/pymode/libs/pylint/checkers/base.py
Python | 1140 lines | 1082 code | 21 blank | 37 comment | 35 complexity | 10e7797e176c640cae4b9d7124e1f292 MD5 | raw file
- # Copyright (c) 2003-2013 LOGILAB S.A. (Paris, FRANCE).
- # http://www.logilab.fr/ -- mailto:contact@logilab.fr
- # Copyright (c) 2009-2010 Arista Networks, Inc.
- #
- # This program is free software; you can redistribute it and/or modify it under
- # the terms of the GNU General Public License as published by the Free Software
- # Foundation; either version 2 of the License, or (at your option) any later
- # version.
- #
- # This program is distributed in the hope that it will be useful, but WITHOUT
- # ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
- # FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
- #
- # You should have received a copy of the GNU General Public License along with
- # this program; if not, write to the Free Software Foundation, Inc.,
- # 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
- """basic checker for Python code"""
- import collections
- import itertools
- import sys
- import re
- import six
- from six.moves import zip # pylint: disable=redefined-builtin
- from logilab.common.ureports import Table
- import astroid
- import astroid.bases
- from astroid import are_exclusive, InferenceError
- from pylint.interfaces import IAstroidChecker, INFERENCE, INFERENCE_FAILURE, HIGH
- from pylint.utils import EmptyReport
- from pylint.reporters import diff_string
- from pylint.checkers import BaseChecker
- from pylint.checkers.utils import (
- check_messages,
- clobber_in_except,
- is_builtin_object,
- is_inside_except,
- overrides_a_method,
- safe_infer,
- get_argument_from_call,
- has_known_bases,
- NoSuchArgumentError,
- is_import_error,
- unimplemented_abstract_methods,
- )
- # regex for class/function/variable/constant name
- CLASS_NAME_RGX = re.compile('[A-Z_][a-zA-Z0-9]+$')
- MOD_NAME_RGX = re.compile('(([a-z_][a-z0-9_]*)|([A-Z][a-zA-Z0-9]+))$')
- CONST_NAME_RGX = re.compile('(([A-Z_][A-Z0-9_]*)|(__.*__))$')
- COMP_VAR_RGX = re.compile('[A-Za-z_][A-Za-z0-9_]*$')
- DEFAULT_NAME_RGX = re.compile('[a-z_][a-z0-9_]{2,30}$')
- CLASS_ATTRIBUTE_RGX = re.compile(r'([A-Za-z_][A-Za-z0-9_]{2,30}|(__.*__))$')
- # do not require a doc string on system methods
- NO_REQUIRED_DOC_RGX = re.compile('__.*__')
- REVERSED_METHODS = (('__getitem__', '__len__'),
- ('__reversed__', ))
- PY33 = sys.version_info >= (3, 3)
- PY3K = sys.version_info >= (3, 0)
- BAD_FUNCTIONS = ['map', 'filter']
- if sys.version_info < (3, 0):
- BAD_FUNCTIONS.append('input')
- # Name categories that are always consistent with all naming conventions.
- EXEMPT_NAME_CATEGORIES = set(('exempt', 'ignore'))
- # A mapping from builtin-qname -> symbol, to be used when generating messages
- # about dangerous default values as arguments
- DEFAULT_ARGUMENT_SYMBOLS = dict(
- zip(['.'.join([astroid.bases.BUILTINS, x]) for x in ('set', 'dict', 'list')],
- ['set()', '{}', '[]'])
- )
- del re
- def _redefines_import(node):
- """ Detect that the given node (AssName) is inside an
- exception handler and redefines an import from the tryexcept body.
- Returns True if the node redefines an import, False otherwise.
- """
- current = node
- while current and not isinstance(current.parent, astroid.ExceptHandler):
- current = current.parent
- if not current or not is_import_error(current.parent):
- return False
- try_block = current.parent.parent
- for import_node in try_block.nodes_of_class((astroid.From, astroid.Import)):
- for name, alias in import_node.names:
- if alias:
- if alias == node.name:
- return True
- elif name == node.name:
- return True
- return False
- def in_loop(node):
- """return True if the node is inside a kind of for loop"""
- parent = node.parent
- while parent is not None:
- if isinstance(parent, (astroid.For, astroid.ListComp, astroid.SetComp,
- astroid.DictComp, astroid.GenExpr)):
- return True
- parent = parent.parent
- return False
- def in_nested_list(nested_list, obj):
- """return true if the object is an element of <nested_list> or of a nested
- list
- """
- for elmt in nested_list:
- if isinstance(elmt, (list, tuple)):
- if in_nested_list(elmt, obj):
- return True
- elif elmt == obj:
- return True
- return False
- def _loop_exits_early(loop):
- """Returns true if a loop has a break statement in its body."""
- loop_nodes = (astroid.For, astroid.While)
- # Loop over body explicitly to avoid matching break statements
- # in orelse.
- for child in loop.body:
- if isinstance(child, loop_nodes):
- # break statement may be in orelse of child loop.
