Run flake and remove deprecated import

.pre-commit-config.yaml

@@ -34,16 +34,16 @@ repos:
     hooks:
       - id: prettier
 
-  # - repo: https://github.com/pycqa/flake8
-  #   rev: 4.0.1
-  #   hooks:
-  #     - id: flake8
-  #       additional_dependencies:
-  #         [
-  #           "flake8-bugbear==20.1.4",
-  #           "flake8-logging-format==0.6.0",
-  #           "flake8-implicit-str-concat==0.2.0",
-  #         ]
+  - repo: https://github.com/pycqa/flake8
+    rev: 4.0.1
+    hooks:
+      - id: flake8
+        additional_dependencies:
+          [
+            "flake8-bugbear==20.1.4",
+            "flake8-logging-format==0.6.0",
+            "flake8-implicit-str-concat==0.2.0",
+          ]
 
   - repo: https://github.com/pre-commit/mirrors-eslint
     rev: v8.12.0

docs/conf.py

@@ -217,16 +217,7 @@
 
 # -- Options for LaTeX output ---------------------------------------------
 
-latex_elements = {
-    # The paper size ('letterpaper' or 'a4paper').
-    #'papersize': 'letterpaper',
-    # The font size ('10pt', '11pt' or '12pt').
-    #'pointsize': '10pt',
-    # Additional stuff for the LaTeX preamble.
-    #'preamble': '',
-    # Latex figure (float) alignment
-    #'figure_align': 'htbp',
-}
+latex_elements = {}
 
 # Grouping the document tree into LaTeX files. List of tuples
 # (source start file, target name, title,

examples/embedding/internal_ipkernel.py

@@ -19,7 +19,7 @@ def mpl_kernel(gui):
         [
             "python",
             "--matplotlib=%s" % gui,
-            #'--log-level=10'
+            #'--log-level=10'  # noqa
         ]
     )
     return kernel

ipykernel/__init__.py

@@ -1,7 +1,5 @@
-from ._version import (
-    __version__,
-    kernel_protocol_version,
-    kernel_protocol_version_info,
-    version_info,
-)
-from .connect import *
+from ._version import __version__  # noqa
+from ._version import kernel_protocol_version  # noqa
+from ._version import kernel_protocol_version_info  # noqa
+from ._version import version_info  # noqa
+from .connect import *  # noqa

ipykernel/comm/__init__.py

@@ -1,2 +1,2 @@
-from .comm import *
-from .manager import *
+from .comm import *  # noqa
+from .manager import *  # noqa

ipykernel/compiler.py

@@ -43,7 +43,7 @@ def murmur2_x86(data, seed):
     return h
 
 
-convert_to_long_pathname = lambda filename: filename
+convert_to_long_pathname = lambda filename: filename  # noqa
 
 if sys.platform == "win32":
     try:
@@ -63,7 +63,7 @@ def _convert_to_long_pathname(filename):
 
         # test that it works so if there are any issues we fail just once here
         _convert_to_long_pathname(__file__)
-    except:
+    except Exception:
         pass
     else:
         convert_to_long_pathname = _convert_to_long_pathname

ipykernel/debugger.py

@@ -1,7 +1,6 @@
 import os
 import re
 import sys
-import threading
 
 import zmq
 from IPython.core.getipython import get_ipython

ipykernel/eventloops.py

@@ -128,12 +128,12 @@ def loop_qt5(kernel):
     """Start a kernel with PyQt5 event loop integration."""
     if os.environ.get("QT_API", None) is None:
         try:
-            import PyQt5
+            import PyQt5  # noqa
 
             os.environ["QT_API"] = "pyqt5"
         except ImportError:
             try:
-                import PySide2
+                import PySide2  # noqa
 
                 os.environ["QT_API"] = "pyside2"
             except ImportError:

ipykernel/inprocess/__init__.py

@@ -1,4 +1,4 @@
-from .blocking import BlockingInProcessKernelClient
-from .channels import InProcessChannel, InProcessHBChannel
-from .client import InProcessKernelClient
-from .manager import InProcessKernelManager
+from .blocking import BlockingInProcessKernelClient  # noqa
+from .channels import InProcessChannel, InProcessHBChannel  # noqa
+from .client import InProcessKernelClient  # noqa
+from .manager import InProcessKernelManager  # noqa

ipykernel/inprocess/client.py

@@ -99,15 +99,15 @@ def hb_channel(self):
     # -------------------------------------
 
     def execute(
-        self, code, silent=False, store_history=True, user_expressions={}, allow_stdin=None
+        self, code, silent=False, store_history=True, user_expressions=None, allow_stdin=None
     ):
         if allow_stdin is None:
             allow_stdin = self.allow_stdin
         content = dict(
             code=code,
             silent=silent,
             store_history=store_history,
-            user_expressions=user_expressions,
+            user_expressions=user_expressions or {},
             allow_stdin=allow_stdin,
         )
         msg = self.session.msg("execute_request", content)

ipykernel/inprocess/tests/test_kernel.py

@@ -64,7 +64,7 @@ def setUp(self):
 
     def test_pylab(self):
         """Does %pylab work in the in-process kernel?"""
-        matplotlib = pytest.importorskip("matplotlib", reason="This test requires matplotlib")
+        _ = pytest.importorskip("matplotlib", reason="This test requires matplotlib")
         kc = self.kc
         kc.execute("%pylab")
         out, err = assemble_output(kc.get_iopub_msg)

ipykernel/iostream.py

@@ -12,7 +12,6 @@
 import warnings
 from binascii import b2a_hex
 from collections import deque
-from imp import lock_held as import_lock_held
 from io import StringIO, TextIOBase
 from weakref import WeakSet
 
