# 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., # 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. """basic checker for Python code""" import sys import astroid from logilab.common.ureports import Table from astroid import are_exclusive import astroid.bases from pylint.interfaces import IAstroidChecker 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, ) import re # 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('__.*__') del re 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 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): continue for _ in child.nodes_of_class(astroid.Break, skip_klass=loop_nodes): return True return False 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 ('__builtin__.property', 'abc.abstractproperty')): 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 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).'), '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.'), '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.'), } def __init__(self, linter): _BasicChecker.__init__(self, linter) @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 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) 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 the exec statement', 'exec-statement', 'Used when you use the "exec" statement, to discourage its \ usage. That doesn\'t mean you can not use it !', {'maxversion': (3, 0)}), '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.'), 'W0142': ('Used * or ** magic', 'star-args', 'Used when a function or method is called using `*args` or ' '`**kwargs` to dispatch arguments. This doesn\'t improve ' 'readability and should be used with care.'), '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.'), 'W0121': ('Use raise ErrorClass(args) instead of raise ErrorClass, args.', 'old-raise-syntax', "Used when the alternate raise syntax 'raise foo, bar' is used " "instead of 'raise foo(bar)'.", {'maxversion': (3, 0)}), 'C0121': ('Missing required attribute "%s"', # W0103 'missing-module-attribute', 'Used when an attribute required for modules is missing.'), } options = (('required-attributes', {'default' : (), 'type' : 'csv', 'metavar' : '', 'help' : 'Required attributes for module, separated by a ' 'comma'} ), ('bad-functions', {'default' : ('map', 'filter', 'apply', 'input'), 'type' :'csv', 'metavar' : '', '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): """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, basestring): # treat string statement in a separated message 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 xrange(len(ordinary_args)): if not isinstance(call.args[i], astroid.Name): return if node.args.args[i].name != call.args[i].name: 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 # check for dangerous default values as arguments for default in node.args.defaults: try: value = default.infer().next() except astroid.InferenceError: continue builtins = astroid.bases.BUILTINS if (isinstance(value, astroid.Instance) and value.qname() in ['.'.join([builtins, x]) for x in ('set', 'dict', 'list')]): if value is default: msg = default.as_string() elif type(value) is astroid.Instance: msg = '%s (%s)' % (default.as_string(), value.qname()) else: msg = '%s (%s)' % (default.as_string(), value.as_string()) 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', 'old-raise-syntax') def visit_raise(self, node): """check if the node has a right sibling (if so, that's some unreachable code) """ self._check_unreachable(node) if sys.version_info >= (3, 0): return if node.exc is not None and node.inst is not None and node.tback is None: self.add_message('old-raise-syntax', node=node) @check_messages('exec-statement') def visit_exec(self, node): """just print a warning on exec statements""" self.add_message('exec-statement', node=node) @check_messages('bad-builtin', 'star-args') 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 in self.config.bad_functions: self.add_message('bad-builtin', node=node, args=name) if node.starargs or node.kwargs: scope = node.scope() if isinstance(scope, astroid.Function): toprocess = [(n, vn) for (n, vn) in ((node.starargs, scope.args.vararg), (node.kwargs, scope.args.kwarg)) if n] if toprocess: for cfnode, fargname in toprocess[:]: if getattr(cfnode, 'name', None) == fargname: toprocess.remove((cfnode, fargname)) if not toprocess: return # star-args can be skipped self.add_message('star-args', node=node.func) @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): """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 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"', 'invalid-name', 'Used when the name doesn\'t match the regular expression \ associated to its type (constant, variable, class...).'), } options = (('module-rgx', {'default' : MOD_NAME_RGX, 'type' :'regexp', 'metavar' : '', 'help' : 'Regular expression which should only match correct ' 'module names'} ), ('const-rgx', {'default' : CONST_NAME_RGX, 'type' :'regexp', 'metavar' : '', 'help' : 'Regular expression which should only match correct ' 'module level names'} ), ('class-rgx', {'default' : CLASS_NAME_RGX, 'type' :'regexp', 'metavar' : '', 'help' : 'Regular expression which should only match