- # pylint: disable=superfluous-parens
- for orelse in (child.orelse or ()):
- for _ in orelse.nodes_of_class(astroid.Break, skip_klass=loop_nodes):
- return True
- continue
- for _ in child.nodes_of_class(astroid.Break, skip_klass=loop_nodes):
- return True
- return False
- def _is_multi_naming_match(match, node_type, confidence):
- return (match is not None and
- match.lastgroup is not None and
- match.lastgroup not in EXEMPT_NAME_CATEGORIES
- and (node_type != 'method' or confidence != INFERENCE_FAILURE))
- if sys.version_info < (3, 0):
- PROPERTY_CLASSES = set(('__builtin__.property', 'abc.abstractproperty'))
- else:
- PROPERTY_CLASSES = set(('builtins.property', 'abc.abstractproperty'))
- def _determine_function_name_type(node):
- """Determine the name type whose regex the a function's name should match.
- :param node: A function node.
- :returns: One of ('function', 'method', 'attr')
- """
- if not node.is_method():
- return 'function'
- if node.decorators:
- decorators = node.decorators.nodes
- else:
- decorators = []
- for decorator in decorators:
- # If the function is a property (decorated with @property
- # or @abc.abstractproperty), the name type is 'attr'.
- if (isinstance(decorator, astroid.Name) or
- (isinstance(decorator, astroid.Getattr) and
- decorator.attrname == 'abstractproperty')):
- infered = safe_infer(decorator)
- if infered and infered.qname() in PROPERTY_CLASSES:
- return 'attr'
- # If the function is decorated using the prop_method.{setter,getter}
- # form, treat it like an attribute as well.
- elif (isinstance(decorator, astroid.Getattr) and
- decorator.attrname in ('setter', 'deleter')):
- return 'attr'
- return 'method'
- def _has_abstract_methods(node):
- """
- Determine if the given `node` has abstract methods.
- The methods should be made abstract by decorating them
- with `abc` decorators.
- """
- return len(unimplemented_abstract_methods(node)) > 0
- def report_by_type_stats(sect, stats, old_stats):
- """make a report of
- * percentage of different types documented
- * percentage of different types with a bad name
- """
- # percentage of different types documented and/or with a bad name
- nice_stats = {}
- for node_type in ('module', 'class', 'method', 'function'):
- try:
- total = stats[node_type]
- except KeyError:
- raise EmptyReport()
- nice_stats[node_type] = {}
- if total != 0:
- try:
- documented = total - stats['undocumented_'+node_type]
- percent = (documented * 100.) / total
- nice_stats[node_type]['percent_documented'] = '%.2f' % percent
- except KeyError:
- nice_stats[node_type]['percent_documented'] = 'NC'
- try:
- percent = (stats['badname_'+node_type] * 100.) / total
- nice_stats[node_type]['percent_badname'] = '%.2f' % percent
- except KeyError:
- nice_stats[node_type]['percent_badname'] = 'NC'
- lines = ('type', 'number', 'old number', 'difference',
- '%documented', '%badname')
- for node_type in ('module', 'class', 'method', 'function'):
- new = stats[node_type]
- old = old_stats.get(node_type, None)
- if old is not None:
- diff_str = diff_string(old, new)
- else:
- old, diff_str = 'NC', 'NC'
- lines += (node_type, str(new), str(old), diff_str,
- nice_stats[node_type].get('percent_documented', '0'),
- nice_stats[node_type].get('percent_badname', '0'))
- sect.append(Table(children=lines, cols=6, rheaders=1))
- def redefined_by_decorator(node):
- """return True if the object is a method redefined via decorator.
- For example:
- @property
- def x(self): return self._x
- @x.setter
- def x(self, value): self._x = value
- """
- if node.decorators:
- for decorator in node.decorators.nodes:
- if (isinstance(decorator, astroid.Getattr) and
- getattr(decorator.expr, 'name', None) == node.name):
- return True
- return False
- class _BasicChecker(BaseChecker):
- __implements__ = IAstroidChecker
- name = 'basic'
- class BasicErrorChecker(_BasicChecker):
- msgs = {
- 'E0100': ('__init__ method is a generator',
- 'init-is-generator',
- 'Used when the special class method __init__ is turned into a '
- 'generator by a yield in its body.'),
- 'E0101': ('Explicit return in __init__',
- 'return-in-init',
- 'Used when the special class method __init__ has an explicit '
- 'return value.'),
- 'E0102': ('%s already defined line %s',
- 'function-redefined',
- 'Used when a function / class / method is redefined.'),
- 'E0103': ('%r not properly in loop',
- 'not-in-loop',
- 'Used when break or continue keywords are used outside a loop.'),
- 'E0104': ('Return outside function',
- 'return-outside-function',
- 'Used when a "return" statement is found outside a function or '
- 'method.'),
- 'E0105': ('Yield outside function',
- 'yield-outside-function',
- 'Used when a "yield" statement is found outside a function or '
- 'method.'),
- 'E0106': ('Return with argument inside generator',
- 'return-arg-in-generator',
- 'Used when a "return" statement with an argument is found '
