convert: don't drop commits that are empty in the source when using --filemap I ran into this when using `hg lfconvert --to-normal` (which uses the filemap class internally), and saw that commits with nothing but a branch change were dropped. We could put in an option that only lfconvert uses internally. But silently dropping anything other than a commit where all changes were excluded seems unintended. For example, there's a message in mercurial_sink.putcommit() if it drops an empty commit. (And the reason that isn't kicking in here is because lfconvert isn't passing --filemap, so the self.filemapmode conditional there is always False.) The naive change of `return not files` broke test-convert-filemap.t, so this is a little more elaborate than needed for converting from largefiles.

convert: add missing numcommits() override to hg sources Otherwise, the progressbar in converter.walktree() gets None as its total during the initial scan. (Though that seems harmless, and there are other foreign vcs sources without this.)

testrunner: make `-j100 --runs-per-test=100 test-foo.t` use 100 jobs It would use only 1 job since 1039404c5e1d (run-tests: print number of tests and parallel process count, 2018-10-13), but I'm pretty sure that was unintentional. Differential Revision: https://phab.mercurial-scm.org/D5557

narrow: use merge.ACTION_GET instead of duplicating 'g' constant As suggested by Yuya. Differential Revision: https://phab.mercurial-scm.org/D5512

narrow: drop explicit dirstate write The dirstate is written when the wlock is released, so we don't need to write it explicitly in updateworkingcopy(). I don't know why I put it there in the first place (tests pass without it even in the commit that introduced it). Differential Revision: https://phab.mercurial-scm.org/D5515

histedit: fix --continue and --abort when curses is enabled I overlooked this when I did the initial import. Differential Revision: https://phab.mercurial-scm.org/D5540

graft: abort if --date/user specified with --currentdate/currentuser (BC) They are conflicting options. Let's explicitly ban such combination. Note that this means you need "--no-currentdate --date" to override --currentdate specified in aliases/defaults.

amend: turn currentdate into tri-state bool so config option can be negated Otherwise, rewrite.update-timestap couldn't be overridden by --no-currentdate. FWIW, which do we like? --no-currentdate vs --no-current-date. If the latter is preferred, maybe we can add "graft --current-date" and deprecate "--currentdate".

discovery: improve partial discovery documentation The older documentation could be improved.

discovery: add a simple `addinfo` method The method can directly process a sample result. This makes the main code simpler to follow.

discovery: move missing tracking inside the partialdiscovery object This is the final set that we need to track to have a fully up to date information within the object.

discovery: add a `iscomplete` method to the `partialdiscovery` object The method is used by higher level logic to know if the initial discovery question has been answered.

discovery: update undecided from common directly within partialdiscovery The object knows when there are changes in the "common" set, so it is a good place to update the undecided set.

discovery: move undecided set on the partialdiscovery To initialize it, we need to know the discovery target. This commit only move the set on the `partialdiscovery` object, later changeset will take advantage of it.

histedit: use context manager for locks Differential Revision: https://phab.mercurial-scm.org/D5542