diff -r 67567d7f1174 -r 48b30ff742cb hgext3rd/topic/destination.py
--- a/hgext3rd/topic/destination.py	Tue Aug 06 15:06:27 2019 +0200
+++ b/hgext3rd/topic/destination.py	Tue Aug 06 15:06:38 2019 +0200
@@ -13,11 +13,11 @@
 )
 from .evolvebits import builddependencies
 
-def _destmergebranch(orig, repo, action='merge', sourceset=None,
+def _destmergebranch(orig, repo, action=b'merge', sourceset=None,
                      onheadcheck=True, destspace=None):
     # XXX: take destspace into account
     if sourceset is None:
-        p1 = repo['.']
+        p1 = repo[b'.']
     else:
         # XXX: using only the max here is flacky. That code should eventually
         # be updated to take care of the whole sourceset.
@@ -26,11 +26,11 @@
     if common.hastopicext(repo):
         top = p1.topic()
     if top:
-        revs = repo.revs('topic(%s) - obsolete()', top)
+        revs = repo.revs(b'topic(%s) - obsolete()', top)
         deps, rdeps = builddependencies(repo, revs)
         heads = [r for r in revs if not rdeps[r]]
         if onheadcheck and p1.rev() not in heads:
-            raise error.Abort(_("not at topic head, update or explicit"))
+            raise error.Abort(_(b"not at topic head, update or explicit"))
 
         # prune heads above the source
         otherheads = set(heads)
@@ -43,20 +43,20 @@
             # nothing to do at the topic level
             bhead = ngtip(repo, p1.branch(), all=True)
             if not bhead:
-                raise error.NoMergeDestAbort(_("nothing to merge"))
+                raise error.NoMergeDestAbort(_(b"nothing to merge"))
             elif 1 == len(bhead):
                 return bhead[0]
             else:
-                msg = _("branch '%s' has %d heads "
-                        "- please merge with an explicit rev")
-                hint = _("run 'hg heads .' to see heads")
+                msg = _(b"branch '%s' has %d heads "
+                        b"- please merge with an explicit rev")
+                hint = _(b"run 'hg heads .' to see heads")
                 raise error.ManyMergeDestAbort(msg % (p1.branch(), len(bhead)),
                                                hint=hint)
         elif len(otherheads) == 1:
             return otherheads.pop()
         else:
-            msg = _("topic '%s' has %d heads "
-                    "- please merge with an explicit rev") % (top, len(heads))
+            msg = _(b"topic '%s' has %d heads "
+                    b"- please merge with an explicit rev") % (top, len(heads))
             raise error.ManyMergeDestAbort(msg)
     return orig(repo, action, sourceset, onheadcheck, destspace=destspace)
 
@@ -67,23 +67,23 @@
     movemark = node = None
     topic = repo.currenttopic
     if topic:
-        revs = repo.revs('.::topic(%s)', topic)
+        revs = repo.revs(b'.::topic(%s)', topic)
     else:
         revs = []
     if not revs:
         return None, None, None
     node = revs.last()
     if bookmarks.isactivewdirparent(repo):
-        movemark = repo['.'].node()
+        movemark = repo[b'.'].node()
     return node, movemark, None
 
 def desthistedit(orig, ui, repo):
     if not common.hastopicext(repo):
         return None
-    if not (ui.config('histedit', 'defaultrev', None) is None
+    if not (ui.config(b'histedit', b'defaultrev', None) is None
             and repo.currenttopic):
         return orig(ui, repo)
-    revs = repo.revs('::. and stack()')
+    revs = repo.revs(b'::. and stack()')
     if revs:
         return revs.min()
     return None
@@ -107,7 +107,7 @@
 def modsetup(ui):
     """run a uisetup time to install all destinations wrapping"""
     extensions.wrapfunction(destutil, '_destmergebranch', _destmergebranch)
-    bridx = destutil.destupdatesteps.index('branch')
-    destutil.destupdatesteps.insert(bridx, 'topic')
-    destutil.destupdatestepmap['topic'] = _destupdatetopic
+    bridx = destutil.destupdatesteps.index(b'branch')
+    destutil.destupdatesteps.insert(bridx, b'topic')
+    destutil.destupdatestepmap[b'topic'] = _destupdatetopic
     extensions.wrapfunction(destutil, 'desthistedit', desthistedit)