- 'outside in a generator function or method (e.g. with some '
- '"yield" statements).',
- {'maxversion': (3, 3)}),
- 'E0107': ("Use of the non-existent %s operator",
- 'nonexistent-operator',
- "Used when you attempt to use the C-style pre-increment or"
- "pre-decrement operator -- and ++, which doesn't exist in Python."),
- 'E0108': ('Duplicate argument name %s in function definition',
- 'duplicate-argument-name',
- 'Duplicate argument names in function definitions are syntax'
- ' errors.'),
- 'E0110': ('Abstract class %r with abstract methods instantiated',
- 'abstract-class-instantiated',
- 'Used when an abstract class with `abc.ABCMeta` as metaclass '
- 'has abstract methods and is instantiated.'),
- 'W0120': ('Else clause on loop without a break statement',
- 'useless-else-on-loop',
- 'Loops should only have an else clause if they can exit early '
- 'with a break statement, otherwise the statements under else '
- 'should be on the same scope as the loop itself.'),
- }
- @check_messages('function-redefined')
- def visit_class(self, node):
- self._check_redefinition('class', node)
- @check_messages('init-is-generator', 'return-in-init',
- 'function-redefined', 'return-arg-in-generator',
- 'duplicate-argument-name')
- def visit_function(self, node):
- if not redefined_by_decorator(node):
- self._check_redefinition(node.is_method() and 'method' or 'function', node)
- # checks for max returns, branch, return in __init__
- returns = node.nodes_of_class(astroid.Return,
- skip_klass=(astroid.Function, astroid.Class))
- if node.is_method() and node.name == '__init__':
- if node.is_generator():
- self.add_message('init-is-generator', node=node)
- else:
- values = [r.value for r in returns]
- # Are we returning anything but None from constructors
- if [v for v in values
- if not (v is None or
- (isinstance(v, astroid.Const) and v.value is None) or
- (isinstance(v, astroid.Name) and v.name == 'None')
- )]:
- self.add_message('return-in-init', node=node)
- elif node.is_generator():
- # make sure we don't mix non-None returns and yields
- if not PY33:
- for retnode in returns:
- if isinstance(retnode.value, astroid.Const) and \
- retnode.value.value is not None:
- self.add_message('return-arg-in-generator', node=node,
- line=retnode.fromlineno)
- # Check for duplicate names
- args = set()
- for name in node.argnames():
- if name in args:
- self.add_message('duplicate-argument-name', node=node, args=(name,))
- else:
- args.add(name)
- @check_messages('return-outside-function')
- def visit_return(self, node):
- if not isinstance(node.frame(), astroid.Function):
- self.add_message('return-outside-function', node=node)
- @check_messages('yield-outside-function')
- def visit_yield(self, node):
- if not isinstance(node.frame(), (astroid.Function, astroid.Lambda)):
- self.add_message('yield-outside-function', node=node)
- @check_messages('not-in-loop')
- def visit_continue(self, node):
- self._check_in_loop(node, 'continue')
- @check_messages('not-in-loop')
- def visit_break(self, node):
- self._check_in_loop(node, 'break')
- @check_messages('useless-else-on-loop')
- def visit_for(self, node):
- self._check_else_on_loop(node)
- @check_messages('useless-else-on-loop')
- def visit_while(self, node):
- self._check_else_on_loop(node)
- @check_messages('nonexistent-operator')
- def visit_unaryop(self, node):
- """check use of the non-existent ++ and -- operator operator"""
- if ((node.op in '+-') and
- isinstance(node.operand, astroid.UnaryOp) and
- (node.operand.op == node.op)):
- self.add_message('nonexistent-operator', node=node, args=node.op*2)
- @check_messages('abstract-class-instantiated')
- def visit_callfunc(self, node):
- """ Check instantiating abstract class with
- abc.ABCMeta as metaclass.
- """
- try:
- infered = next(node.func.infer())
- except astroid.InferenceError:
- return
- if not isinstance(infered, astroid.Class):
- return
- # __init__ was called
- metaclass = infered.metaclass()
- abstract_methods = _has_abstract_methods(infered)
- if metaclass is None:
- # Python 3.4 has `abc.ABC`, which won't be detected
- # by ClassNode.metaclass()
- for ancestor in infered.ancestors():
- if ancestor.qname() == 'abc.ABC' and abstract_methods:
- self.add_message('abstract-class-instantiated',
- args=(infered.name, ),
- node=node)
- break
- return
- if metaclass.qname() == 'abc.ABCMeta' and abstract_methods:
- self.add_message('abstract-class-instantiated',
- args=(infered.name, ),
- node=node)
- def _check_else_on_loop(self, node):
- """Check that any loop with an else clause has a break statement."""
- if node.orelse and not _loop_exits_early(node):
- self.add_message('useless-else-on-loop', node=node,
- # This is not optimal, but the line previous
- # to the first statement in the else clause
- # will usually be the one that contains the else:.
