Patchwork [03,of,12,V2] bookmarks: rewrite pushing local bookmarks in "commands.push()" by "compare()"

diff --git a/mercurial/bookmarks.py b/mercurial/bookmarks.py
--- a/mercurial/bookmarks.py
+++ b/mercurial/bookmarks.py
@@ -362,6 +362,46 @@ 
     if changed:
         localmarks.write()
 
+def pushtoremote(ui, repo, remote, targets):
+    class InvalidBookmark(KeyError):
+        """Exception raised when specified bookmark doesn't exist on
+        the local or remote repository"""
+
+    def push(b, old, new):
+        r = remote.pushkey('bookmarks', b, old, new)
+        if not r:
+            ui.warn(_('updating bookmark %s failed!\n') % b)
+            return True
+    def export(b, scid, dcid):
+        ui.status(_("exporting bookmark %s\n") % b)
+        if dcid is None:
+            dcid = ''
+        return push(b, dcid, scid)
+    def delete(b, scid, dcid):
+        # treat as "deleted locally"
+        ui.status(_("deleting remote bookmark %s\n") % b)
+        return push(b, dcid, '')
+    def invalid(b, scid, dcid):
+        raise InvalidBookmark(b)
+
+    try:
+        if _execactions(compare(repo, repo._bookmarks,
+                                remote.listkeys('bookmarks'),
+                                srchex=hex, targets=targets),
+                        {'addsrc': export,
+                         'adddst': delete,
+                         'advsrc': export,
+                         'advdst': export,
+                         'diverge': export,
+                         'differ': export,
+                         'invalid': invalid,
+                         }):
+            return 1
+    except InvalidBookmark, inst:
+        ui.warn(_('bookmark %s does not exist on the local '
+                  'or remote repository!\n') % inst.args[0])
+        return 2
+
 def diff(ui, dst, src):
     ui.status(_("searching for changed bookmarks\n"))
 
diff --git a/mercurial/commands.py b/mercurial/commands.py
--- a/mercurial/commands.py
+++ b/mercurial/commands.py
@@ -4698,25 +4698,11 @@ 
     result = not result
 
     if opts.get('bookmark'):
-        rb = other.listkeys('bookmarks')
-        for b in opts['bookmark']:
-            # explicit push overrides remote bookmark if any
-            if b in repo._bookmarks:
-                ui.status(_("exporting bookmark %s\n") % b)
-                new = repo[b].hex()
-            elif b in rb:
-                ui.status(_("deleting remote bookmark %s\n") % b)
-                new = '' # delete
-            else:
-                ui.warn(_('bookmark %s does not exist on the local '
-                          'or remote repository!\n') % b)
-                return 2
-            old = rb.get(b, '')
-            r = other.pushkey('bookmarks', b, old, new)
-            if not r:
-                ui.warn(_('updating bookmark %s failed!\n') % b)
-                if not result:
-                    result = 2
+        bresult = bookmarks.pushtoremote(ui, repo, other, opts['bookmark'])
+        if bresult == 2:
+            return 2
+        if not result and bresult:
+            result = 2
 
     return result