tools: Modify pep8.py from zulip server.

setup.py

@@ -72,6 +72,8 @@ setuptools_info = dict(
                       'typing>=3.5.2.2',
                       'flask>=0.12.2',
                       'mock>=2.0.0',
+                      # for pep8 linter
+                      'pycodestyle==2.3.1',
                       ],
 )
 

tools/pep8.py

@@ -0,0 +1,99 @@
+# This file has been copied and modified from the Zulip server repository
+# Original path: zulip/tools/linter_lib/pep8.py
+
+from __future__ import print_function
+from __future__ import absolute_import
+
+import subprocess
+import sys
+
+from server_lib.printer import print_err, colors
+
+from typing import List
+
+def check_pep8(files):
+    # type: (List[str]) -> bool
+
+    def run_pycodestyle(files, ignored_rules):
+        # type: (List[str], List[str]) -> bool
+        failed = False
+        color = next(colors)
+        pep8 = subprocess.Popen(
+            ['pycodestyle'] + files + ['--ignore={rules}'.format(rules=','.join(ignored_rules))],
+            stdout=subprocess.PIPE, stderr=subprocess.STDOUT)
+        for line in iter(pep8.stdout.readline, b''):
+            print_err('pep8', color, line)
+            failed = True
+        return failed
+
+    failed = False
+    ignored_rules = [
+        # Each of these rules are ignored for the explained reason.
+
+        # "multiple spaces before operator"
+        # There are several typos here, but also several instances that are
+        # being used for alignment in dict keys/values using the `dict`
+        # constructor. We could fix the alignment cases by switching to the `{}`
+        # constructor, but it makes fixing this rule a little less
+        # straightforward.
+        'E221',
+
+        # 'missing whitespace around arithmetic operator'
+        # This should possibly be cleaned up, though changing some of
+        # these may make the code less readable.
+        'E226',
+
+        # "unexpected spaces around keyword / parameter equals"
+        # Many of these should be fixed, but many are also being used for
+        # alignment/making the code easier to read.
+        'E251',
+
+        # "block comment should start with '#'"
+        # These serve to show which lines should be changed in files customized
+        # by the user. We could probably resolve one of E265 or E266 by
+        # standardizing on a single style for lines that the user might want to
+        # change.
+        'E265',
+
+        # "too many leading '#' for block comment"
+        # Most of these are there for valid reasons.
+        'E266',
+
+        # "expected 2 blank lines after class or function definition"
+        # Zulip only uses 1 blank line after class/function
+        # definitions; the PEP-8 recommendation results in super sparse code.
+        'E302', 'E305',
+
+        # "module level import not at top of file"
+        # Most of these are there for valid reasons, though there might be a
+        # few that could be eliminated.
+        'E402',
+
+        # "line too long"
+        # Zulip is a bit less strict about line length, and has its
+        # own check for this (see max_length)
+        'E501',
+
+        # "do not assign a lambda expression, use a def"
+        # Fixing these would probably reduce readability in most cases.
+        'E731',
+    ]
+
+    # TODO: Clear up this list of violations.
+    IGNORE_FILES_PEPE261 = []
+
+    filtered_files = [fn for fn in files if fn not in IGNORE_FILES_PEPE261]
+    filtered_files_E261 = [fn for fn in files if fn in IGNORE_FILES_PEPE261]
+
+    if len(files) == 0:
+        return False
+    if not len(filtered_files) == 0:
+        failed = run_pycodestyle(filtered_files, ignored_rules)
+    if not len(filtered_files_E261) == 0:
+        # Adding an extra ignore rule for these files since they still remain in
+        # violation of PEP-E261.
+        failed_ignore_e261 = run_pycodestyle(filtered_files_E261, ignored_rules + ['E261'])
+        if not failed:
+            failed = failed_ignore_e261
+
+    return failed