- line=node.orelse[0].lineno - 1)
- def _check_in_loop(self, node, node_name):
- """check that a node is inside a for or while loop"""
- _node = node.parent
- while _node:
- if isinstance(_node, (astroid.For, astroid.While)):
- break
- _node = _node.parent
- else:
- self.add_message('not-in-loop', node=node, args=node_name)
- def _check_redefinition(self, redeftype, node):
- """check for redefinition of a function / method / class name"""
- defined_self = node.parent.frame()[node.name]
- if defined_self is not node and not are_exclusive(node, defined_self):
- self.add_message('function-redefined', node=node,
- args=(redeftype, defined_self.fromlineno))
- class BasicChecker(_BasicChecker):
- """checks for :
- * doc strings
- * number of arguments, local variables, branches, returns and statements in
- functions, methods
- * required module attributes
- * dangerous default values as arguments
- * redefinition of function / method / class
- * uses of the global statement
- """
- __implements__ = IAstroidChecker
- name = 'basic'
- msgs = {
- 'W0101': ('Unreachable code',
- 'unreachable',
- 'Used when there is some code behind a "return" or "raise" '
- 'statement, which will never be accessed.'),
- 'W0102': ('Dangerous default value %s as argument',
- 'dangerous-default-value',
- 'Used when a mutable value as list or dictionary is detected in '
- 'a default value for an argument.'),
- 'W0104': ('Statement seems to have no effect',
- 'pointless-statement',
- 'Used when a statement doesn\'t have (or at least seems to) '
- 'any effect.'),
- 'W0105': ('String statement has no effect',
- 'pointless-string-statement',
- 'Used when a string is used as a statement (which of course '
- 'has no effect). This is a particular case of W0104 with its '
- 'own message so you can easily disable it if you\'re using '
- 'those strings as documentation, instead of comments.'),
- 'W0106': ('Expression "%s" is assigned to nothing',
- 'expression-not-assigned',
- 'Used when an expression that is not a function call is assigned '
- 'to nothing. Probably something else was intended.'),
- 'W0108': ('Lambda may not be necessary',
- 'unnecessary-lambda',
- 'Used when the body of a lambda expression is a function call '
- 'on the same argument list as the lambda itself; such lambda '
- 'expressions are in all but a few cases replaceable with the '
- 'function being called in the body of the lambda.'),
- 'W0109': ("Duplicate key %r in dictionary",
- 'duplicate-key',
- 'Used when a dictionary expression binds the same key multiple '
- 'times.'),
- 'W0122': ('Use of exec',
- 'exec-used',
- 'Used when you use the "exec" statement (function for Python '
- '3), to discourage its usage. That doesn\'t '
- 'mean you can not use it !'),
- 'W0123': ('Use of eval',
- 'eval-used',
- 'Used when you use the "eval" function, to discourage its '
- 'usage. Consider using `ast.literal_eval` for safely evaluating '
- 'strings containing Python expressions '
- 'from untrusted sources. '),
- 'W0141': ('Used builtin function %r',
- 'bad-builtin',
- 'Used when a black listed builtin function is used (see the '
- 'bad-function option). Usual black listed functions are the ones '
- 'like map, or filter , where Python offers now some cleaner '
- 'alternative like list comprehension.'),
- 'W0150': ("%s statement in finally block may swallow exception",
- 'lost-exception',
- 'Used when a break or a return statement is found inside the '
- 'finally clause of a try...finally block: the exceptions raised '
- 'in the try clause will be silently swallowed instead of being '
- 're-raised.'),
- 'W0199': ('Assert called on a 2-uple. Did you mean \'assert x,y\'?',
- 'assert-on-tuple',
- 'A call of assert on a tuple will always evaluate to true if '
- 'the tuple is not empty, and will always evaluate to false if '
- 'it is.'),
- 'C0121': ('Missing required attribute "%s"', # W0103
- 'missing-module-attribute',
- 'Used when an attribute required for modules is missing.'),
- 'E0109': ('Missing argument to reversed()',
- 'missing-reversed-argument',
- 'Used when reversed() builtin didn\'t receive an argument.'),
- 'E0111': ('The first reversed() argument is not a sequence',
- 'bad-reversed-sequence',
- 'Used when the first argument to reversed() builtin '
- 'isn\'t a sequence (does not implement __reversed__, '
- 'nor __getitem__ and __len__'),
- }
- options = (('required-attributes',
- {'default' : (), 'type' : 'csv',
- 'metavar' : '<attributes>',
- 'help' : 'Required attributes for module, separated by a '
- 'comma'}
- ),
- ('bad-functions',
- {'default' : BAD_FUNCTIONS,
- 'type' :'csv', 'metavar' : '<builtin function names>',
- 'help' : 'List of builtins function names that should not be '
- 'used, separated by a comma'}
- ),
- )
- reports = (('RP0101', 'Statistics by type', report_by_type_stats),)
- def __init__(self, linter):
- _BasicChecker.__init__(self, linter)
- self.stats = None
- self._tryfinallys = None
- def open(self):
- """initialize visit variables and statistics
- """
- self._tryfinallys = []
- self.stats = self.linter.add_stats(module=0, function=0,
- method=0, class_=0)
- @check_messages('missing-module-attribute')
- def visit_module(self, node):
- """check module name, docstring and required arguments
- """
- self.stats['module'] += 1
- for attr in self.config.required_attributes:
- if attr not in node:
- self.add_message('missing-module-attribute', node=node, args=attr)
- def visit_class(self, node): # pylint: disable=unused-argument
- """check module name, docstring and redefinition
- increment branch counter
- """
- self.stats['class'] += 1
- @check_messages('pointless-statement', 'pointless-string-statement',
- 'expression-not-assigned')
- def visit_discard(self, node):
- """check for various kind of statements without effect"""
- expr = node.value
- if isinstance(expr, astroid.Const) and isinstance(expr.value,
- six.string_types):
- # treat string statement in a separated message
- # Handle PEP-257 attribute docstrings.
