revert: remove dangerous `parents` argument from `cmdutil.revert()` As we found out the hard way (thanks to spectral@ for figuring it out!), `cmdutil.revert()`'s `parents` argument must be `repo.dirstate.parents()` or things may go wrong. We had an extension that passed in the target commit as the first parent. The `hg split` command from the evolve extension seems to have made the same mistake, but I haven't looked carefully. The problem is that `cmdutil._performrevert()` calls `dirstate.normal()` on reverted files if the commit to revert to equals the first parent. So if you pass in `ctx=foo` and `parents=(foo.node(), nullid)`, then `dirstate.normal()` will be called for the revert files, even though they might not be clean in the working copy. There doesn't seem to be any reason, other than a tiny performance benefit, to passing the `parents` around instead of looking them up again in `cmdutil._performrevert()`, so that's what this patch does. Differential Revision: https://phab.mercurial-scm.org/D8925

--- a/mercurial/subrepo.py	Mon Aug 10 18:08:15 2020 -0700
+++ b/mercurial/subrepo.py	Mon Aug 10 21:46:47 2020 -0700
@@ -986,12 +986,11 @@
 
     def filerevert(self, *pats, **opts):
         ctx = self._repo[opts['rev']]
-        parents = self._repo.dirstate.parents()
         if opts.get('all'):
             pats = [b'set:modified()']
         else:
             pats = []
-        cmdutil.revert(self.ui, self._repo, ctx, parents, *pats, **opts)
+        cmdutil.revert(self.ui, self._repo, ctx, *pats, **opts)
 
     def shortid(self, revid):
         return revid[:12]