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https://fuchsia.googlesource.com/third_party/github.com/pylint-dev/pylint
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572 lines
21 KiB
Python
572 lines
21 KiB
Python
# pylint: disable=W0611
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#
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# Copyright (c) 2003-2013 LOGILAB S.A. (Paris, FRANCE).
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# http://www.logilab.fr/ -- mailto:contact@logilab.fr
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#
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# This program is free software; you can redistribute it and/or modify it under
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# the terms of the GNU General Public License as published by the Free Software
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# Foundation; either version 2 of the License, or (at your option) any later
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# version.
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#
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# This program is distributed in the hope that it will be useful, but WITHOUT
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# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
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# FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
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#
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# You should have received a copy of the GNU General Public License along with
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# this program; if not, write to the Free Software Foundation, Inc.,
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# 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
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"""some functions that may be useful for various checkers
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"""
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import functools
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import re
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import sys
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import string
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import warnings
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import astroid
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from astroid import helpers
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from astroid import scoped_nodes
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from six.moves import map, builtins # pylint: disable=redefined-builtin
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BUILTINS_NAME = builtins.__name__
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COMP_NODE_TYPES = astroid.ListComp, astroid.SetComp, astroid.DictComp, astroid.GenExpr
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PY3K = sys.version_info[0] == 3
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if not PY3K:
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EXCEPTIONS_MODULE = "exceptions"
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else:
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EXCEPTIONS_MODULE = "builtins"
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ABC_METHODS = set(('abc.abstractproperty', 'abc.abstractmethod',
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'abc.abstractclassmethod', 'abc.abstractstaticmethod'))
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# Dictionary which maps the number of expected parameters a
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# special method can have to a set of special methods.
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# The following keys are used to denote the parameters restrictions:
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#
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# * None: variable number of parameters
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# * number: exactly that number of parameters
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# * tuple: this are the odd ones. Basically it means that the function
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# can work with any number of arguments from that tuple,
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# although it's best to implement it in order to accept
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# all of them.
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_SPECIAL_METHODS_PARAMS = {
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None: ('__new__', '__init__', '__call__'),
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0: ('__del__', '__repr__', '__str__', '__bytes__', '__hash__', '__bool__',
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'__dir__', '__len__', '__length_hint__', '__iter__', '__reversed__',
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'__neg__', '__pos__', '__abs__', '__invert__', '__complex__', '__int__',
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'__float__', '__neg__', '__pos__', '__abs__', '__complex__', '__int__',
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'__float__', '__index__', '__enter__', '__getnewargs_ex__',
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'__getnewargs__', '__getstate__', '__reduce__', '__copy__',
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'__unicode__', '__nonzero__'),
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1: ('__format__', '__lt__', '__le__', '__eq__', '__ne__', '__gt__',
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'__ge__', '__getattr__', '__getattribute__', '__delattr__',
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'__delete__', '__instancecheck__', '__subclasscheck__',
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'__getitem__', '__missing__', '__delitem__', '__contains__',
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'__add__', '__sub__', '__mul__', '__truediv__', '__floordiv__',
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'__mod__', '__divmod__', '__lshift__', '__rshift__', '__and__',
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'__xor__', '__or__', '__radd__', '__rsub__', '__rmul__', '__rtruediv__',
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'__rmod__', '__rdivmod__', '__rpow__', '__rlshift__', '__rrshift__',
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'__rand__', '__rxor__', '__ror__', '__iadd__', '__isub__', '__imul__',
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'__itruediv__', '__ifloordiv__', '__imod__', '__ilshift__',
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'__irshift__', '__iand__', '__ixor__', '__ior__', '__ipow__',
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'__setstate__', '__reduce_ex__', '__deepcopy__', '__cmp__',
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'__matmul__', '__rmatmul__'),
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2: ('__setattr__', '__get__', '__set__', '__setitem__'),
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3: ('__exit__', ),
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(0, 1): ('__round__', ),
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}
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SPECIAL_METHODS_PARAMS = {
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name: params
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for params, methods in _SPECIAL_METHODS_PARAMS.items()
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for name in methods
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}
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PYMETHODS = set(SPECIAL_METHODS_PARAMS)
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class NoSuchArgumentError(Exception):
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pass
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def is_inside_except(node):
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"""Returns true if node is inside the name of an except handler."""
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current = node
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while current and not isinstance(current.parent, astroid.ExceptHandler):
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current = current.parent
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return current and current is current.parent.name
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def get_all_elements(node):
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"""Recursively returns all atoms in nested lists and tuples."""
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if isinstance(node, (astroid.Tuple, astroid.List)):
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for child in node.elts:
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for e in get_all_elements(child):
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yield e
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else:
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yield node
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def clobber_in_except(node):
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"""Checks if an assignment node in an except handler clobbers an existing
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variable.
