diff --git a/mercurial/changegroup.py b/mercurial/changegroup.py
--- a/mercurial/changegroup.py
+++ b/mercurial/changegroup.py
@@ -42,6 +42,25 @@ def closechunk():
     """return a changegroup chunk header (string) for a zero-length chunk"""
     return struct.pack(">l", 0)
 
+def combineresults(results):
+    """logic to combine 0 or more addchangegroup results into one"""
+    changedheads = 0
+    result = 1
+    for ret in results:
+        # If any changegroup result is 0, return 0
+        if ret == 0:
+            result = 0
+            break
+        if ret < -1:
+            changedheads += ret + 1
+        elif ret > 1:
+            changedheads += ret - 1
+    if changedheads > 0:
+        result = 1 + changedheads
+    elif changedheads < 0:
+        result = -1 + changedheads
+    return result
+
 class nocompress(object):
     def compress(self, x):
         return x
diff --git a/mercurial/exchange.py b/mercurial/exchange.py
--- a/mercurial/exchange.py
+++ b/mercurial/exchange.py
@@ -992,22 +992,8 @@ def _pullbundle2(pullop):
         raise util.Abort('missing support for %s' % exc)
 
     if pullop.fetch:
-        changedheads = 0
-        pullop.cgresult = 1
-        for cg in op.records['changegroup']:
-            ret = cg['return']
-            # If any changegroup result is 0, return 0
-            if ret == 0:
-                pullop.cgresult = 0
-                break
-            if ret < -1:
-                changedheads += ret + 1
-            elif ret > 1:
-                changedheads += ret - 1
-        if changedheads > 0:
-            pullop.cgresult = 1 + changedheads
-        elif changedheads < 0:
-            pullop.cgresult = -1 + changedheads
+        results = [cg['return'] for cg in op.records['changegroup']]
+        pullop.cgresult = changegroup.combineresults(results)
 
     # processing phases change
     for namespace, value in op.records['listkeys']: