Clean python 2 artifacts. Fix #826

examples/embedding/internal_ipkernel.py

@@ -20,7 +20,7 @@ def mpl_kernel(gui):
     return kernel
 
 
-class InternalIPKernel(object):
+class InternalIPKernel:
 
     def init_ipkernel(self, backend):
         # Start IPython kernel with GUI event loop and mpl support

ipykernel/comm/comm.py

@@ -50,7 +50,7 @@ def _default_topic(self):
     def __init__(self, target_name='', data=None, metadata=None, buffers=None, **kwargs):
         if target_name:
             kwargs['target_name'] = target_name
-        super(Comm, self).__init__(**kwargs)
+        super().__init__(**kwargs)
         if self.kernel:
             if self.primary:
                 # I am primary, open my peer.

ipykernel/compiler.py

@@ -59,7 +59,7 @@ def get_file_name(code):
 class XCachingCompiler(CachingCompiler):
 
     def __init__(self, *args, **kwargs):
-        super(XCachingCompiler, self).__init__(*args, **kwargs)
+        super().__init__(*args, **kwargs)
         self.log = None
 
     def get_code_name(self, raw_code, code, number):

ipykernel/debugger.py

@@ -540,7 +540,7 @@ async def richInspectVariables(self, message):
         else:
             # The code has stopped on a breakpoint, we use the setExpression
             # request to get the rich representation of the variable
-            code = "get_ipython().display_formatter.format(" + var_name + ")"
+            code = f"get_ipython().display_formatter.format({var_name})"
             frame_id = message["arguments"]["frameId"]
             seq = message["seq"]
             reply = await self._forward_message(

ipykernel/displayhook.py

@@ -12,7 +12,7 @@
 from jupyter_client.session import extract_header, Session
 
 
-class ZMQDisplayHook(object):
+class ZMQDisplayHook:
     """A simple displayhook that publishes the object's repr over a ZeroMQ
     socket."""
     topic = b'execute_result'

ipykernel/eventloops.py

@@ -229,7 +229,7 @@ def loop_tk(kernel):
     # file handlers are not available on Windows
     if hasattr(app, 'createfilehandler'):
         # A basic wrapper for structural similarity with the Windows version
-        class BasicAppWrapper(object):
+        class BasicAppWrapper:
             def __init__(self, app):
                 self.app = app
                 self.app.withdraw()
@@ -257,7 +257,7 @@ def process_stream_events(stream, *a, **kw):
         # Tk uses milliseconds
         poll_interval = int(1000 * kernel._poll_interval)
 
-        class TimedAppWrapper(object):
+        class TimedAppWrapper:
             def __init__(self, app, func):
                 self.app = app
                 self.app.withdraw()

ipykernel/gui/gtk3embed.py

@@ -23,7 +23,7 @@
 # Classes and functions
 #-----------------------------------------------------------------------------
 
-class GTKEmbed(object):
+class GTKEmbed:
     """A class to embed a kernel into the GTK main event loop.
     """
     def __init__(self, kernel):

ipykernel/gui/gtkembed.py

@@ -21,7 +21,7 @@
 # Classes and functions
 #-----------------------------------------------------------------------------
 
-class GTKEmbed(object):
+class GTKEmbed:
     """A class to embed a kernel into the GTK main event loop.
     """
     def __init__(self, kernel):

ipykernel/inprocess/blocking.py

@@ -23,7 +23,7 @@
 class BlockingInProcessChannel(InProcessChannel):
 
     def __init__(self, *args, **kwds):
-        super(BlockingInProcessChannel, self).__init__(*args, **kwds)
+        super().__init__(*args, **kwds)
         self._in_queue = Queue()
 
     def call_handlers(self, msg):

ipykernel/inprocess/channels.py

@@ -9,12 +9,12 @@
 # Channel classes
 #-----------------------------------------------------------------------------
 
-class InProcessChannel(object):
+class InProcessChannel:
     """Base class for in-process channels."""
     proxy_methods = []
 
     def __init__(self, client=None):
-        super(InProcessChannel, self).__init__()
+        super().__init__()
         self.client = client
         self._is_alive = False
 
@@ -57,7 +57,7 @@ def process_events(self):
 
 
 
-class InProcessHBChannel(object):
+class InProcessHBChannel:
     """A dummy heartbeat channel interface for in-process kernels.
 
