolve-cmd.c:157: (apr_err=SVN_ERR_WC_CONFLICT_RESOLVER_FAILURE) svn: E155027: Failure occurred resolving one or more conflicts ]]] The conflict is a delete-delete: the file 'nightly-candidates.ezt' was deleted in branch shelve-checkpoint@r1801823 (note: that's a different branch) and also in trunk@r1801838. That branch was branched to shelve-checkpoint3 in r1802284. The problem is that the look-up of the parent full-path (including branch name) fails because the branch 'shelve-checkpoint3' didn't exist in r1802151. - Julian
