Use Black to format Python code (#6447)

* Format Python code with Black

* Update .flake8 for Black

* Address most flake8 issues

* Fix flake8 E231: missing whitespace after ','

Should be removed by Black, but currently buggy.

See: psf/black#1202

* Re-run Black

* One final black/flake8 fix

* Fail CI if Black does not pass

.flake8

@@ -1,11 +1,19 @@
 [flake8]
-exclude = **/migrations/**,.tox,*.egg,vendor
-# E501 - line too long (82 > 79 characters)
-# E731 - do not assign a lambda expression, use a def
-# F405 - name may be undefined, or defined from star imports: module
-# W504 - line break after binary operator
-#        conflicts with W503 (line break before binary operator)
-ignore = E501,E731,F405,W504
+exclude = **/migrations/**
+
+# Black recommends 88-char lines and ignoring the following lints:
+# - E203 - whitespace before ':'
+# - E501 - line too long
+# - W503 - line break before binary operator
+max-line-length=88
+ignore = E203, E501, W503
+
+# Allow star imports in config files:
+per-file-ignores =
+    kuma/settings/local.py:F403,F405
+    kuma/settings/prod.py:F403,F405
+    kuma/settings/testing.py:F403,F405
+
 # flake8-import-order settings
 import-order-style=edited
-application-import-names=kuma,pages,utils
+application-import-names=kuma,pages,utils

.travis.yml

@@ -26,7 +26,7 @@ matrix:
             - poetry --version
             - poetry install -vv
             - poetry run flake8 kuma docs tests
-            - poetry run black --check kuma docs tests || echo "We're not letting it break things yet"
+            - poetry run black --check --diff kuma docs tests
         - language: python
           name: "Python testing"
           python: 3.8

docs/conf.py

@@ -27,29 +27,29 @@
 extensions = []
 
 # Add any paths that contain templates here, relative to this directory.
-templates_path = ['_templates']
+templates_path = ["_templates"]
 
 # The suffix of source filenames.
-source_suffix = '.rst'
+source_suffix = ".rst"
 
 # The encoding of source files.
 # source_encoding = 'utf-8-sig'
 
 # The master toctree document.
-master_doc = 'index'
+master_doc = "index"
 
 # General information about the project.
-project = 'Kuma'
-copyright = 'Mozilla'
+project = "Kuma"
+copyright = "Mozilla"
 
 # The version info for the project you're documenting, acts as replacement for
 # |version| and |release|, also used in various other places throughout the
 # built documents.
 #
 # The short X.Y version.
-version = 'latest'
+version = "latest"
 # The full version, including alpha/beta/rc tags.
-release = 'latest'
+release = "latest"
 
 # The language for content autogenerated by Sphinx. Refer to documentation
 # for a list of supported languages.
@@ -64,7 +64,7 @@
 
 # List of patterns, relative to source directory, that match files and
 # directories to ignore when looking for source files.
-exclude_patterns = ['_build']
+exclude_patterns = ["_build"]
 
 # The reST default role (used for this markup: `text`) to use for all documents.
 # default_role = None
@@ -94,7 +94,7 @@
 
 # The theme to use for HTML and HTML Help pages.  See the documentation for
 # a list of builtin themes.
-html_theme = 'alabaster'
+html_theme = "alabaster"
 
 # Add any paths that contain custom themes here, relative to this directory.
 html_theme_path = ["."]
@@ -103,26 +103,28 @@
 # further.  For a list of options available for each theme, see the
 # documentation.
 html_theme_options = {
-    'github_user': 'mozilla',
-    'github_repo': 'kuma',
-    'github_button': False,
-    'description': ('The platform that powers '
-                    '<a href="https://developer.mozilla.org/en-US/">MDN</a>'),
-    'travis_button': False,
-    'codecov_button': False,
-    'extra_nav_links': {
-        'MDN': 'https://developer.mozilla.org',
-        'MDN Staging': 'https://developer.allizom.org',
-        'Kuma on GitHub': 'https://github.com/mdn/kuma',
-        'KumaScript on GitHub': 'https://github.com/mdn/kumascript',
+    "github_user": "mozilla",
+    "github_repo": "kuma",
+    "github_button": False,
+    "description": (
+        "The platform that powers "
+        '<a href="https://developer.mozilla.org/en-US/">MDN</a>'
+    ),
+    "travis_button": False,
+    "codecov_button": False,
+    "extra_nav_links": {
+        "MDN": "https://developer.mozilla.org",
+        "MDN Staging": "https://developer.allizom.org",
+        "Kuma on GitHub": "https://github.com/mdn/kuma",
+        "KumaScript on GitHub": "https://github.com/mdn/kumascript",
     },
-    'show_related': True,
-    'page_width': '100%'
+    "show_related": True,
+    "page_width": "100%",
 }
 
 # The name for this set of Sphinx documents.  If None, it defaults to
 # "<project> v<release> documentation".
-html_title = 'Kuma Documentation'
+html_title = "Kuma Documentation"
 
 # A shorter title for the navigation bar.  Default is the same as html_title.
 # html_short_title = None
@@ -151,12 +153,12 @@
 
 # Custom sidebar templates, maps document names to template names.
 html_sidebars = {
-    '**': [
-        'about.html',
-        'navigation.html',
-        'relations.html',
-        'searchbox.html',
-        'donate.html',
+    "**": [
+        "about.html",
+        "navigation.html",
+        "relations.html",
+        "searchbox.html",
+        "donate.html",
     ]
 }
 
