diff -r 2ff8994ac71d -r 5cb8158a61f7 hgext/transplant.py
--- a/hgext/transplant.py	Fri Jan 25 23:43:11 2019 -0800
+++ b/hgext/transplant.py	Fri Jan 25 23:22:23 2019 -0800
@@ -155,7 +155,7 @@
         if opts is None:
             opts = {}
         revs = sorted(revmap)
-        p1, p2 = repo.dirstate.parents()
+        p1 = repo.dirstate.p1()
         pulls = []
         diffopts = patch.difffeatureopts(self.ui, opts)
         diffopts.git = True
@@ -186,7 +186,7 @@
                             exchange.pull(repo, source.peer(), heads=pulls)
                         merge.update(repo, pulls[-1], branchmerge=False,
                                      force=False)
-                        p1, p2 = repo.dirstate.parents()
+                        p1 = repo.dirstate.p1()
                         pulls = []
 
                 domerge = False
@@ -323,7 +323,7 @@
         else:
             files = None
         if merge:
-            p1, p2 = repo.dirstate.parents()
+            p1 = repo.dirstate.p1()
             repo.setparents(p1, node)
             m = match.always(repo.root, '')
         else:
@@ -387,7 +387,7 @@
 
         extra = {'transplant_source': node}
         try:
-            p1, p2 = repo.dirstate.parents()
+            p1 = repo.dirstate.p1()
             if p1 != parent:
                 raise error.Abort(_('working directory not at transplant '
                                    'parent %s') % nodemod.hex(parent))
@@ -668,7 +668,7 @@
 
     tp = transplanter(ui, repo, opts)
 
-    p1, p2 = repo.dirstate.parents()
+    p1 = repo.dirstate.p1()
     if len(repo) > 0 and p1 == revlog.nullid:
         raise error.Abort(_('no revision checked out'))
     if opts.get('continue'):