debugdiscovery: add missing byte string marker to some help text This is causing crash when using --help. Differential Revision: https://phab.mercurial-scm.org/D10227

debugdiscovery: also integrate the discovery output in the json one We add a way for formatter to informs code that free output is unwanted, and we incorporate it in the json output. Differential Revision: https://phab.mercurial-scm.org/D10224

debugdiscovery: add support for Json output They are some pre-output that will be impractical, I'll take care of it in the next changeset. Differential Revision: https://phab.mercurial-scm.org/D10223

perf-helper: add a new sampling revset based on anti-chain See inline documentation for details. Differential Revision: https://phab.mercurial-scm.org/D10222

perf-helper: add a small extension with revsets to select repository subset Playing with discovery requires building interesting case. To do this we need revsets to try to generate them. We start with a quite simple one. See documentation for details. Differential Revision: https://phab.mercurial-scm.org/D10221

amend: mark commit obsolete after moving working copy We were doing it this way: 1. move working copy (repo.setparents) 2. add obsmarkers (scmutil.cleanupnodes) 3. fix dirstate (dirstate.normal/drop) Step 1 and 3 are closely related, so let's move them together. It seems safest to create the obsmarkers last. This patch thus makes the order 1, 3, 2. Differential Revision: https://phab.mercurial-scm.org/D10197

pull: allow to specify multiple sources I end up needing that on a regular basis and it turn out to be very simple to implement. See documentation and test for details. Differential Revision: https://phab.mercurial-scm.org/D10159