@@ -122,7 +121,7 @@ def _handle_event(self, msg):
         # freeze event count so new writes don't extend the queue
         # while we are processing
         n_events = len(self._events)
-        for i in range(n_events):
+        for _ in range(n_events):
             event_f = self._events.popleft()
             event_f()
 
@@ -475,16 +474,13 @@ def flush(self):
             # request flush on the background thread
             self.pub_thread.schedule(self._flush)
             # wait for flush to actually get through, if we can.
-            # waiting across threads during import can cause deadlocks
-            # so only wait if import lock is not held
-            if not import_lock_held():
-                evt = threading.Event()
-                self.pub_thread.schedule(evt.set)
-                # and give a timeout to avoid
-                if not evt.wait(self.flush_timeout):
-                    # write directly to __stderr__ instead of warning because
-                    # if this is happening sys.stderr may be the problem.
-                    print("IOStream.flush timed out", file=sys.__stderr__)
+            evt = threading.Event()
+            self.pub_thread.schedule(evt.set)
+            # and give a timeout to avoid
+            if not evt.wait(self.flush_timeout):
+                # write directly to __stderr__ instead of warning because
+                # if this is happening sys.stderr may be the problem.
+                print("IOStream.flush timed out", file=sys.__stderr__)
         else:
             self._flush()
 

ipykernel/ipkernel.py

@@ -307,9 +307,10 @@ async def do_execute(
             run_cell = shell.run_cell_async
             should_run_async = shell.should_run_async
         else:
-            should_run_async = lambda cell: False
+            should_run_async = lambda cell: False  # noqa
             # older IPython,
             # use blocking run_cell and wrap it in coroutine
+
             async def run_cell(*args, **kwargs):
                 return shell.run_cell(*args, **kwargs)
 

ipykernel/kernelbase.py

@@ -942,7 +942,7 @@ async def usage_request(self, stream, ident, parent):
         cpu_percent = psutil.cpu_percent()
         # https://psutil.readthedocs.io/en/latest/index.html?highlight=cpu#psutil.cpu_percent
         # The first time cpu_percent is called it will return a meaningless 0.0 value which you are supposed to ignore.
-        if cpu_percent != None and cpu_percent != 0.0:
+        if cpu_percent is not None and cpu_percent != 0.0:
             reply_content["host_cpu_percent"] = cpu_percent
         reply_content["host_virtual_memory"] = dict(psutil.virtual_memory()._asdict())
         reply_msg = self.session.send(stream, "usage_reply", reply_content, parent, ident)
@@ -1083,7 +1083,7 @@ def _no_raw_input(self):
         """Raise StdinNotImplementedError if active frontend doesn't support
         stdin."""
         raise StdinNotImplementedError(
-            "raw_input was called, but this " "frontend does not support stdin."
+            "raw_input was called, but this frontend does not support stdin."
         )
 
     def getpass(self, prompt="", stream=None):

ipykernel/pickleutil.py

@@ -118,7 +118,7 @@ def use_cloudpickle():
 
 
 class CannedObject:
-    def __init__(self, obj, keys=[], hook=None):
+    def __init__(self, obj, keys=None, hook=None):
         """can an object for safe pickling
 
         Parameters
@@ -136,7 +136,7 @@ def __init__(self, obj, keys=[], hook=None):
         large data may be offloaded into the buffers list,
         used for zero-copy transfers.
         """
-        self.keys = keys
+        self.keys = keys or []
         self.obj = copy.copy(obj)
         self.hook = can(hook)
         for key in keys:
@@ -326,7 +326,7 @@ def _import_mapping(mapping, original=None):
     """import any string-keys in a type mapping"""
     log = get_logger()
     log.debug("Importing canning map")
-    for key, value in list(mapping.items()):
+    for key, _ in list(mapping.items()):
         if isinstance(key, str):
             try:
                 cls = import_item(key)

ipykernel/pylab/config.py

@@ -8,6 +8,6 @@
 from matplotlib_inline.config import *  # analysis: ignore # noqa F401
 
 warnings.warn(
-    "`ipykernel.pylab.config` is deprecated, directly " "use `matplotlib_inline.config`",
+    "`ipykernel.pylab.config` is deprecated, directly use `matplotlib_inline.config`",
     DeprecationWarning,
 )

