+ # prep_ud() must have been called already.
+ if (!chdir "work") {
+ # Check in the filesystem because sometimes we run prep_ud
+ # in between multiple calls to unpack_playtree_need_cd_work.
+ confess "$!" unless $!==ENOENT;
+ mkdir "work" or confess "$!";
+ changedir "work";
+ mktree_in_ud_here();
+ }