Move cast_unicode_py2 calls into HistoryAccessor

IPython/core/history.py

@@ -301,7 +301,8 b' class HistoryAccessor(HistoryAccessorBase):'
         cur = self.db.execute("SELECT session, line, %s FROM %s " %\
                                 (toget, sqlfrom) + sql, params)
         if output:    # Regroup into 3-tuples, and parse JSON
-            return ((ses, lin, (inp, out)) for ses, lin, inp, out in cur)
+            return ((ses, lin, (py3compat.cast_unicode_py2(inp), py3compat.cast_unicode_py2(out)))
+                    for ses, lin, inp, out in cur)
         return cur
 
     @needs_sqlite

IPython/terminal/interactiveshell.py

@@ -239,7 +239,7 b' class TerminalInteractiveShell(InteractiveShell):'
             # Ignore blank lines and consecutive duplicates
             cell = cell.rstrip()
             if cell and (cell != last_cell):
-                history.append(cast_unicode_py2(cell))
+                history.append(cell)
                 last_cell = cell
 
         self._style = self._make_style_from_name_or_cls(self.highlighting_style)