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