- # An attribute docstring is defined as being a string right after
- # an assignment at the module level, class level or __init__ level.
- scope = expr.scope()
- if isinstance(scope, (astroid.Class, astroid.Module, astroid.Function)):
- if isinstance(scope, astroid.Function) and scope.name != '__init__':
- pass
- else:
- sibling = expr.previous_sibling()
- if (sibling is not None and sibling.scope() is scope and
- isinstance(sibling, astroid.Assign)):
- return
- self.add_message('pointless-string-statement', node=node)
- return
- # ignore if this is :
- # * a direct function call
- # * the unique child of a try/except body
- # * a yield (which are wrapped by a discard node in _ast XXX)
- # warn W0106 if we have any underlying function call (we can't predict
- # side effects), else pointless-statement
- if (isinstance(expr, (astroid.Yield, astroid.CallFunc)) or
- (isinstance(node.parent, astroid.TryExcept) and
- node.parent.body == [node])):
- return
- if any(expr.nodes_of_class(astroid.CallFunc)):
- self.add_message('expression-not-assigned', node=node,
- args=expr.as_string())
- else:
- self.add_message('pointless-statement', node=node)
- @check_messages('unnecessary-lambda')
- def visit_lambda(self, node):
- """check whether or not the lambda is suspicious
- """
- # if the body of the lambda is a call expression with the same
- # argument list as the lambda itself, then the lambda is
- # possibly unnecessary and at least suspicious.
- if node.args.defaults:
- # If the arguments of the lambda include defaults, then a
- # judgment cannot be made because there is no way to check
- # that the defaults defined by the lambda are the same as
- # the defaults defined by the function called in the body
- # of the lambda.
- return
- call = node.body
- if not isinstance(call, astroid.CallFunc):
- # The body of the lambda must be a function call expression
- # for the lambda to be unnecessary.
- return
- # XXX are lambda still different with astroid >= 0.18 ?
- # *args and **kwargs need to be treated specially, since they
- # are structured differently between the lambda and the function
- # call (in the lambda they appear in the args.args list and are
- # indicated as * and ** by two bits in the lambda's flags, but
- # in the function call they are omitted from the args list and
- # are indicated by separate attributes on the function call node).
- ordinary_args = list(node.args.args)
- if node.args.kwarg:
- if (not call.kwargs
- or not isinstance(call.kwargs, astroid.Name)
- or node.args.kwarg != call.kwargs.name):
- return
- elif call.kwargs:
- return
- if node.args.vararg:
- if (not call.starargs
- or not isinstance(call.starargs, astroid.Name)
- or node.args.vararg != call.starargs.name):
- return
- elif call.starargs:
- return
- # The "ordinary" arguments must be in a correspondence such that:
- # ordinary_args[i].name == call.args[i].name.
- if len(ordinary_args) != len(call.args):
- return
- for i in range(len(ordinary_args)):
- if not isinstance(call.args[i], astroid.Name):
- return
- if node.args.args[i].name != call.args[i].name:
- return
- if (isinstance(node.body.func, astroid.Getattr) and
- isinstance(node.body.func.expr, astroid.CallFunc)):
- # Chained call, the intermediate call might
- # return something else (but we don't check that, yet).
- return
- self.add_message('unnecessary-lambda', line=node.fromlineno, node=node)
- @check_messages('dangerous-default-value')
- def visit_function(self, node):
- """check function name, docstring, arguments, redefinition,
- variable names, max locals
- """
- self.stats[node.is_method() and 'method' or 'function'] += 1
- self._check_dangerous_default(node)
- def _check_dangerous_default(self, node):
- # check for dangerous default values as arguments
- is_iterable = lambda n: isinstance(n, (astroid.List,
- astroid.Set,
- astroid.Dict))
- for default in node.args.defaults:
- try:
- value = next(default.infer())
- except astroid.InferenceError:
- continue
- if (isinstance(value, astroid.Instance) and
- value.qname() in DEFAULT_ARGUMENT_SYMBOLS):
- if value is default:
- msg = DEFAULT_ARGUMENT_SYMBOLS[value.qname()]
- elif type(value) is astroid.Instance or is_iterable(value):
- # We are here in the following situation(s):
- # * a dict/set/list/tuple call which wasn't inferred
- # to a syntax node ({}, () etc.). This can happen
- # when the arguments are invalid or unknown to
- # the inference.
- # * a variable from somewhere else, which turns out to be a list
- # or a dict.
- if is_iterable(default):
- msg = value.pytype()
- elif isinstance(default, astroid.CallFunc):
- msg = '%s() (%s)' % (value.name, value.qname())
- else:
- msg = '%s (%s)' % (default.as_string(), value.qname())
- else:
- # this argument is a name
- msg = '%s (%s)' % (default.as_string(),
- DEFAULT_ARGUMENT_SYMBOLS[value.qname()])
- self.add_message('dangerous-default-value',
- node=node,
- args=(msg, ))
- @check_messages('unreachable', 'lost-exception')
- def visit_return(self, node):
- """1 - check is the node has a right sibling (if so, that's some
- unreachable code)
- 2 - check is the node is inside the finally clause of a try...finally
- block
- """
- self._check_unreachable(node)
- # Is it inside final body of a try...finally bloc ?
