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.