Add flake8 linting in ci and clean up style issues (#230)

* Fix whitespace to match flake8.

* Fix imports to appease flake8.

* Rename things to match pep8.

* Simplify check for nbagg.transparent.

`rcParams` is a `dict`, so there's no need for the roundabout
`set(rcParams.keys())`.

* Add flake8 linting via reviewdog and GitHub Actions.

Author: QuLogic

.github/workflows/reviewdog.yml

@@ -14,3 +14,30 @@ jobs:
           github_token: ${{ secrets.GITHUB_TOKEN }}
           reporter: github-check
           workdir: 'js'
+
+  flake8:
+    name: flake8
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+
+      - name: Set up Python 3
+        uses: actions/setup-python@v1
+        with:
+          python-version: 3.8
+
+      - name: Install flake8
+        run: pip3 install flake8
+
+      - name: Set up reviewdog
+        run: |
+          mkdir -p $HOME/bin
+          curl -sfL \
+            https://github.com/reviewdog/reviewdog/raw/master/install.sh | \
+              sh -s -- -b $HOME/bin
+          echo ::add-path::$HOME/bin
+
+      - name: Run flake8
+        env:
+          REVIEWDOG_GITHUB_API_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+        run: flake8 | reviewdog -f=pep8 -name=flake8 -reporter=github-check

ipympl/__init__.py

@@ -1,8 +1,9 @@
 import sys
-from ._version import version_info, __version__
+from ._version import version_info, __version__  # noqa
 
 npm_pkg_name = 'jupyter-matplotlib'
 
+
 def _jupyter_nbextension_paths():
     return [{
         'section': 'notebook',

ipympl/backend_nbagg.py

@@ -36,7 +36,6 @@
 }
 
 
-
 class Show(ShowBase):
 
     def __call__(self, block=None):
@@ -61,8 +60,10 @@ def __call__(self, block=None):
             if not interactive and manager in Gcf._activeQue:
                 Gcf._activeQue.remove(manager)
 
+
 show = Show()
 
+
 def draw_if_interactive():
     import matplotlib._pylab_helpers as pylab_helpers
 
@@ -71,6 +72,7 @@ def draw_if_interactive():
         if manager is not None:
             manager.show()
 
+
 def connection_info():
     """
     Return a string showing the figure and connection status for
@@ -101,13 +103,16 @@ class Toolbar(DOMWidget, NavigationToolbar2WebAgg):
     _view_name = Unicode('ToolbarView').tag(sync=True)
 
     toolitems = List().tag(sync=True)
-    orientation = Enum(['horizontal', 'vertical'], default_value='vertical').tag(sync=True)
+    orientation = Enum(['horizontal', 'vertical'],
+                       default_value='vertical').tag(sync=True)
     button_style = CaselessStrEnum(
-        values=['primary', 'success', 'info', 'warning', 'danger', ''], default_value='',
+        values=['primary', 'success', 'info', 'warning', 'danger', ''],
+        default_value='',
         help="""Use a predefined styling for the button.""").tag(sync=True)
     collapsed = Bool(True).tag(sync=True)
 
-    _current_action = Enum(values=['pan', 'zoom', ''], default_value='').tag(sync=True)
+    _current_action = Enum(values=['pan', 'zoom', ''],
+                           default_value='').tag(sync=True)
 
     def __init__(self, canvas, *args, **kwargs):
         DOMWidget.__init__(self, *args, **kwargs)
@@ -119,7 +124,8 @@ def export(self):
         buf = io.BytesIO()
         self.canvas.figure.savefig(buf, format='png', dpi='figure')
         # Figure width in pixels
-        pwidth = self.canvas.figure.get_figwidth() * self.canvas.figure.get_dpi()
+        pwidth = (self.canvas.figure.get_figwidth() *
+                  self.canvas.figure.get_dpi())
         # Scale size to match widget on HiPD monitors
         width = pwidth / self.canvas._dpi_ratio
         data = "<img src='data:image/png;base64,{0}' width={1}/>"
@@ -138,7 +144,8 @@ def _default_toolitems(self):
             'export': 'file-picture-o'
         }
 
-        download_item = ('Download', 'Download plot', 'download', 'save_figure')
+        download_item = ('Download', 'Download plot', 'download',
+                         'save_figure')
 
         toolitems = (NavigationToolbar2.toolitems + (download_item,))
 
