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/commands.py	Mon Aug 10 18:08:15 2020 -0700
+++ b/mercurial/commands.py	Mon Aug 10 21:46:47 2020 -0700
@@ -837,7 +837,7 @@
     else:
         hg.clean(repo, node, show_stats=False)
         repo.dirstate.setbranch(branch)
-        cmdutil.revert(ui, repo, rctx, repo.dirstate.parents())
+        cmdutil.revert(ui, repo, rctx)
 
     if opts.get(b'no_commit'):
         msg = _(b"changeset %s backed out, don't forget to commit.\n")
@@ -6301,9 +6301,7 @@
             hint = _(b"use --all to revert all files")
         raise error.Abort(msg, hint=hint)
 
-    return cmdutil.revert(
-        ui, repo, ctx, (parent, p2), *pats, **pycompat.strkwargs(opts)
-    )
+    return cmdutil.revert(ui, repo, ctx, *pats, **pycompat.strkwargs(opts))
 
 
 @command(