repoview: filter tags to non-existent nodes from blockers (issue4328) stable

repoview: filter tags to non-existent nodes from blockers (issue4328)

--- a/mercurial/repoview.py	Mon Aug 11 23:45:08 2014 -0400
+++ b/mercurial/repoview.py	Tue Aug 12 02:40:42 2014 -0500
@@ -41,7 +41,8 @@
         tags = {}
         tagsmod.readlocaltags(repo.ui, repo, tags, {})
         if tags:
-            blockers.extend(cl.rev(t[0]) for t in tags.values())
+            rev, nodemap = cl.rev, cl.nodemap
+            blockers.extend(rev(t[0]) for t in tags.values() if t[0] in nodemap)
     return blockers
 
 def computehidden(repo):