Eliminate mutable default arguments

The best practice in Python is not to use mutable object (i.e. list,
dictionary, or instances of most classes) as value of default
argument (see https://goo.gl/Kwhg0T). A hacking rule to enforce this 
practice is added as well.

The patch was inspired by CR https://review.openstack.org/#/c/198465/ 
and took most of its code from it as well. That's why original 
copyrights are kept.

Closes-Bug: #1471349
Change-Id: Ia77b1736dbc3d4e28ff2d2c3424e9cfcaefa5077
This commit is contained in:
Timur Sufiev 2015-09-21 13:22:59 +03:00
parent 54495c3185
commit 7023050edd
7 changed files with 132 additions and 3 deletions

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@ -12,3 +12,4 @@ Horizon Specific Commandments
----------------------------- -----------------------------
- Read the Horizon contributing documentation at http://docs.openstack.org/developer/horizon/contributing.html - Read the Horizon contributing documentation at http://docs.openstack.org/developer/horizon/contributing.html
- [M322] Method's default argument shouldn't be mutable.

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41
horizon/hacking/checks.py Normal file
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@ -0,0 +1,41 @@
# Copyright (c) 2015 Intel, Inc.
# All Rights Reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License"); you may
# not use this file except in compliance with the License. You may obtain
# a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
# License for the specific language governing permissions and limitations
# under the License.
import re
"""
Guidelines for writing new hacking checks
- Use only for Horizon specific tests. OpenStack general tests
should be submitted to the common 'hacking' module.
- Pick numbers in the range M3xx. Find the current test with
the highest allocated number and then pick the next value.
If nova has an N3xx code for that test, use the same number.
- Keep the test method code in the source file ordered based
on the M3xx value.
- List the new rule in the top level HACKING.rst file
- Add test cases for each new rule to /tests/unit/test_hacking.py
"""
mutable_default_args = re.compile(r"^\s*def .+\((.+=\{\}|.+=\[\])")
def no_mutable_default_args(logical_line):
msg = "M322: Method's default argument shouldn't be mutable!"
if mutable_default_args.match(logical_line):
yield (0, msg)
def factory(register):
register(no_mutable_default_args)

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@ -0,0 +1,83 @@
# Copyright 2015 Intel, Inc.
#
# Licensed under the Apache License, Version 2.0 (the "License"); you may
# not use this file except in compliance with the License. You may obtain
# a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
# License for the specific language governing permissions and limitations
# under the License.
import mock
import pep8
import textwrap
from horizon.hacking import checks
from horizon.test import helpers
class HackingTestCase(helpers.TestCase):
"""This class tests the hacking checks in horizon.hacking.checks by passing
strings to the check methods like the pep8/flake8 parser would. The parser
loops over each line in the file and then passes the parameters to the
check method. The parameter names in the check method dictate what type of
object is passed to the check method. The parameter types are::
logical_line: A processed line with the following modifications:
- Multi-line statements converted to a single line.
- Stripped left and right.
- Contents of strings replaced with "xxx" of same length.
- Comments removed.
physical_line: Raw line of text from the input file.
lines: a list of the raw lines from the input file
tokens: the tokens that contribute to this logical line
line_number: line number in the input file
total_lines: number of lines in the input file
blank_lines: blank lines before this one
indent_char: indentation character in this file (" " or "\t")
indent_level: indentation (with tabs expanded to multiples of 8)
previous_indent_level: indentation on previous line
previous_logical: previous logical line
filename: Path of the file being run through pep8
When running a test on a check method the return will be False/None if
there is no violation in the sample input. If there is an error a tuple is
returned with a position in the line, and a message. So to check the result
just assertTrue if the check is expected to fail and assertFalse if it
should pass.
"""
# We are patching pep8 so that only the check under test is actually
# installed.
@mock.patch('pep8._checks',
{'physical_line': {}, 'logical_line': {}, 'tree': {}})
def _run_check(self, code, checker, filename=None):
pep8.register_check(checker)
lines = textwrap.dedent(code).strip().splitlines(True)
checker = pep8.Checker(filename=filename, lines=lines)
checker.check_all()
checker.report._deferred_print.sort()
return checker.report._deferred_print
def _assert_has_errors(self, code, checker, expected_errors=None,
filename=None):
actual_errors = [e[:3] for e in
self._run_check(code, checker, filename)]
self.assertEqual(expected_errors or [], actual_errors)
def _assert_has_no_errors(self, code, checker, filename=None):
self._assert_has_errors(code, checker, filename=filename)
def test_no_mutable_default_args(self):
self.assertEqual(1, len(list(checks.no_mutable_default_args(
"def get_info_from_bdm(virt_type, bdm, mapping=[])"))))
self.assertEqual(0, len(list(checks.no_mutable_default_args(
"defined = []"))))
self.assertEqual(0, len(list(checks.no_mutable_default_args(
"defined, undefined = [], {}"))))

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@ -242,7 +242,7 @@ def metadefs_namespace_get(request, namespace, resource_type=None, wrap=False):
def metadefs_namespace_list(request, def metadefs_namespace_list(request,
filters={}, filters=None,
sort_dir='asc', sort_dir='asc',
sort_key='namespace', sort_key='namespace',
marker=None, marker=None,
@ -275,6 +275,8 @@ def metadefs_namespace_list(request,
if get_version() < 2: if get_version() < 2:
return [], False, False return [], False, False
if filters is None:
filters = {}
limit = getattr(settings, 'API_RESULT_LIMIT', 1000) limit = getattr(settings, 'API_RESULT_LIMIT', 1000)
page_size = utils.get_page_size(request) page_size = utils.get_page_size(request)

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@ -58,7 +58,7 @@ from openstack_dashboard.test.test_data import utils as test_utils
wsgi.WSGIRequest.__repr__ = lambda self: "<class 'django.http.HttpRequest'>" wsgi.WSGIRequest.__repr__ = lambda self: "<class 'django.http.HttpRequest'>"
def create_stubs(stubs_to_create={}): def create_stubs(stubs_to_create=None):
"""decorator to simplify setting up multiple stubs at once via mox """decorator to simplify setting up multiple stubs at once via mox
:param stubs_to_create: methods to stub in one or more modules :param stubs_to_create: methods to stub in one or more modules
@ -89,7 +89,8 @@ def create_stubs(stubs_to_create={}):
} }
""" """
if stubs_to_create is None:
stubs_to_create = {}
if not isinstance(stubs_to_create, dict): if not isinstance(stubs_to_create, dict):
raise TypeError("create_stub must be passed a dict, but a %s was " raise TypeError("create_stub must be passed a dict, but a %s was "
"given." % type(stubs_to_create).__name__) "given." % type(stubs_to_create).__name__)

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@ -111,6 +111,7 @@ ignore = H405
max-complexity = 20 max-complexity = 20
[hacking] [hacking]
local-check-factory = horizon.hacking.checks.factory
import_exceptions = collections.defaultdict, import_exceptions = collections.defaultdict,
collections.OrderedDict, collections.OrderedDict,
django.conf.settings, django.conf.settings,