     Normally we use the heartbeat to check that the kernel process is alive.
@@ -68,7 +68,7 @@ class InProcessHBChannel(object):
     time_to_dead = 3.0
 
     def __init__(self, client=None):
-        super(InProcessHBChannel, self).__init__()
+        super().__init__()
         self.client = client
         self._is_alive = False
         self._pause = True

ipykernel/inprocess/client.py

@@ -58,12 +58,12 @@ def _default_blocking_class(self):
         return BlockingInProcessKernelClient
 
     def get_connection_info(self):
-        d = super(InProcessKernelClient, self).get_connection_info()
+        d = super().get_connection_info()
         d['kernel'] = self.kernel
         return d
 
     def start_channels(self, *args, **kwargs):
-        super(InProcessKernelClient, self).start_channels()
+        super().start_channels()
         self.kernel.frontends.append(self)
 
     @property

ipykernel/inprocess/ipkernel.py

@@ -69,15 +69,15 @@ def _default_iopub_socket(self):
     stdin_socket = Instance(DummySocket, ())
 
     def __init__(self, **traits):
-        super(InProcessKernel, self).__init__(**traits)
+        super().__init__(**traits)
 
         self._underlying_iopub_socket.observe(self._io_dispatch, names=['message_sent'])
         self.shell.kernel = self
 
     async def execute_request(self, stream, ident, parent):
         """ Override for temporary IO redirection. """
         with self._redirected_io():
-            await super(InProcessKernel, self).execute_request(stream, ident, parent)
+            await super().execute_request(stream, ident, parent)
 
     def start(self):
         """ Override registration of dispatchers for streams. """
@@ -106,7 +106,7 @@ def _input_request(self, prompt, ident, parent, password=False):
                 break
         else:
             logging.error('No frontend found for raw_input request')
-            return str()
+            return ''
 
         # Await a response.
         while self.raw_input_str is None:
@@ -183,13 +183,13 @@ def enable_matplotlib(self, gui=None):
         """Enable matplotlib integration for the kernel."""
         if not gui:
             gui = self.kernel.gui
-        return super(InProcessInteractiveShell, self).enable_matplotlib(gui)
+        return super().enable_matplotlib(gui)
 
     def enable_pylab(self, gui=None, import_all=True, welcome_message=False):
         """Activate pylab support at runtime."""
         if not gui:
             gui = self.kernel.gui
-        return super(InProcessInteractiveShell, self).enable_pylab(gui, import_all,
+        return super().enable_pylab(gui, import_all,
                                                             welcome_message)
 
 InteractiveShellABC.register(InProcessInteractiveShell)

ipykernel/inprocess/manager.py

@@ -71,7 +71,7 @@ def is_alive(self):
 
     def client(self, **kwargs):
         kwargs['kernel'] = self.kernel
-        return super(InProcessKernelManager, self).client(**kwargs)
+        return super().client(**kwargs)
 
 
 #-----------------------------------------------------------------------------

ipykernel/iostream.py

@@ -39,7 +39,7 @@
 #-----------------------------------------------------------------------------
 
 
-class IOPubThread(object):
+class IOPubThread:
     """An object for sending IOPub messages in a background thread
 
     Prevents a blocking main thread from delaying output from threads.
@@ -239,7 +239,7 @@ def _really_send(self, msg, *args, **kwargs):
             ctx.term()
 
 
-class BackgroundSocket(object):
+class BackgroundSocket:
     """Wrapper around IOPub thread that provides zmq send[_multipart]"""
     io_thread = None
 
@@ -250,26 +250,26 @@ def __getattr__(self, attr):
         """Wrap socket attr access for backward-compatibility"""
         if attr.startswith('__') and attr.endswith('__'):
             # don't wrap magic methods
-            super(BackgroundSocket, self).__getattr__(attr)
+            super().__getattr__(attr)
         if hasattr(self.io_thread.socket, attr):
             warnings.warn(
-                "Accessing zmq Socket attribute {attr} on BackgroundSocket"
-                " is deprecated since ipykernel 4.3.0"
-                " use .io_thread.socket.{attr}".format(attr=attr),
+                f"Accessing zmq Socket attribute {attr} on BackgroundSocket"
+                f" is deprecated since ipykernel 4.3.0"
+                f" use .io_thread.socket.{attr}",
                 DeprecationWarning,
                 stacklevel=2,
             )
             return getattr(self.io_thread.socket, attr)
-        super(BackgroundSocket, self).__getattr__(attr)
+        super().__getattr__(attr)
 
     def __setattr__(self, attr, value):
         if attr == 'io_thread' or (attr.startswith('__' and attr.endswith('__'))):
-            super(BackgroundSocket, self).__setattr__(attr, value)
+            super().__setattr__(attr, value)
         else:
             warnings.warn(
-                "Setting zmq Socket attribute {attr} on BackgroundSocket"
-                " is deprecated since ipykernel 4.3.0"
-                " use .io_thread.socket.{attr}".format(attr=attr),
+                f"Setting zmq Socket attribute {attr} on BackgroundSocket"
+                f" is deprecated since ipykernel 4.3.0"
+                f" use .io_thread.socket.{attr}",
                 DeprecationWarning,
                 stacklevel=2,
             )
@@ -484,7 +484,7 @@ def _flush(self):
                 self.echo.flush()
             except OSError as e:
                 if self.echo is not sys.__stderr__:
-                    print("Flush failed: {}".format(e),
+                    print(f"Flush failed: {e}",
                           file=sys.__stderr__)
 
         data = self._flush_buffer()
@@ -517,7 +517,7 @@ def write(self, string: str) -> int:
                 self.echo.write(string)
             except OSError as e:
                 if self.echo is not sys.__stderr__:
-                    print("Write failed: {}".format(e),
+                    print(f"Write failed: {e}",
                           file=sys.__stderr__)
 
         if self.pub_thread is None:

ipykernel/ipkernel.py

@@ -75,7 +75,7 @@ def _user_ns_changed(self, change):
     _sys_eval_input = Any()
 
     def __init__(self, **kwargs):
-        super(IPythonKernel, self).__init__(**kwargs)
+        super().__init__(**kwargs)
 
