registrar: introduce new class for registration to replace funcregistrar _funcregistrarbase differs from funcregistrar in points below: - every code paths should use same class derived from _funcregistrarbase to register functions in a same category funcregistrar expects (3rd party) extensions to use (a class derived from) delayregistrar. - actual extra setup should be executed in another function For example, marking revset predicate as "safe" is executed in a class derived from _funcregistrarbase, but putting name of "safe" predicate into safesymbols is executed in another function for it. funcregistrar expects derived classes to do so. New class is named as module private one, because code paths, which register functions, should use not it directly but one derived from it.

dispatch: make loading extra information from extension extensible This patch makes loading extra information from extension module at dispatching extensible. Factoring 'loadcmdtable()' into commands.py is a part of generalization of loading extra information. This extensibility assumes registration of new function like below, for example: - revset predicate - fileset predicate - template keyword - template filter - template function - internal merge tool - web command This patch requires not loader function itself but container module and the name of it, because listing loader function directly up implies actual loading module of it, even if it isn't used at runtime (for example, extensions don't always define revset predicate)

obsolete: fix n^2 marker computation behavior Previously, if you ran obsolete.createmarkers with a bunch of markers that did not have successors (like when you do a prune), it encountered a n^2 computation behavior because the loop would read the changelog (to get ctx.parents()), then add a marker, in a loop. Adding a marker invalidated the computehidden cache, and reading the changelog recomputed it. This resulted in pruning 150 commits taking 150+ seconds in a large repo. The fix is to break the reading part of the loop to be separate from the writing part.

bdiff: (pure) support array.array arrays (issue5130)

mq: restrict generated patch name to 75 characters (issue5117) Super long first line in description lead to very long file name that windows is unhappy about. We restrict the name to 75 char to avoid the issue. 75 seems fine and leave some extra room for '__#' suffix in case of conflict. I does not seems worthwhile to add a dedicated config option to configure the length. It can be done in the future if there is an actual user demand for it.

files: don't recurse into subrepos without a path or -S (issue5127) The 'm.always()' check was needed for when a path to 'sub1' is given, and 'sub1' contains a subrepo itself. But that also caused the automatic recursion when no path was given. Instead, force -S when printing a subrepo if the subpath is an exact match (which will unconditionally recurse once in the nested subrepo).

parsers: optimize filtered headrevs logic The old native head revs logic would iterate over every node, starting from 0, and check if every node was filtered (by testing it against the filteredrevs python set). On large repos with hundreds of thousands of commits, this could take 150ms. This new logic iterates over the nodes in reverse order, and skips the filtered check if we've seen an unfiltered child of the node. This saves approximately a bagillion filteredrevs set checks, which shaves the time down from 150ms to 20ms during every branch cache write.

destutil: choose non-closed branch head at first (BC) Before this patch, destupdate() returns the tipmost (descendant) branch head regardless of closed or not. But updating to closed branch head isn't reasonable for ordinary workflow, because: - "hg heads" doesn't show closed heads (= updated parent itself) by default - subsequent committing on it re-opens closed branch even if inactivation of closed head is needed, update destination isn't it, because it should be merged into to another branch in such case. This patch chooses non-closed descendant branch head as default update destination at first. If all descendant branch heads are closed, destupdate() returns the tipmost closed branch head. For simplicity, this patch chooses adding _destupdatebranchfallback() instead largely changing _destupdatebranch(). This patch changes not only normal lookup code path, but also the "no default branch" code path, for consistency.

formatter: make labels work with templated output To describe the bug this fix is addressing, one can do ``$ hg status -T "{label('red', path)}\n" --color=debug`` and observe that the label is not applied before my fix and applied with it.

hghave: improve description of Hypothesis