correct ' 'class names'} ), ('function-rgx', {'default' : DEFAULT_NAME_RGX, 'type' :'regexp', 'metavar' : '', 'help' : 'Regular expression which should only match correct ' 'function names'} ), ('method-rgx', {'default' : DEFAULT_NAME_RGX, 'type' :'regexp', 'metavar' : '', 'help' : 'Regular expression which should only match correct ' 'method names'} ), ('attr-rgx', {'default' : DEFAULT_NAME_RGX, 'type' :'regexp', 'metavar' : '', 'help' : 'Regular expression which should only match correct ' 'instance attribute names'} ), ('argument-rgx', {'default' : DEFAULT_NAME_RGX, 'type' :'regexp', 'metavar' : '', 'help' : 'Regular expression which should only match correct ' 'argument names'}), ('variable-rgx', {'default' : DEFAULT_NAME_RGX, 'type' :'regexp', 'metavar' : '', 'help' : 'Regular expression which should only match correct ' 'variable names'} ), ('class-attribute-rgx', {'default' : CLASS_ATTRIBUTE_RGX, 'type' :'regexp', 'metavar' : '', 'help' : 'Regular expression which should only match correct ' 'attribute names in class bodies'} ), ('inlinevar-rgx', {'default' : COMP_VAR_RGX, 'type' :'regexp', 'metavar' : '', 'help' : 'Regular expression which should only match correct ' 'list comprehension / generator expression variable \ names'} ), # XXX use set ('good-names', {'default' : ('i', 'j', 'k', 'ex', 'Run', '_'), 'type' :'csv', 'metavar' : '', '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' : '', 'help' : 'Bad variable names which should always be refused, ' 'separated by a comma'} ), ) 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) @check_messages('blacklisted-name', 'invalid-name') def visit_module(self, node): self._check_name('module', node.name.split('.')[-1], node) @check_messages('blacklisted-name', 'invalid-name') def visit_class(self, node): self._check_name('class', node.name, node) for attr, anodes in node.instance_attrs.iteritems(): 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. if node.is_method() and overrides_a_method(node.parent.frame(), node.name): return self._check_name(_determine_function_name_type(node), node.name, node) # 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: 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(): 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 """ 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 _check_name(self, node_type, name, node): """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') if regexp.match(name) is None: type_label = {'inlinedvar': 'inlined variable', 'const': 'constant', 'attr': 'attribute', 'class_attribute': 'class attribute' }.get(node_type, node_type) self.add_message('invalid-name', node=node, args=(type_label, name)) self.stats['badname_' + node_type] += 1 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' : '', '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' : '', '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 # 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 if not overridden: self._check_docstring(ftype, node) else: self._check_docstring(ftype, node) def _check_docstring(self, node_type, node): """check the node has a non empty docstring""" docstring = node.doc if docstring is None: if node.body: lines = node.body[-1].lineno - node.body[0].lineno + 1 else: lines = 0 max_lines = self.config.docstring_min_length if node_type != 'module' and max_lines > -1 and lines < max_lines: return self.stats['undocumented_'+node_type] += 1 self.add_message('missing-docstring', node=node, args=(node_type,)) elif not docstring.strip(): self.stats['undocumented_'+node_type] += 1 self.add_message('empty-docstring', node=node, args=(node_type,)) class PassChecker(_BasicChecker): """check if the pass statement is really necessary""" msgs = {'W0107': ('Unnecessary pass statement', 'unnecessary-pass', 'Used when a "pass" statement that can be avoided is ' 'encountered.'), } @check_messages('unnecessary-pass') def visit_pass(self, node): if len(node.parent.child_sequence(node)) > 1: self.add_message('unnecessary-pass', node=node) class LambdaForComprehensionChecker(_BasicChecker): """check for using a lambda where a comprehension would do. See where GvR says comprehensions would be clearer. """ msgs = {'W0110': ('map/filter on lambda could be replaced by comprehension', 'deprecated-lambda', 'Used when a lambda is the first argument to "map" or ' '"filter". It could be clearer as a list ' 'comprehension or generator expression.', {'maxversion': (3, 0)}), } @check_messages('deprecated-lambda') def visit_callfunc(self, node): """visit a CallFunc node, check if map or filter are called with a lambda """ if not node.args: return if not isinstance(node.args[0], astroid.Lambda): return infered = safe_infer(node.func) if (is_builtin_object(infered) and infered.name in ['map', 'filter']): self.add_message('deprecated-lambda', node=node) def register(linter): """required method to auto register this checker""" linter.register_checker(BasicErrorChecker(linter)) linter.register_checker(BasicChecker(linter)) linter.register_checker(NameChecker(linter)) linter.register_checker(DocStringChecker(linter)) linter.register_checker(PassChecker(linter)) linter.register_checker(LambdaForComprehensionChecker(linter))