perftemplating: drop usage of buffer The buffer can consume a lot of memory and change various internal behaviors. Writing to dev/null seems more appropriate when it comes to benchmark.

perftemplating: move template formating into its own function The lambda is not practical when time will come to alter the benchmark code.

perftemplating: fix the revisions argument Before this change, the argument passed to log where a string instead of a list of string. This meant only single character rev were supported... We now properly accepts argument of any length. We also make it possible to specify multiple REV arguments in the same go.

py3: make sure util.username() always returns bytes Differential Revision: https://phab.mercurial-scm.org/D3706

py3: add b'' prefix to make the regex bytes # skip-blame because just b'' prefixes Differential Revision: https://phab.mercurial-scm.org/D3705

phases: use "published" in the phase movement message Using "published" seems smoother than "became public" and more in line with the "phase.publishing" configuration.

phase: clarify the message about movement on command changeset The current message is a bit generic. Since we only print it for phase movement on changeset already common before the pull, we add "local" to the message in and attempt to clarify what changeset the phase movement affected.

fuzz: try and generate an interesting mpatch seed from a repo Differential Revision: https://phab.mercurial-scm.org/D3697

fuzz: structured helpers for creating mpatch seed corpus entries Maybe this is better. I'm not sold, honestly. Differential Revision: https://phab.mercurial-scm.org/D3696

fuzz: new fuzzer for the mpatch code Differential Revision: https://phab.mercurial-scm.org/D3695