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Returns (True, args for W0623) if assignment clobbers an existing variable,
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(False, None) otherwise.
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"""
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if isinstance(node, astroid.AssAttr):
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return (True, (node.attrname, 'object %r' % (node.expr.as_string(),)))
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elif isinstance(node, astroid.AssName):
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name = node.name
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if is_builtin(name):
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return (True, (name, 'builtins'))
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else:
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stmts = node.lookup(name)[1]
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if (stmts and not isinstance(stmts[0].ass_type(),
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(astroid.Assign, astroid.AugAssign,
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astroid.ExceptHandler))):
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return (True, (name, 'outer scope (line %s)' % stmts[0].fromlineno))
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return (False, None)
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def is_super(node):
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"""return True if the node is referencing the "super" builtin function
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"""
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if getattr(node, 'name', None) == 'super' and \
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node.root().name == BUILTINS_NAME:
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return True
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return False
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def is_error(node):
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"""return true if the function does nothing but raising an exception"""
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for child_node in node.get_children():
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if isinstance(child_node, astroid.Raise):
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return True
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return False
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def is_raising(body):
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"""return true if the given statement node raise an exception"""
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for node in body:
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if isinstance(node, astroid.Raise):
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return True
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return False
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builtins = builtins.__dict__.copy()
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SPECIAL_BUILTINS = ('__builtins__',) # '__path__', '__file__')
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def is_builtin_object(node):
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"""Returns True if the given node is an object from the __builtin__ module."""
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return node and node.root().name == BUILTINS_NAME
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def is_builtin(name):
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"""return true if <name> could be considered as a builtin defined by python
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"""
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return name in builtins or name in SPECIAL_BUILTINS
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def is_defined_before(var_node):
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"""return True if the variable node is defined by a parent node (list,
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set, dict, or generator comprehension, lambda) or in a previous sibling
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node on the same line (statement_defining ; statement_using)
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"""
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varname = var_node.name
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_node = var_node.parent
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while _node:
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if isinstance(_node, COMP_NODE_TYPES):
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for ass_node in _node.nodes_of_class(astroid.AssName):
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if ass_node.name == varname:
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return True
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elif isinstance(_node, astroid.For):
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for ass_node in _node.target.nodes_of_class(astroid.AssName):
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if ass_node.name == varname:
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return True
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elif isinstance(_node, astroid.With):
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for expr, ids in _node.items:
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if expr.parent_of(var_node):
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break
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if (ids and
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isinstance(ids, astroid.AssName) and
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ids.name == varname):
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return True
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elif isinstance(_node, (astroid.Lambda, astroid.Function)):
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if _node.args.is_argument(varname):
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# If the name is found inside a default value
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# of a function, then let the search continue
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# in the parent's tree.
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if _node.args.parent_of(var_node):
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try:
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_node.args.default_value(varname)
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_node = _node.parent
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continue
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except astroid.NoDefault:
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pass
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return True
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if getattr(_node, 'name', None) == varname:
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return True
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break
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elif isinstance(_node, astroid.ExceptHandler):
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if isinstance(_node.name, astroid.AssName):
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ass_node = _node.name
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if ass_node.name == varname:
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return True
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_node = _node.parent
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# possibly multiple statements on the same line using semi colon separator
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stmt = var_node.statement()
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_node = stmt.previous_sibling()
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lineno = stmt.fromlineno
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while _node and _node.fromlineno == lineno:
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for ass_node in _node.nodes_of_class(astroid.AssName):
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if ass_node.name == varname:
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return True
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for imp_node in _node.nodes_of_class((astroid.From, astroid.Import)):
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if varname in [name[1] or name[0] for name in imp_node.names]:
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return True
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_node = _node.previous_sibling()
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return False
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def is_func_default(node):
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"""return true if the given Name node is used in function default argument's
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value
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"""
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parent = node.scope()
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if isinstance(parent, astroid.Function):
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for default_node in parent.args.defaults:
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for default_name_node in default_node.nodes_of_class(astroid.Name):
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if default_name_node is node:
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return True
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return False
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def is_func_decorator(node):
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"""return true if the name is used in function decorator"""
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parent = node.parent
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while parent is not None:
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if isinstance(parent, astroid.Decorators):
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return True
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if (parent.is_statement or
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isinstance(parent, astroid.Lambda) or
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isinstance(parent, (scoped_nodes.ComprehensionScope,
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scoped_nodes.ListComp))):
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break
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parent = parent.parent
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return False
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def is_ancestor_name(frame, node):
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"""return True if `frame` is a astroid.Class node with `node` in the
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subtree of its bases attribute
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"""
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try:
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bases = frame.bases
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except AttributeError:
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return False
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for base in bases:
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if node in base.nodes_of_class(astroid.Name):
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return True
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return False
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def assign_parent(node):
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"""return the higher parent which is not an AssName, Tuple or List node
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"""
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while node and isinstance(node, (astroid.AssName,
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astroid.Tuple,
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astroid.List)):
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node = node.parent
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return node
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def overrides_a_method(class_node, name):
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"""return True if <name> is a method overridden from an ancestor"""
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for ancestor in class_node.ancestors():
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if name in ancestor and isinstance(ancestor[name], astroid.Function):
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return True
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return False
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def check_messages(*messages):
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"""decorator to store messages that are handled by a checker method"""
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def store_messages(func):
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func.checks_msgs = messages
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return func
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return store_messages
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class IncompleteFormatString(Exception):
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"""A format string ended in the middle of a format specifier."""
