mercurial/scmutil.py

--- a/mercurial/scmutil.py	Mon Aug 20 15:57:03 2018 -0700
+++ b/mercurial/scmutil.py	Sun Aug 05 00:42:07 2018 -0700
@@ -34,6 +34,7 @@
     obsutil,
     pathutil,
     phases,
+    policy,
     pycompat,
     revsetlang,
     similar,
@@ -52,6 +53,8 @@
 else:
     from . import scmposix as scmplatform
 
+parsers = policy.importmod(r'parsers')
+
 termsize = scmplatform.termsize
 
 class status(tuple):
@@ -514,6 +517,24 @@
                 cache['disambiguationrevset'] = revs
         if cl.rev(node) in revs:
             hexnode = hex(node)
+            nodetree = None
+            if cache is not None:
+                nodetree = cache.get('disambiguationnodetree')
+            if not nodetree:
+                try:
+                    nodetree = parsers.nodetree(cl.index, len(revs))
+                except AttributeError:
+                    # no native nodetree
+                    pass
+                else:
+                    for r in revs:
+                        nodetree.insert(r)
+                    if cache is not None:
+                        cache['disambiguationnodetree'] = nodetree
+            if nodetree is not None:
+                length = max(nodetree.shortest(node), minlength)
+                prefix = hexnode[:length]
+                return disambiguate(prefix)
             for length in range(minlength, len(hexnode) + 1):
                 matches = []
                 prefix = hexnode[:length]