def assert_message_fixer(old_expr, new_expr, method, is_absl=False):
"""Fixer for assertTrue()/assertFalse()/etc.
related error fixes.
assertTrue(...) often produces less readable error information than
alternative methods like assertEqual etc.
Args:
old_expr: a ExprPattern string for the expr to match
new_expr: a template string for the replacement
method: the method to link to in the docs.
is_absl: Whether this is an absl method with absl docs.
Returns:
A fixer that replaces old_expr with new_expr.
"""
if is_absl:
# absl doesn't have docs per se.
url = f'https://github.com/abseil/abseil-py/search?q=%22def+{method}%22'
else:
url = f'https://docs.python.org/3/library/unittest.html#unittest.TestCase.{method}'
dotdotdot = fixer.ImmutableDefaultDict(lambda _: '...')
return fixer.SimplePythonFixer(
message=(
'%s is a more specific assertion, and may give more detailed error information than %s.'
% (string.Template(new_expr).substitute(dotdotdot),
string.Template(old_expr).substitute(dotdotdot))),
matcher=syntax_matchers.ExprPattern(old_expr),
replacement=syntactic_template.PythonExprTemplate(new_expr),
url=url,
category='pylint.g-generic-assert',
)
def assert_alias_fixer(
old_expr,
new_expr,
url='https://docs.python.org/3/library/unittest.html#deprecated-aliases'):
"""Fixer for deprecated unittest aliases.
Args:
old_expr: A string for an ExprPattern matching the target expr.
new_expr: A string for a PythonExprTemplate to replace it with.
url: The URL documenting the deprecation.
Returns:
A fixer that replaces old_expr with new_expr.
"""
dotdotdot = fixer.ImmutableDefaultDict(lambda _: '...')
return fixer.SimplePythonFixer(
message=('{old} is a deprecated alias for {new} in the unittest module.'
.format(
old=string.Template(old_expr).substitute(dotdotdot),
new=string.Template(new_expr).substitute(dotdotdot))),
matcher=syntax_matchers.ExprPattern(old_expr),
replacement=syntactic_template.PythonExprTemplate(new_expr),
url=url,
significant=False,
category='pylint.g-deprecated-assert',
)
def idiom_fixer(
old_expr,
new_expr,
category,
url='https://refex.readthedocs.io/en/latest/guide/fixers/idiom.html',
):
"""Fixer for making expressions "clearer" / less convoluted.
This also helps normalize them for other fixers to apply.
Args:
old_expr: An ExprPattern string for the expr to match.
new_expr: A string.Template string for the replacement.
category: A category for the fix.
url: An URL describing the fix.
Returns:
A fixer that replaces old_expr with new_expr.
"""
dotdotdot = fixer.ImmutableDefaultDict(lambda _: '...')
return fixer.SimplePythonFixer(
message=('This could be more Pythonic: %s -> %s.' %
((string.Template(old_expr).substitute(dotdotdot),
string.Template(new_expr).substitute(dotdotdot)))),
matcher=syntax_matchers.ExprPattern(old_expr),
replacement=syntactic_template.PythonExprTemplate(new_expr),
url=url,
significant=False,
category=category,
)
def test_labeled_replacements_example_fragment(self):
fx = fixer.SimplePythonFixer(
message='',
matcher=syntax_matchers.ExprPattern('$y'),
replacement={'y': syntactic_template.PythonExprTemplate('$y')},
)
with self.assertRaises(TypeError):
fx.example_replacement()
def test_replace(self):
fix = fixer.SimplePythonFixer(
matcher=syntax_matchers.ExprPattern('$obj.attr'),
replacement=syntactic_template.PythonTemplate(u'$obj.other'),
)
searcher = fixer.CombiningPythonFixer([fix])
source = 'my_obj.attr + other_obj.attr'
self.assertEqual('my_obj.other + other_obj.other',
search.rewrite_string(searcher, source, 'example.py'))
def test_doesnt_discard_unparseable_compound_stmt(self):
fx = fixer.CombiningPythonFixer([
fixer.SimplePythonFixer(message='ouch',
matcher=ast_matchers.For(),
replacement=formatting.ShTemplate('x x x'),
url='')
])
self.assertEqual(
list(search.find_iter(fx, 'for x in y: pass', 'foo.py')),
[_substitution(message='ouch')])
def _mutable_constant_fixer(matcher, replacement, **kwargs):
return fixer.SimplePythonFixer(
message=
'For constants, prefer immutable collections (like frozensets or tuples) to mutable collections (like sets or lists).',
url=
'https://refex.readthedocs.io/en/latest/guide/fixers/mutable_constants.html',
significant=False,
category=_MUTABLE_CONSTANT_CATEGORY,
matcher=matcher,
replacement=replacement,
**kwargs)
def _search_replace_fixer(search_expr,
replace,
message=None,
url='',
**kwargs):
return fixer.SimplePythonFixer(
message=message if message is not None else search_expr,
matcher=syntax_matchers.ExprPattern(search_expr),
replacement=syntactic_template.PythonExprTemplate(replace),
url=url,
category='TESTONLY',
**kwargs)
def test_discards_unparseable_expr(self):
"""Searching discards unparseable substitutions for expressions.