         # Initialize the Debugger
         if _is_debugpy_available:
@@ -175,13 +175,13 @@ def start(self):
             self.log.warning("debugpy_stream undefined, debugging will not be enabled")
         else:
             self.debugpy_stream.on_recv(self.dispatch_debugpy, copy=False)
-        super(IPythonKernel, self).start()
+        super().start()
 
     def set_parent(self, ident, parent, channel='shell'):
         """Overridden from parent to tell the display hook and output streams
         about the parent message.
         """
-        super(IPythonKernel, self).set_parent(ident, parent, channel)
+        super().set_parent(ident, parent, channel)
         if channel == 'shell':
             self.shell.set_parent(parent)
 
@@ -190,7 +190,7 @@ def init_metadata(self, parent):
 
         Run at the beginning of each execution request.
         """
-        md = super(IPythonKernel, self).init_metadata(parent)
+        md = super().init_metadata(parent)
         # FIXME: remove deprecated ipyparallel-specific code
         # This is required for ipyparallel < 5.0
         md.update({
@@ -591,4 +591,4 @@ def __init__(self, *args, **kwargs):
         import warnings
         warnings.warn('Kernel is a deprecated alias of ipykernel.ipkernel.IPythonKernel',
                       DeprecationWarning)
-        super(Kernel, self).__init__(*args, **kwargs)
+        super().__init__(*args, **kwargs)

ipykernel/kernelapp.py

@@ -247,7 +247,7 @@ def cleanup_connection_file(self):
         self.log.debug("Cleaning up connection file: %s", cf)
         try:
             os.remove(cf)
-        except (IOError, OSError):
+        except OSError:
             pass
 
         self.cleanup_ipc_files()
@@ -257,7 +257,7 @@ def init_connection_file(self):
             self.connection_file = "kernel-%s.json"%os.getpid()
         try:
             self.connection_file = filefind(self.connection_file, ['.', self.connection_dir])
-        except IOError:
+        except OSError:
             self.log.debug("Connection file not found: %s", self.connection_file)
             # This means I own it, and I'll create it in this directory:
             os.makedirs(os.path.dirname(self.abs_connection_file), mode=0o700, exist_ok=True)
@@ -621,7 +621,7 @@ def init_pdb(self):
     @catch_config_error
     def initialize(self, argv=None):
         self._init_asyncio_patch()
-        super(IPKernelApp, self).initialize(argv)
+        super().initialize(argv)
         if self.subapp is not None:
             return
 

ipykernel/kernelbase.py

@@ -207,7 +207,7 @@ def _parent_header(self):
     control_msg_types = msg_types + ['clear_request', 'abort_request', 'debug_request']
 
     def __init__(self, **kwargs):
-        super(Kernel, self).__init__(**kwargs)
+        super().__init__(**kwargs)
         # Build dict of handlers for message types
         self.shell_handlers = {}
         for msg_type in self.msg_types:

ipykernel/parentpoller.py

@@ -22,7 +22,7 @@ class ParentPollerUnix(Thread):
     """
 
     def __init__(self):
-        super(ParentPollerUnix, self).__init__()
+        super().__init__()
         self.daemon = True
 
     def run(self):
@@ -60,7 +60,7 @@ def __init__(self, interrupt_handle=None, parent_handle=None):
             handle is signaled.
         """
         assert(interrupt_handle or parent_handle)
-        super(ParentPollerWindows, self).__init__()
+        super().__init__()
         if ctypes is None:
             raise ImportError("ParentPollerWindows requires ctypes")
         self.daemon = True

ipykernel/pickleutil.py

@@ -110,7 +110,7 @@ def use_cloudpickle():
 #-------------------------------------------------------------------------------
 
 
-class CannedObject(object):
+class CannedObject:
     def __init__(self, obj, keys=[], hook=None):
         """can an object for safe pickling
 

ipykernel/tests/__init__.py

@@ -40,6 +40,6 @@ def teardown():
 
     try:
         shutil.rmtree(tmp)
-    except (OSError, IOError):
+    except OSError:
         # no such file
         pass

ipykernel/tests/test_async.py

@@ -54,7 +54,7 @@ def test_async_interrupt(asynclib, request):
 
     flush_channels(KC)
     msg_id = KC.execute(
-        "print('begin'); import {0}; await {0}.sleep(5)".format(asynclib)
+        f"print('begin'); import {asynclib}; await {asynclib}.sleep(5)"
     )
     busy = KC.get_iopub_msg(timeout=TIMEOUT)
     validate_message(busy, "status", msg_id)