Fix IPython.utils.warn API so messages are automatically displayed followed by a newline.

IPython/core/history.py

@@ -137,7 +137,7 b' class HistoryAccessor(Configurable):'
             self.hist_file = self._get_hist_file_name(profile)
 
         if sqlite3 is None and self.enabled:
-            warn("IPython History requires SQLite, your history will not be saved\n")
+            warn("IPython History requires SQLite, your history will not be saved")
             self.enabled = False
         
         if sqlite3 is not None:

IPython/core/interactiveshell.py

@@ -336,7 +336,7 b' class InteractiveShell(SingletonConfigurable):'
             'prompt_out' : 'out_template',
             'prompts_pad_left' : 'justify',
         }
-        warn("InteractiveShell.{name} is deprecated, use PromptManager.{newname}\n".format(
+        warn("InteractiveShell.{name} is deprecated, use PromptManager.{newname}".format(
                 name=name, newname=table[name])
         )
         # protect against weird cases where self.config may not exist:
@@ -721,7 +721,7 b' class InteractiveShell(SingletonConfigurable):'
             return
         
         warn("Attempting to work in a virtualenv. If you encounter problems, please "
-             "install IPython inside the virtualenv.\n")
+             "install IPython inside the virtualenv.")
         if sys.platform == "win32":
             virtual_env = os.path.join(os.environ['VIRTUAL_ENV'], 'Lib', 'site-packages') 
         else:

IPython/frontend/terminal/ipapp.py

@@ -351,7 +351,7 b' class TerminalIPythonApp(BaseIPythonApplication, InteractiveShellApp):'
         """Replace --pylab='inline' with --pylab='auto'"""
         if new == 'inline':
             warn.warn("'inline' not available as pylab backend, "
-                      "using 'auto' instead.\n")
+                      "using 'auto' instead.")
             self.pylab = 'auto'
 
     def start(self):

IPython/lib/inputhook.py

@@ -105,7 +105,7 b' class InputHookManager(object):'
     
     def __init__(self):
         if ctypes is None:
-            warn("IPython GUI event loop requires ctypes, %gui will not be available\n")
+            warn("IPython GUI event loop requires ctypes, %gui will not be available")
             return
         self.PYFUNC = ctypes.PYFUNCTYPE(ctypes.c_int)
         self._apps = {}

IPython/testing/iptest.py

@@ -319,7 +319,7 b' def make_exclude():'
             continue
         fullpath = pjoin(parent, exclusion)
         if not os.path.exists(fullpath) and not glob.glob(fullpath + '.*'):
-            warn("Excluding nonexistent file: %r\n" % exclusion)
+            warn("Excluding nonexistent file: %r" % exclusion)
 
     return exclusions
 

IPython/utils/attic.py

@@ -130,9 +130,9 b' def import_fail_info(mod_name,fns=None):'
     """Inform load failure for a module."""
 
     if fns == None:
-        warn("Loading of %s failed.\n" % (mod_name,))
+        warn("Loading of %s failed." % (mod_name,))
     else:
-        warn("Loading of %s from %s failed.\n" % (fns,mod_name))
+        warn("Loading of %s from %s failed." % (fns,mod_name))
 
 
 class NotGiven: pass

IPython/utils/warn.py

@@ -42,7 +42,7 b' def warn(msg,level=2,exit_val=1):'
 
     if level>0:
         header = ['','','WARNING: ','ERROR: ','FATAL ERROR: ']
-        io.stderr.write('%s%s' % (header[level],msg))
+        print(header[level], msg, sep='', file=io.stderr)
         if level == 4:
             print('Exiting.\n', file=io.stderr)
             sys.exit(exit_val)