branchmap: decode a label only once This moves decoding of a label out of for loop. Minor speed up expected in cases when one branch has multiple heads. For example: someone using bookmarks as branches and hence ending up with multiple heads on default branch. Differential Revision: https://phab.mercurial-scm.org/D5932

branchmap: move __init__ up in branchcache class Making __init__ the first function defined helps understanding the class much better. Differential Revision: https://phab.mercurial-scm.org/D5931

match: delete unused root and cwd arguments from {always,never,exact}() (API) Differential Revision: https://phab.mercurial-scm.org/D5930

match: delete unused root and cwd arguments to constructors (API) Most matchers no longer need the root and cwd arguments. patternmatcher and includematcher still need the root argument for subincludes. Differential Revision: https://phab.mercurial-scm.org/D5929

dirstate: call and cache os.getcwd() in constructor I'm about to make scmutil.matchfiles() not pass the root and cwd paths to match.exact(), since they no longer have any effect. That turned out to have the surprising effect of making some tests (test-rebase-scenario-global.t and test-removeemptydirs.t) crash when the working directory was removed. The problem was that my patch removed the call to repo.getcwd(), which caused the current working directory to not be cached in the dirstate as early as it was before. This patch fixes that by caching the current working directory in the dirstate constructor. Differential Revision: https://phab.mercurial-scm.org/D5928

cleanup: prefer matchmod.{always,never}() over accessing matchers directly We have these factory methods so we should use them. Differential Revision: https://phab.mercurial-scm.org/D5927

match: allow passing in badfn to always() and never() So that no callers are required to access the matchers themselves. Differential Revision: https://phab.mercurial-scm.org/D5926