@@ -158,9 +165,11 @@ class Canvas(DOMWidget, FigureCanvasWebAggCore):
     _view_module_version = Unicode(js_semver).tag(sync=True)
     _view_name = Unicode('MPLCanvasView').tag(sync=True)
 
-    toolbar = Instance(Toolbar, allow_none=True).tag(sync=True, **widget_serialization)
+    toolbar = Instance(Toolbar,
+                       allow_none=True).tag(sync=True, **widget_serialization)
     toolbar_visible = Bool(True).tag(sync=True)
-    toolbar_position = Enum(['top', 'bottom', 'left', 'right'], default_value='left').tag(sync=True)
+    toolbar_position = Enum(['top', 'bottom', 'left', 'right'],
+                            default_value='left').tag(sync=True)
 
     header_visible = Bool(True).tag(sync=True)
     footer_visible = Bool(True).tag(sync=True)
@@ -270,9 +279,9 @@ def new_figure_manager(num, *args, **kwargs):
     """
     Create a new figure manager instance
     """
-    FigureClass = kwargs.pop('FigureClass', Figure)
-    thisFig = FigureClass(*args, **kwargs)
-    return new_figure_manager_given_figure(num, thisFig)
+    figure_class = kwargs.pop('FigureClass', Figure)
+    this_fig = figure_class(*args, **kwargs)
+    return new_figure_manager_given_figure(num, this_fig)
 
 
 def new_figure_manager_given_figure(num, figure):
@@ -285,7 +294,7 @@ def closer(event):
         Gcf.destroy(num)
 
     canvas = Canvas(figure)
-    if 'nbagg.transparent' in set(rcParams.keys()) and rcParams['nbagg.transparent']:
+    if 'nbagg.transparent' in rcParams and rcParams['nbagg.transparent']:
         figure.patch.set_alpha(0)
     manager = FigureManager(canvas, num)
 

setup.py

@@ -1,4 +1,5 @@
 from __future__ import print_function
+from distutils import log
 from setuptools import setup, find_packages, Command
 from setuptools.command.sdist import sdist
 from setuptools.command.build_py import build_py
@@ -15,15 +16,15 @@
 
 npm_path = os.pathsep.join([
     pjoin(node_root, 'node_modules', '.bin'),
-            os.environ.get('PATH', os.defpath),
+    os.environ.get('PATH', os.defpath),
 ])
 
-from distutils import log
 log.info('setup.py entered')
 log.info('$PATH=%s' % os.environ['PATH'])
 
 LONG_DESCRIPTION = 'Matplotlib Jupyter Extension'
 
+
 def js_prerelease(command, strict=False):
     """decorator for building minified js/css prior to another command"""
     class DecoratedCommand(command):
@@ -50,6 +51,7 @@ def run(self):
             update_package_data(self.distribution)
     return DecoratedCommand
 
+
 def update_package_data(distribution):
     """update package_data to catch changes during setup"""
     build_py = distribution.get_command_obj('build_py')
@@ -106,21 +108,26 @@ def has_npm(self):
     def run(self):
         has_npm = self.has_npm()
         if not has_npm:
-            log.error("`npm` unavailable.  If you're running this command using sudo, make sure `npm` is available to sudo")
+            log.error("`npm` unavailable.  If you're running this command "
+                      "using sudo, make sure `npm` is available to sudo")
 
         env = os.environ.copy()
         env['PATH'] = npm_path
 
         if self.has_npm():
-            log.info("Installing build dependencies with npm.  This may take a while...")
-            check_call(['npm', 'install'], cwd=node_root, stdout=sys.stdout, stderr=sys.stderr)
-            check_call(['npm', 'pack'], cwd=node_root, stdout=sys.stdout, stderr=sys.stderr)
+            log.info("Installing build dependencies with npm.  "
+                     "This may take a while...")
+            check_call(['npm', 'install'], cwd=node_root, stdout=sys.stdout,
+                       stderr=sys.stderr)
+            check_call(['npm', 'pack'], cwd=node_root, stdout=sys.stdout,
+                       stderr=sys.stderr)
 
         for t in self.targets:
             if not os.path.exists(t):
                 msg = 'Missing file: %s' % t
                 if not has_npm:
-                    msg += '\nnpm is required to build a development version of widgetsnbextension'
+                    msg += ('\nnpm is required to build a development version '
+                            'of widgetsnbextension')
                 raise ValueError(msg)
 
         # update package data in case this created new files