ipykernel/serialize.py

@@ -189,7 +189,7 @@ def unpack_apply_message(bufs, g=None, copy=True):
     arg_bufs, kwarg_bufs = bufs[: info["narg_bufs"]], bufs[info["narg_bufs"] :]
 
     args = []
-    for i in range(info["nargs"]):
+    for _ in range(info["nargs"]):
         arg, arg_bufs = deserialize_object(arg_bufs, g)
         args.append(arg)
     args = tuple(args)

ipykernel/tests/__init__.py

@@ -7,9 +7,6 @@
 import tempfile
 from unittest.mock import patch
 
-from IPython import paths as ipaths
-from jupyter_core import paths as jpaths
-
 from ipykernel.kernelspec import install
 
 pjoin = os.path.join

ipykernel/tests/test_async.py

@@ -1,9 +1,5 @@
 """Test async/await integration"""
 
-import sys
-from distutils.version import LooseVersion as V
-
-import IPython
 import pytest
 
 from .test_message_spec import validate_message

ipykernel/tests/test_connect.py

@@ -35,7 +35,7 @@ class DummyKernelApp(IPKernelApp):
     def _default_shell_port(self):
         return 0
 
-    def initialize(self, argv=[]):
+    def initialize(self, argv=None):
         self.init_profile_dir()
         self.init_connection_file()
 

ipykernel/tests/test_embed_kernel.py

@@ -164,7 +164,7 @@ def test_embed_kernel_reentrant():
             "    embed_kernel()",
             "    count = count + 1",
             "",
-            "while True:" "    go()",
+            "while True:    go()",
             "",
         ]
     )

ipykernel/tests/test_eventloop.py

@@ -1,7 +1,5 @@
 """Test eventloop integration"""
 
-import sys
-
 import pytest
 import tornado
 

ipykernel/tests/test_kernel.py

@@ -336,7 +336,7 @@ def test_message_order():
         cell = "a += 1\na"
         msg_ids = []
         # submit N executions as fast as we can
-        for i in range(N):
+        for _ in range(N):
             msg_ids.append(kc.execute(cell))
         # check message-handling order
         for i, msg_id in enumerate(msg_ids, offset):
@@ -388,7 +388,7 @@ def test_shutdown():
         execute("a = 1", kc=kc)
         wait_for_idle(kc)
         kc.shutdown()
-        for i in range(300):  # 30s timeout
+        for _ in range(300):  # 30s timeout
             if km.is_alive():
                 time.sleep(0.1)
             else:
@@ -482,7 +482,7 @@ def test_control_thread_priority():
 
         # now send N control messages
         control_msg_ids = []
-        for i in range(N):
+        for _ in range(N):
             msg = kc.session.msg("kernel_info_request", {})
             kc.control_channel.send(msg)
             control_msg_ids.append(msg["header"]["msg_id"])
@@ -557,7 +557,7 @@ def test_shutdown_subprocesses():
         wait_for_idle(kc)
 
         kc.shutdown()
-        for i in range(300):  # 30s timeout
+        for _ in range(300):  # 30s timeout
             if km.is_alive():
                 time.sleep(0.1)
             else:

ipykernel/tests/test_message_spec.py

@@ -528,7 +528,7 @@ def test_single_payload():
     """
     flush_channels()
     msg_id, reply = execute(
-        code="ip = get_ipython()\n" "for i in range(3):\n" "   ip.set_next_input('Hello There')\n"
+        code="ip = get_ipython()\nfor i in range(3):\n   ip.set_next_input('Hello There')\n"
     )
     payload = reply["payload"]
     next_input_pls = [pl for pl in payload if pl["source"] == "set_next_input"]

ipykernel/tests/utils.py

@@ -5,7 +5,6 @@
 
 import atexit
 import os
-import platform
 import sys
 from contextlib import contextmanager
 from queue import Empty

ipykernel/trio_runner.py

@@ -17,7 +17,7 @@ def initialize(self, kernel, io_loop):
         kernel.shell.set_trio_runner(self)
         kernel.shell.run_line_magic("autoawait", "trio")
         kernel.shell.magics_manager.magics["line"]["autoawait"] = lambda _: warnings.warn(
-            "Autoawait isn't allowed in Trio " "background loop mode."
+            "Autoawait isn't allowed in Trio background loop mode."
         )
         bg_thread = threading.Thread(target=io_loop.start, daemon=True, name="TornadoBackground")
         bg_thread.start()

ipykernel/zmqshell.py

@@ -205,7 +205,7 @@ class KernelMagics(Magics):
     _find_edit_target = CodeMagics._find_edit_target
 
     @line_magic
-    def edit(self, parameter_s="", last_call=["", ""]):
+    def edit(self, parameter_s="", last_call=None):
         """Bring up an editor and execute the resulting code.
 
         Usage:
@@ -281,7 +281,7 @@ def edit(self, parameter_s="", last_call=["", ""]):
 
         Note that %edit is also available through the alias %ed.
         """
-
+        last_call = last_call or ["", ""]
         opts, args = self.parse_options(parameter_s, "prn:")
 
         try: