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

hgext/histedit.py

@@ -635,12 +635,11 def commitfuncfor(repo, src):
 
 def applychanges(ui, repo, ctx, opts):
     """Merge changeset from ctx (only) in the current working directory"""
-    wcpar = repo.dirstate.p1()
-    if ctx.p1().node() == wcpar:
+    if ctx.p1().node() == repo.dirstate.p1():
         # edits are "in place" we do not need to make any merge,
         # just applies changes on parent for editing
         ui.pushbuffer()
-        cmdutil.revert(ui, repo, ctx, (wcpar, node.nullid), all=True)
+        cmdutil.revert(ui, repo, ctx, all=True)
         stats = mergemod.updateresult(0, 0, 0, 0)
         ui.popbuffer()
     else:

hgext/largefiles/overrides.py

@@ -874,7 +874,7 def overridecopy(orig, ui, repo, pats, o
 # the matcher to hit standins instead of largefiles. Based on the
 # resulting standins update the largefiles.
 @eh.wrapfunction(cmdutil, b'revert')
-def overriderevert(orig, ui, repo, ctx, parents, *pats, **opts):
+def overriderevert(orig, ui, repo, ctx, *pats, **opts):
     # Because we put the standins in a bad state (by updating them)
     # and then return them to a correct state we need to lock to
     # prevent others from changing them in their incorrect state.
@@ -937,7 +937,7 def overriderevert(orig, ui, repo, ctx,
             return m
 
         with extensions.wrappedfunction(scmutil, b'match', overridematch):
-            orig(ui, repo, ctx, parents, *pats, **opts)
+            orig(ui, repo, ctx, *pats, **opts)
 
         newstandins = lfutil.getstandinsstate(repo)
         filelist = lfutil.getlfilestoupdate(oldstandins, newstandins)

hgext/mq.py

@@ -1717,11 +1717,7 class queue(object):
             except:  # re-raises
                 self.ui.warn(_(b'cleaning up working directory...\n'))
                 cmdutil.revert(
-                    self.ui,
-                    repo,
-                    repo[b'.'],
-                    repo.dirstate.parents(),
-                    no_backup=True,
+                    self.ui, repo, repo[b'.'], no_backup=True,
                 )
                 # only remove unknown files that we know we touched or
                 # created while patching

mercurial/cmdutil.py

@@ -3493,9 +3493,9 def postcommitstatus(repo, pats, opts):
     return repo.status(match=scmutil.match(repo[None], pats, opts))
 
 
-def revert(ui, repo, ctx, parents, *pats, **opts):
+def revert(ui, repo, ctx, *pats, **opts):
     opts = pycompat.byteskwargs(opts)
-    parent, p2 = parents
+    parent, p2 = repo.dirstate.parents()
     node = ctx.node()
 
     mf = ctx.manifest()
@@ -3781,7 +3781,6 def revert(ui, repo, ctx, parents, *pats
             match = scmutil.match(repo[None], pats)
             _performrevert(
                 repo,
-                parents,
                 ctx,
                 names,
                 uipathfn,
@@ -3807,7 +3806,6 def revert(ui, repo, ctx, parents, *pats
 
 def _performrevert(
     repo,
-    parents,
     ctx,
     names,
     uipathfn,
@@ -3823,7 +3821,7 def _performrevert(
 
     Make sure you have the working directory locked when calling this function.
     """
-    parent, p2 = parents
+    parent, p2 = repo.dirstate.parents()
     node = ctx.node()
     excluded_files = []
 

mercurial/commands.py

@@ -837,7 +837,7 def _dobackout(ui, repo, node=None, rev=
     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 def revert(ui, repo, *pats, **opts):
             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(

mercurial/shelve.py

@@ -772,7 +772,7 def mergefiles(ui, repo, wctx, shelvectx
     with ui.configoverride({(b'ui', b'quiet'): True}):
         hg.update(repo, wctx.node())
         ui.pushbuffer(True)
-        cmdutil.revert(ui, repo, shelvectx, repo.dirstate.parents())
+        cmdutil.revert(ui, repo, shelvectx)
         ui.popbuffer()
 
 

mercurial/subrepo.py

@@ -986,12 +986,11 class hgsubrepo(abstractsubrepo):
 
     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]