(Note: this only happens during fixedpoint computation.)
"""
fx = fixer.CombiningPythonFixer([
fixer.SimplePythonFixer(message='',
matcher=syntax_matchers.ExprPattern('a'),
replacement=formatting.ShTemplate('x x x'),
url='')
])
self.assertEqual(
list(search.find_iter(fx, 'a', 'foo.py', max_iterations=10)), [])
def _dict_iter_fixer(method_name):
return fixer.SimplePythonFixer(
message=('dict.{method} is deprecated and does not exist in Python 3. '
'Instead, import six and use six.{method}').format(
method=method_name),
matcher=with_six(
syntax_matchers.ExprPattern('$x.{}()'.format(method_name), {
'x':
base_matchers.Unless(syntax_matchers.ExprPattern('six'))
}), ),
replacement=syntactic_template.PythonExprTemplate(
'six.{}($x)'.format(method_name)),
url='https://www.python.org/doc/sunset-python-2/',
category='pylint.dict-iter-method',
# Must define manually due to the extra restrictions on the pattern.
example_fragment='import six; x.{}()'.format(method_name),
example_replacement='import six; six.{}(x)'.format(method_name),
)
from refex.python import syntactic_template
from refex.python.matchers import ast_matchers
from refex.python.matchers import base_matchers
from refex.python.matchers import syntax_matchers
SIMPLE_PYTHON_FIXERS = [] # Disabled except when running in Python 2.
def with_six(m):
return syntax_matchers.WithTopLevelImport(m, 'six')
_HAS_KEY_FIXER = fixer.SimplePythonFixer(
message='dict.has_key() was removed in Python 3.',
matcher=syntax_matchers.ExprPattern('$a.has_key($b)'),
replacement=syntactic_template.PythonExprTemplate('$b in $a'),
url='https://docs.python.org/3.1/whatsnew/3.0.html#builtins',
significant=True,
category='refex.modernize.dict_has_key',
)
def _dict_iter_fixer(method_name):
return fixer.SimplePythonFixer(
message=('dict.{method} is deprecated and does not exist in Python 3. '
'Instead, import six and use six.{method}').format(
method=method_name),
matcher=with_six(
syntax_matchers.ExprPattern('$x.{}()'.format(method_name), {
'x':
base_matchers.Unless(syntax_matchers.ExprPattern('six'))
}), ),
fixer.SimplePythonFixer(
message=
'If a function ever returns a value, all the code paths should have a return statement with a return value.',
url=
'https://refex.readthedocs.io/en/latest/guide/fixers/return_none.html',
significant=False,
category=_NONE_RETURNS_CATEGORY,
matcher=base_matchers.AllOf(
syntax_matchers.StmtPattern('return'),
syntax_matchers.InNamedFunction(
_function_containing(_NON_NONE_RETURN)),
# Nested functions are too weird to consider right now.
# TODO: Add matchers to match only the first ancestor
# function and a way to use IsOrHasDescendant that doesn't recurse
# into nested functions.
base_matchers.Unless(
syntax_matchers.InNamedFunction(
_function_containing(
syntax_matchers.NamedFunctionDefinition())))),
replacement=syntactic_template.PythonStmtTemplate('return None'),
example_fragment=textwrap.dedent("""
def f(x):
if x:
return
return -1
"""),
example_replacement=textwrap.dedent("""
def f(x):
if x:
return None
return -1
"""),
),