transaction: explain why some recovery failed Right now we issue a message about failing to recover some file, but not why. It seems useful to add some information about that. (This is an opportunity improvement while looking at something next to that.) Differential Revision: https://phab.mercurial-scm.org/D10842

copyfiles: deal with existing file when hardlinking If the hardlinking fails, we fallback to `shutil.copy`, but do not consider future hardlinking doomed. This is a slight improvement from the current situation, we still avoid hardliking in a case we might be able to do it. However this does not have an impact of the rest of the operation. (This is an opportunity improvement while looking at something next to that.) Differential Revision: https://phab.mercurial-scm.org/D10841

clone: cleanup the "cleanup dir" logic used during local clone With the previous code, there was a small windows were we could delete too much data. This should no longer be the case. (This is an opportunity improvement while looking at something next to that.) Differential Revision: https://phab.mercurial-scm.org/D10840

config: add an experimental option to list all known config That option is not ready for prime-time, hence the `exp-` prefix. However, this is a good base to start going toward completion. This is also quite useful for developer on its own for now. Differential Revision: https://phab.mercurial-scm.org/D10356

revlog: byteify a few error strings Differential Revision: https://phab.mercurial-scm.org/D10875

revlog: fix a typo closing the wrong file Caught by pytype as possibly being None, but the file is closed in the previous conditional. Differential Revision: https://phab.mercurial-scm.org/D10874

py3: byteify the version string passed to the deprecation warning method The other callers were already correct. Differential Revision: https://phab.mercurial-scm.org/D10873