Warn that blck transformer will break complete-input detection.

And fix typoes.

IPython/core/inputsplitter.py

@@ -24,6 +24,7 b' import sys'
 import tokenize
 import warnings
 
+from IPython.utils.py3compat import cast_unicode
 from IPython.core.inputtransformer import (leading_indent,
                                            classic_prompt,
                                            ipy_prompt,
@@ -686,6 +687,7 b' class IPythonInputSplitter(InputSplitter):'
         """
 
         # We must ensure all input is pure unicode
+        lines = cast_unicode(lines, self.encoding)
         # ''.splitlines() --> [], but we need to push the empty line to transformers
         lines_list = lines.splitlines()
         if not lines_list:

docs/source/config/inputtransforms.rst

@@ -74,6 +74,13 b' function.'
 Transforming a full block
 -------------------------
 
+.. warning::
+
+    Transforming a full block at once will break the automatic detection of
+    wether a block of code is complete in interface relying on this
+    functionality, as for example terminal IPython. You will need to use a
+    shortcut to force-execute your cells.
+
 Transforming a full block of python code is possible by implementing a
 :class:`~IPython.core.inputtransformer.Inputtransformer` and overwriting the
 ``push`` and ``reset`` methods. The reset method should send the full block of
@@ -108,9 +115,11 b' should give up any code it has accumulated.'
 You may use :meth:`CoroutineInputTransformer.wrap` to simplify the creation of
 such a transformer.
 
-Here is a simple :class:`CoroutineInputTransformer` that can be though of be
+Here is a simple :class:`CoroutineInputTransformer` that can be thought of
 being the identity::
 
+    from IPython.core.inputtransformer import CoroutineInputTransformer
+
     @CoroutineInputTransformer.wrap
     def noop():
         line = ''