tests: demonstrate how evolve loses transitive copies when interrupted Let's say `b` has been renamed to `c` in commit A and then renamed to `d` in commit B. We now modify A in a way that will cause a conflict when we evolve B. `hg evolve` will now stop and let the user resolve the conflicts, but it will have lost the copy information in the working copy (should still be c->d).

evolve: use ui.configoverride() instead of ui.backupconfig() ui.configoverride() was added in hg 4.1. util.nullcontextmanager() was added in hg 4.4.

topic: use ui.configoverride() instead of ui.backupconfig() ui.configoverride() was added in hg 4.1. util.nullcontextmanager() was added in hg 4.4.