Merge pull request #2792 from tkf/history-unique-protocol

Add key "unique" to history_request protocol

IPython/kernel/zmq/ipkernel.py

@@ -504,9 +504,10 b' class Kernel(Configurable):'
 
         elif hist_access_type == 'search':
             n = parent['content'].get('n')
+            unique = parent['content'].get('unique', False)
             pattern = parent['content']['pattern']
-            hist = self.shell.history_manager.search(pattern, raw=raw,
-                                                     output=output, n=n)
+            hist = self.shell.history_manager.search(
+                pattern, raw=raw, output=output, n=n, unique=unique)
 
         else:
             hist = []

docs/source/development/messaging.txt

@@ -633,9 +633,16 b' Message type: ``history_request``::'
       # If hist_access_type is 'search', get cells matching the specified glob
       # pattern (with * and ? as wildcards).
       'pattern' : str,
+
+      # If hist_access_type is 'search' and unique is true, do not
+      # include duplicated history.  Default is false.
+      'unique' : bool,
       
     }
 
+.. versionadded:: 4.0
+   The key ``unique`` for ``history_request``.
+
 Message type: ``history_reply``::
 
     content = {