# HG changeset patch
# User Matt Mackall <mpm@selenic.com>
# Date 1447382921 21600
# Node ID 3309714ded262f1bb3e32dd552b01d6926de06d5
# Parent  ef5bab63af85b74914c3e8ea59cf8abf73a8571c# Parent  8a256cee72c890c761918ec1d244b286694ac51b
merge with stable

diff -r ef5bab63af85 -r 3309714ded26 mercurial/tags.py
--- a/mercurial/tags.py	Tue Nov 10 15:08:56 2015 -0800
+++ b/mercurial/tags.py	Thu Nov 12 20:48:41 2015 -0600
@@ -221,9 +221,13 @@
     '''
     filetags, nodelines = _readtaghist(ui, repo, lines, fn, recode=recode,
                                        calcnodelines=calcnodelines)
+    # util.sortdict().__setitem__ is much slower at replacing then inserting
+    # new entries. The difference can matter if there are thousands of tags.
+    # Create a new sortdict to avoid the performance penalty.
+    newtags = util.sortdict()
     for tag, taghist in filetags.items():
-        filetags[tag] = (taghist[-1], taghist[:-1])
-    return filetags
+        newtags[tag] = (taghist[-1], taghist[:-1])
+    return newtags
 
 def _updatetags(filetags, tagtype, alltags, tagtypes):
     '''Incorporate the tag info read from one file into the two