@@ -191,27 +193,24 @@
 # html_file_suffix = None
 
 # Output file base name for HTML help builder.
-htmlhelp_basename = 'Kumadoc'
+htmlhelp_basename = "Kumadoc"
 
 
 # -- 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': '',
 }
 
 # Grouping the document tree into LaTeX files. List of tuples
 # (source start file, target name, title, author, documentclass [howto/manual]).
 latex_documents = [
-    ('index', 'Kuma.tex', 'Kuma Documentation',
-     'Mozilla', 'manual'),
+    ("index", "Kuma.tex", "Kuma Documentation", "Mozilla", "manual"),
 ]
 
 # The name of an image file (relative to this directory) to place at the top of
@@ -239,10 +238,7 @@
 
 # One entry per manual page. List of tuples
 # (source start file, name, description, authors, manual section).
-man_pages = [
-    ('index', 'kuma', 'Kuma Documentation',
-     ['Mozilla'], 1)
-]
+man_pages = [("index", "kuma", "Kuma Documentation", ["Mozilla"], 1)]
 
 # If true, show URL addresses after external links.
 # man_show_urls = False
@@ -254,10 +250,15 @@
 # (source start file, target name, title, author,
 #  dir menu entry, description, category)
 texinfo_documents = [
-    ('index', 'Kuma', 'Kuma Documentation',
-     'Mozilla', 'Kuma',
-     'The Django based project of developer.mozilla.org.',
-     'Miscellaneous'),
+    (
+        "index",
+        "Kuma",
+        "Kuma Documentation",
+        "Mozilla",
+        "Kuma",
+        "The Django based project of developer.mozilla.org.",
+        "Miscellaneous",
+    ),
 ]
 
 # Documents to append as an appendix to all manuals.

kuma/__init__.py

@@ -1,7 +1,5 @@
-
-
 # This will make sure the app is always imported when
 # Django starts so that shared_task will use this app.
 from .celery import app as celery_app
 
-__all__ = ('celery_app',)
+__all__ = ("celery_app",)

kuma/api/apps.py

@@ -6,8 +6,9 @@ class APIConfig(AppConfig):
     The Django App Config class to store information about the API app
     and do startup time things.
     """
-    name = 'kuma.api'
-    verbose_name = 'API'
+
+    name = "kuma.api"
+    verbose_name = "API"
 
     def ready(self):
         """Configure kuma.api after models are loaded."""

kuma/api/conftest.py

@@ -12,18 +12,18 @@ def redirect_to_self(wiki_user):
     """
     A top-level English document that redirects to itself.
     """
-    doc = Document.objects.create(
-        locale='en-US', slug='GoMe', title='Redirect to Self')
+    doc = Document.objects.create(locale="en-US", slug="GoMe", title="Redirect to Self")
     Revision.objects.create(
         document=doc,
         creator=wiki_user,
-        content=REDIRECT_CONTENT % {
-            'href': reverse('wiki.document', locale=doc.locale,
-                            args=(doc.slug,)),
-            'title': doc.title,
+        content=REDIRECT_CONTENT
+        % {
+            "href": reverse("wiki.document", locale=doc.locale, args=(doc.slug,)),
+            "title": doc.title,
         },
-        title='Redirect to Self',
-        created=datetime(2018, 9, 16, 11, 15))
+        title="Redirect to Self",
+        created=datetime(2018, 9, 16, 11, 15),
+    )
     return doc
 
 
@@ -33,16 +33,15 @@ def redirect_to_home(wiki_user):
     A top-level English document that redirects to the home page.
     """
     doc = Document.objects.create(
-        locale='en-US', slug='GoHome', title='Redirect to Home Page')
+        locale="en-US", slug="GoHome", title="Redirect to Home Page"
+    )
     Revision.objects.create(
         document=doc,
         creator=wiki_user,
-        content=REDIRECT_CONTENT % {
-            'href': reverse('home'),
-            'title': 'MDN Web Docs',
-        },
-        title='Redirect to Home Page',
-        created=datetime(2015, 7, 4, 11, 15))
+        content=REDIRECT_CONTENT % {"href": reverse("home"), "title": "MDN Web Docs"},
+        title="Redirect to Home Page",
+        created=datetime(2015, 7, 4, 11, 15),
+    )
     return doc
 
 
@@ -52,14 +51,17 @@ def redirect_to_macros(wiki_user):
     A top-level English document that redirects to the macros dashboard.
     """
     doc = Document.objects.create(
-        locale='en-US', slug='GoMacros', title='Redirect to Macros Dashboard')
+        locale="en-US", slug="GoMacros", title="Redirect to Macros Dashboard"
+    )
     Revision.objects.create(
         document=doc,
         creator=wiki_user,
-        content=REDIRECT_CONTENT % {
-            'href': reverse('dashboards.macros', locale='en-US'),
-            'title': 'Active macros | MDN',
+        content=REDIRECT_CONTENT
+        % {
+            "href": reverse("dashboards.macros", locale="en-US"),
+            "title": "Active macros | MDN",
         },
-        title='Redirect to Macros Dashboard',
-        created=datetime(2017, 5, 24, 12, 15))
+        title="Redirect to Macros Dashboard",
+        created=datetime(2017, 5, 24, 12, 15),
+    )
     return doc