- self._check_not_in_finally(node, 'return', (astroid.Function,))
- @check_messages('unreachable')
- def visit_continue(self, node):
- """check is the node has a right sibling (if so, that's some unreachable
- code)
- """
- self._check_unreachable(node)
- @check_messages('unreachable', 'lost-exception')
- def visit_break(self, node):
- """1 - check is the node has a right sibling (if so, that's some
- unreachable code)
- 2 - check is the node is inside the finally clause of a try...finally
- block
- """
- # 1 - Is it right sibling ?
- self._check_unreachable(node)
- # 2 - Is it inside final body of a try...finally bloc ?
- self._check_not_in_finally(node, 'break', (astroid.For, astroid.While,))
- @check_messages('unreachable')
- def visit_raise(self, node):
- """check if the node has a right sibling (if so, that's some unreachable
- code)
- """
- self._check_unreachable(node)
- @check_messages('exec-used')
- def visit_exec(self, node):
- """just print a warning on exec statements"""
- self.add_message('exec-used', node=node)
- @check_messages('bad-builtin', 'eval-used',
- 'exec-used', 'missing-reversed-argument',
- 'bad-reversed-sequence')
- def visit_callfunc(self, node):
- """visit a CallFunc node -> check if this is not a blacklisted builtin
- call and check for * or ** use
- """
- if isinstance(node.func, astroid.Name):
- name = node.func.name
- # ignore the name if it's not a builtin (i.e. not defined in the
- # locals nor globals scope)
- if not (name in node.frame() or
- name in node.root()):
- if name == 'exec':
- self.add_message('exec-used', node=node)
- elif name == 'reversed':
- self._check_reversed(node)
- elif name == 'eval':
- self.add_message('eval-used', node=node)
- if name in self.config.bad_functions:
- self.add_message('bad-builtin', node=node, args=name)
- @check_messages('assert-on-tuple')
- def visit_assert(self, node):
- """check the use of an assert statement on a tuple."""
- if node.fail is None and isinstance(node.test, astroid.Tuple) and \
- len(node.test.elts) == 2:
- self.add_message('assert-on-tuple', node=node)
- @check_messages('duplicate-key')
- def visit_dict(self, node):
- """check duplicate key in dictionary"""
- keys = set()
- for k, _ in node.items:
- if isinstance(k, astroid.Const):
- key = k.value
- if key in keys:
- self.add_message('duplicate-key', node=node, args=key)
- keys.add(key)
- def visit_tryfinally(self, node):
- """update try...finally flag"""
- self._tryfinallys.append(node)
- def leave_tryfinally(self, node): # pylint: disable=unused-argument
- """update try...finally flag"""
- self._tryfinallys.pop()
- def _check_unreachable(self, node):
- """check unreachable code"""
- unreach_stmt = node.next_sibling()
- if unreach_stmt is not None:
- self.add_message('unreachable', node=unreach_stmt)
- def _check_not_in_finally(self, node, node_name, breaker_classes=()):
- """check that a node is not inside a finally clause of a
- try...finally statement.
- If we found before a try...finally bloc a parent which its type is
- in breaker_classes, we skip the whole check."""
- # if self._tryfinallys is empty, we're not a in try...finally bloc
- if not self._tryfinallys:
- return
- # the node could be a grand-grand...-children of the try...finally
- _parent = node.parent
- _node = node
- while _parent and not isinstance(_parent, breaker_classes):
- if hasattr(_parent, 'finalbody') and _node in _parent.finalbody:
- self.add_message('lost-exception', node=node, args=node_name)
- return
- _node = _parent
- _parent = _node.parent
- def _check_reversed(self, node):
- """ check that the argument to `reversed` is a sequence """
- try:
- argument = safe_infer(get_argument_from_call(node, position=0))
- except NoSuchArgumentError:
- self.add_message('missing-reversed-argument', node=node)
- else:
- if argument is astroid.YES:
- return
- if argument is None:
- # Nothing was infered.
- # Try to see if we have iter().
- if isinstance(node.args[0], astroid.CallFunc):
- try:
- func = next(node.args[0].func.infer())
- except InferenceError:
- return
- if (getattr(func, 'name', None) == 'iter' and
- is_builtin_object(func)):
- self.add_message('bad-reversed-sequence', node=node)
- return
- if isinstance(argument, astroid.Instance):
- if (argument._proxied.name == 'dict' and
- is_builtin_object(argument._proxied)):
- self.add_message('bad-reversed-sequence', node=node)
- return
- elif any(ancestor.name == 'dict' and is_builtin_object(ancestor)
- for ancestor in argument._proxied.ancestors()):
- # mappings aren't accepted by reversed()
- self.add_message('bad-reversed-sequence', node=node)
- return
- for methods in REVERSED_METHODS:
- for meth in methods:
- try:
- argument.getattr(meth)
- except astroid.NotFoundError:
- break
- else:
- break
- else:
- # Check if it is a .deque. It doesn't seem that
- # we can retrieve special methods
- # from C implemented constructs.
