Remove unused IPython.utils.rlineimpl readline module

Also deprecate the use_readline parameter for IPCompleter

IPython/core/completer.py

@@ -25,6 +25,7 b' import re'
 import sys
 import unicodedata
 import string
+import warnings
 
 from traitlets.config.configurable import Configurable
 from IPython.core.error import TryNext
@@ -589,7 +590,7 b' class IPCompleter(Completer):'
     ).tag(config=True)
 
     def __init__(self, shell=None, namespace=None, global_namespace=None,
-                 use_readline=True, config=None, **kwargs):
+                 use_readline=False, config=None, **kwargs):
         """IPCompleter() -> completer
 
         Return a completer object suitable for use by the readline library
@@ -608,20 +609,15 b' class IPCompleter(Completer):'
           both Python scopes are visible.
 
         use_readline : bool, optional
-          If true, use the readline library.  This completer can still function
-          without readline, though in that case callers must provide some extra
-          information on each call about the current line."""
+          DEPRECATED, ignored.
+        """
 
         self.magic_escape = ESC_MAGIC
         self.splitter = CompletionSplitter()
 
-        # Readline configuration, only used by the rlcompleter method.
         if use_readline:
-            # We store the right version of readline so that later code
-            import IPython.utils.rlineimpl as readline
-            self.readline = readline
-        else:
-            self.readline = None
+            warnings.warn('The use_readline parameter is deprecated since IPython 6.0.',
+                          DeprecationWarning, stacklevel=2)
 
         # _greedy_changed() depends on splitter and readline being defined:
         Completer.__init__(self, namespace=namespace, global_namespace=global_namespace,

IPython/core/interactiveshell.py

@@ -1905,7 +1905,6 b' class InteractiveShell(SingletonConfigurable):'
         self.Completer = IPCompleter(shell=self,
                                      namespace=self.user_ns,
                                      global_namespace=self.user_global_ns,
-                                     use_readline=False,
                                      parent=self,
                                      )
         self.configurables.append(self.Completer)

IPython/terminal/debugger.py

@@ -24,7 +24,6 b' class TerminalPdb(Pdb):'
             compl = IPCompleter(shell=self.shell,
                                         namespace={},
                                         global_namespace={},
-                                        use_readline=False,
                                         parent=self.shell,
                                        )
             self._ptcomp = IPythonPTCompleter(compl)

IPython/utils/tests/test_imports.py

@@ -12,9 +12,6 b' def test_import_ipstruct():'
 def test_import_PyColorize():
     from IPython.utils import PyColorize
 
-def test_import_rlineimpl():
-    from IPython.utils import rlineimpl
-
 def test_import_strdispatch():
     from IPython.utils import strdispatch