discovery: replace "heads" by "changesets" in a output note (BC) When using `hg push --rev X`, the subset considered by discovery is only `::X`. In addition, `X` can be any local revisions not just local heads. As a result the message "all local heads known locally" can be misleading. We replace it with the more accurate "all local changesets known remotely". The message appears when in verbose not, so this is stricly speaking a BC breakage. I am not sure this would be a real issue in practice...

py3: drop incorrect fsencode(findexe(...)) in procutil I recently added the bad call, thinking that findexe() was a standard library function returning a string result, but it's actually our own function returning bytes. Thanks to Yuya for noticing. Differential Revision: https://phab.mercurial-scm.org/D6826

flagprocessors: small code update to clarify parameters 'raw' is really a third mode, not a small variant. Differential Revision: https://phab.mercurial-scm.org/D6807

flagprocessors: deprecate _processflags People should use the specialized version instead now. Differential Revision: https://phab.mercurial-scm.org/D6806

simplestorerepo: stop using `_processflags` directly We now use the specialized versions. Differential Revision: https://phab.mercurial-scm.org/D6805

revlog: stop using `_processflags` directly We now use the specialized versions. Differential Revision: https://phab.mercurial-scm.org/D6804

flagprocessors: use _processflagsraw in easy cases When there are no ambiguity regarding the `raw` value, we can simply use the new method. Differential Revision: https://phab.mercurial-scm.org/D6803

flagprocessors: use _processflagsread in simple cases When there are no ambiguity regarding the `raw` value, we can simply use the new method. Differential Revision: https://phab.mercurial-scm.org/D6802

flagprocessors: use _processflagswrite for write operation There are no ambiguity for 'write' operation so it is simple to replace. Differential Revision: https://phab.mercurial-scm.org/D6801

flagprocessors: introduce specialized functions This make the call site clearer and the open the way to more diverse return types. For now, the same old code is still in use under the hood. Differential Revision: https://phab.mercurial-scm.org/D6800

flagutil: use it in simplestorerepo This remove the other code duplication of the `_processflags` code. To be honest, this code looks very dead since it is not run by either developer nor buildbot. However, we update the code to make the task of reviving this less daunting. Differential Revision: https://phab.mercurial-scm.org/D6799

flagutil: make the error class used by the mixin configurable One of the code duplication use a different error class. So let's make it possible to do so. Differential Revision: https://phab.mercurial-scm.org/D6798

flagutil: use the new mixin use in remotefilelog This remove one of the code duplication. Hooray \o/. Differential Revision: https://phab.mercurial-scm.org/D6797

flagutil: introduce a flagprocessorsmixin class To avoid code duplication, we will provide a simple "ready to use" mixin that carry the appropriate logic. First we use it in standard revlog, we'll remove code duplication in later changesets. Differential Revision: https://phab.mercurial-scm.org/D6796

check-code: allow command substitution with $(command) Both `command` and $(command) are specified by POSIX. The latter nests better. I don't see why we shouldn't allow both (or only the latter). Differential Revision: https://phab.mercurial-scm.org/D6789

run-tests: rename `lcmd` variable to `line_cmd` This is clearer and more in line with some other variable names. (This is a gratuitous cleanup that I made while investigating a bug).

run-tests: rename `lout` variable to `out_line` This is clearer and more in line with some other variable names. (This is a gratuitous cleanup that I made while investigating a bug).

run-tests: clarify "l" variable as "out_rawline" More explicit variable name never hurt. (This is a gratuitous cleanup that I made while investigating a bug).

run-tests: use symbolic constant instead of arbitrary number line matching (This is a gratuitous cleanup that I made while investigating a bug).

rustfilepatterns: shorter code for concatenating slices Differential Revision: https://phab.mercurial-scm.org/D6765

match: simplify the regexps created for glob patterns For legibility of the resulting regexes, although it may help with performance as well. Differential Revision: https://phab.mercurial-scm.org/D6764

rustfilepatterns: refactor the pattern of removing a prefix from a &[u8] Differential Revision: https://phab.mercurial-scm.org/D6766

tests: show the pattern generated for a relative glob Differential Revision: https://phab.mercurial-scm.org/D6763

copies: remove existing copy info from the changeset on amend (BC) When amending a changeset with copy information in the changeset and the new changeset doesn't have any copy information (or similar for "filesadded" and "filesremoved"), we shouldn't keep it. A drawback of this is that we now unconditionally remove these four entries from the extras, breaking any extensions that happened to write entries with the same names (which seems very unlikely). I think I'd heard that there was list of blacklisted keys that would be removed from the extras when a commit is rewritten, but I couldn't find that. It would make sense to add the keys mentioned above there instead of the custom filtering I've added in this patch. Differential Revision: https://phab.mercurial-scm.org/D6752