- if argument._proxied.qname().endswith(".deque"):
- return
- self.add_message('bad-reversed-sequence', node=node)
- elif not isinstance(argument, (astroid.List, astroid.Tuple)):
- # everything else is not a proper sequence for reversed()
- self.add_message('bad-reversed-sequence', node=node)
- _NAME_TYPES = {
- 'module': (MOD_NAME_RGX, 'module'),
- 'const': (CONST_NAME_RGX, 'constant'),
- 'class': (CLASS_NAME_RGX, 'class'),
- 'function': (DEFAULT_NAME_RGX, 'function'),
- 'method': (DEFAULT_NAME_RGX, 'method'),
- 'attr': (DEFAULT_NAME_RGX, 'attribute'),
- 'argument': (DEFAULT_NAME_RGX, 'argument'),
- 'variable': (DEFAULT_NAME_RGX, 'variable'),
- 'class_attribute': (CLASS_ATTRIBUTE_RGX, 'class attribute'),
- 'inlinevar': (COMP_VAR_RGX, 'inline iteration'),
- }
- def _create_naming_options():
- name_options = []
- for name_type, (rgx, human_readable_name) in six.iteritems(_NAME_TYPES):
- name_type = name_type.replace('_', '-')
- name_options.append((
- '%s-rgx' % (name_type,),
- {'default': rgx, 'type': 'regexp', 'metavar': '<regexp>',
- 'help': 'Regular expression matching correct %s names' % (human_readable_name,)}))
- name_options.append((
- '%s-name-hint' % (name_type,),
- {'default': rgx.pattern, 'type': 'string', 'metavar': '<string>',
- 'help': 'Naming hint for %s names' % (human_readable_name,)}))
- return tuple(name_options)
- class NameChecker(_BasicChecker):
- msgs = {
- 'C0102': ('Black listed name "%s"',
- 'blacklisted-name',
- 'Used when the name is listed in the black list (unauthorized '
- 'names).'),
- 'C0103': ('Invalid %s name "%s"%s',
- 'invalid-name',
- 'Used when the name doesn\'t match the regular expression '
- 'associated to its type (constant, variable, class...).'),
- }
- options = (('good-names',
- {'default' : ('i', 'j', 'k', 'ex', 'Run', '_'),
- 'type' :'csv', 'metavar' : '<names>',
- 'help' : 'Good variable names which should always be accepted,'
- ' separated by a comma'}
- ),
- ('bad-names',
- {'default' : ('foo', 'bar', 'baz', 'toto', 'tutu', 'tata'),
- 'type' :'csv', 'metavar' : '<names>',
- 'help' : 'Bad variable names which should always be refused, '
- 'separated by a comma'}
- ),
- ('name-group',
- {'default' : (),
- 'type' :'csv', 'metavar' : '<name1:name2>',
- 'help' : ('Colon-delimited sets of names that determine each'
- ' other\'s naming style when the name regexes'
- ' allow several styles.')}
- ),
- ('include-naming-hint',
- {'default': False, 'type' : 'yn', 'metavar' : '<y_or_n>',
- 'help': 'Include a hint for the correct naming format with invalid-name'}
- ),
- ) + _create_naming_options()
- def __init__(self, linter):
- _BasicChecker.__init__(self, linter)
- self._name_category = {}
- self._name_group = {}
- self._bad_names = {}
- def open(self):
- self.stats = self.linter.add_stats(badname_module=0,
- badname_class=0, badname_function=0,
- badname_method=0, badname_attr=0,
- badname_const=0,
- badname_variable=0,
- badname_inlinevar=0,
- badname_argument=0,
- badname_class_attribute=0)
- for group in self.config.name_group:
- for name_type in group.split(':'):
- self._name_group[name_type] = 'group_%s' % (group,)
- @check_messages('blacklisted-name', 'invalid-name')
- def visit_module(self, node):
- self._check_name('module', node.name.split('.')[-1], node)
- self._bad_names = {}
- def leave_module(self, node): # pylint: disable=unused-argument
- for all_groups in six.itervalues(self._bad_names):
- if len(all_groups) < 2:
- continue
- groups = collections.defaultdict(list)
- min_warnings = sys.maxsize
- for group in six.itervalues(all_groups):
- groups[len(group)].append(group)
- min_warnings = min(len(group), min_warnings)
- if len(groups[min_warnings]) > 1:
- by_line = sorted(groups[min_warnings],
- key=lambda group: min(warning[0].lineno for warning in group))
- warnings = itertools.chain(*by_line[1:])
- else:
- warnings = groups[min_warnings][0]
- for args in warnings:
- self._raise_name_warning(*args)
- @check_messages('blacklisted-name', 'invalid-name')
- def visit_class(self, node):
- self._check_name('class', node.name, node)
- for attr, anodes in six.iteritems(node.instance_attrs):
- if not list(node.instance_attr_ancestors(attr)):
- self._check_name('attr', attr, anodes[0])
- @check_messages('blacklisted-name', 'invalid-name')
- def visit_function(self, node):
- # Do not emit any warnings if the method is just an implementation
- # of a base class method.
- confidence = HIGH
- if node.is_method():
- if overrides_a_method(node.parent.frame(), node.name):
- return
- confidence = (INFERENCE if has_known_bases(node.parent.frame())
- else INFERENCE_FAILURE)
- self._check_name(_determine_function_name_type(node),
- node.name, node, confidence)
- # Check argument names
- args = node.args.args
- if args is not None:
- self._recursive_check_names(args, node)
- @check_messages('blacklisted-name', 'invalid-name')
- def visit_global(self, node):
- for name in node.names:
- self._check_name('const', name, node)
- @check_messages('blacklisted-name', 'invalid-name')
- def visit_assname(self, node):
- """check module level assigned names"""
- frame = node.frame()
- ass_type = node.ass_type()
- if isinstance(ass_type, astroid.Comprehension):
- self._check_name('inlinevar', node.name, node)
- elif isinstance(frame, astroid.Module):
- if isinstance(ass_type, astroid.Assign) and not in_loop(ass_type):
- if isinstance(safe_infer(ass_type.value), astroid.Class):
- self._check_name('class', node.name, node)
- else:
- if not _redefines_import(node):
- # Don't emit if the name redefines an import
- # in an ImportError except handler.
- self._check_name('const', node.name, node)
- elif isinstance(ass_type, astroid.ExceptHandler):
- self._check_name('variable', node.name, node)
- elif isinstance(frame, astroid.Function):
- # global introduced variable aren't in the function locals
- if node.name in frame and node.name not in frame.argnames():
- if not _redefines_import(node):
- self._check_name('variable', node.name, node)
- elif isinstance(frame, astroid.Class):
- if not list(frame.local_attr_ancestors(node.name)):
- self._check_name('class_attribute', node.name, node)
- def _recursive_check_names(self, args, node):
- """check names in a possibly recursive list <arg>"""
- for arg in args:
- if isinstance(arg, astroid.AssName):
- self._check_name('argument', arg.name, node)
- else:
- self._recursive_check_names(arg.elts, node)
- def _find_name_group(self, node_type):
- return self._name_group.get(node_type, node_type)
- def _raise_name_warning(self, node, node_type, name, confidence):
- type_label = _NAME_TYPES[node_type][1]
- hint = ''
- if self.config.include_naming_hint:
- hint = ' (hint: %s)' % (getattr(self.config, node_type + '_name_hint'))
- self.add_message('invalid-name', node=node, args=(type_label, name, hint),
- confidence=confidence)
- self.stats['badname_' + node_type] += 1
- def _check_name(self, node_type, name, node, confidence=HIGH):
- """check for a name using the type's regexp"""
- if is_inside_except(node):
- clobbering, _ = clobber_in_except(node)
- if clobbering:
- return
- if name in self.config.good_names:
- return
- if name in self.config.bad_names:
- self.stats['badname_' + node_type] += 1
- self.add_message('blacklisted-name', node=node, args=name)
- return
- regexp = getattr(self.config, node_type + '_rgx')
- match = regexp.match(name)
- if _is_multi_naming_match(match, node_type, confidence):
- name_group = self._find_name_group(node_type)
- bad_name_group = self._bad_names.setdefault(name_group, {})
- warnings = bad_name_group.setdefault(match.lastgroup, [])
- warnings.append((node, node_type, name, confidence))
- if match is None:
- self._raise_name_warning(node, node_type, name, confidence)
- class DocStringChecker(_BasicChecker):
- msgs = {
- 'C0111': ('Missing %s docstring', # W0131
- 'missing-docstring',
- 'Used when a module, function, class or method has no docstring.'
- 'Some special methods like __init__ doesn\'t necessary require a '
- 'docstring.'),
- 'C0112': ('Empty %s docstring', # W0132
- 'empty-docstring',
- 'Used when a module, function, class or method has an empty '
- 'docstring (it would be too easy ;).'),
- }
- options = (('no-docstring-rgx',
- {'default' : NO_REQUIRED_DOC_RGX,
- 'type' : 'regexp', 'metavar' : '<regexp>',
- 'help' : 'Regular expression which should only match '
- 'function or class names that do not require a '
- 'docstring.'}
- ),
- ('docstring-min-length',
- {'default' : -1,
- 'type' : 'int', 'metavar' : '<int>',
- 'help': ('Minimum line length for functions/classes that'
- ' require docstrings, shorter ones are exempt.')}
- ),
- )
- def open(self):
- self.stats = self.linter.add_stats(undocumented_module=0,
- undocumented_function=0,
- undocumented_method=0,
- undocumented_class=0)
- @check_messages('missing-docstring', 'empty-docstring')
- def visit_module(self, node):
- self._check_docstring('module', node)
- @check_messages('missing-docstring', 'empty-docstring')
- def visit_class(self, node):
- if self.config.no_docstring_rgx.match(node.name) is None:
- self._check_docstring('class', node)
- @check_messages('missing-docstring', 'empty-docstring')
- def visit_function(self, node):
- if self.config.no_docstring_rgx.match(node.name) is None:
- ftype = node.is_method() and 'method' or 'function'
- if isinstance(node.parent.frame(), astroid.Class):
- overridden = False
- confidence = (INFERENCE if has_known_bases(node.parent.frame())
- else INFERENCE_FAILURE)
- # check if node is from a method overridden by its ancestor
- for ancestor in node.parent.frame().ancestors():
- if node.name in ancestor and \
- isinstance(ancestor[node.name], astroid.Function):
- overridden = True
- break
- self._chec