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pass
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class UnsupportedFormatCharacter(Exception):
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"""A format character in a format string is not one of the supported
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format characters."""
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def __init__(self, index):
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Exception.__init__(self, index)
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self.index = index
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def parse_format_string(format_string):
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"""Parses a format string, returning a tuple of (keys, num_args), where keys
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is the set of mapping keys in the format string, and num_args is the number
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of arguments required by the format string. Raises
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IncompleteFormatString or UnsupportedFormatCharacter if a
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parse error occurs."""
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keys = set()
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num_args = 0
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def next_char(i):
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i += 1
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if i == len(format_string):
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raise IncompleteFormatString
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return (i, format_string[i])
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i = 0
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while i < len(format_string):
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char = format_string[i]
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if char == '%':
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i, char = next_char(i)
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# Parse the mapping key (optional).
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key = None
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if char == '(':
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depth = 1
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i, char = next_char(i)
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key_start = i
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while depth != 0:
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if char == '(':
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depth += 1
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elif char == ')':
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depth -= 1
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i, char = next_char(i)
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key_end = i - 1
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key = format_string[key_start:key_end]
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# Parse the conversion flags (optional).
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while char in '#0- +':
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i, char = next_char(i)
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# Parse the minimum field width (optional).
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if char == '*':
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num_args += 1
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i, char = next_char(i)
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else:
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while char in string.digits:
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i, char = next_char(i)
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# Parse the precision (optional).
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if char == '.':
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i, char = next_char(i)
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if char == '*':
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num_args += 1
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i, char = next_char(i)
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else:
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while char in string.digits:
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i, char = next_char(i)
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# Parse the length modifier (optional).
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if char in 'hlL':
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i, char = next_char(i)
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# Parse the conversion type (mandatory).
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if PY3K:
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flags = 'diouxXeEfFgGcrs%a'
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else:
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flags = 'diouxXeEfFgGcrs%'
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if char not in flags:
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raise UnsupportedFormatCharacter(i)
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if key:
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keys.add(key)
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elif char != '%':
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num_args += 1
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i += 1
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return keys, num_args
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def is_attr_protected(attrname):
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"""return True if attribute name is protected (start with _ and some other
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details), False otherwise.
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"""
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return attrname[0] == '_' and not attrname == '_' and not (
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attrname.startswith('__') and attrname.endswith('__'))
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def node_frame_class(node):
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"""return klass node for a method node (or a staticmethod or a
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classmethod), return null otherwise
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"""
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klass = node.frame()
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while klass is not None and not isinstance(klass, astroid.Class):
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if klass.parent is None:
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klass = None
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else:
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klass = klass.parent.frame()
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return klass
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def is_attr_private(attrname):
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"""Check that attribute name is private (at least two leading underscores,
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at most one trailing underscore)
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"""
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regex = re.compile('^_{2,}.*[^_]+_?$')
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return regex.match(attrname)
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def get_argument_from_call(callfunc_node, position=None, keyword=None):
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"""Returns the specified argument from a function call.
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:param callfunc_node: Node representing a function call to check.
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:param int position: position of the argument.
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:param str keyword: the keyword of the argument.
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:returns: The node representing the argument, None if the argument is not found.
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:raises ValueError: if both position and keyword are None.
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:raises NoSuchArgumentError: if no argument at the provided position or with
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the provided keyword.
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"""
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if position is None and keyword is None:
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raise ValueError('Must specify at least one of: position or keyword.')
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if position is not None:
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try:
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return callfunc_node.args[position]
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except IndexError:
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pass
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if keyword and callfunc_node.keywords:
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for arg in callfunc_node.keywords:
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if arg.arg == keyword:
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return arg.value
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raise NoSuchArgumentError
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def inherit_from_std_ex(node):
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"""
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Return true if the given class node is subclass of
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exceptions.Exception.
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"""
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if node.name in ('Exception', 'BaseException') \
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and node.root().name == EXCEPTIONS_MODULE:
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return True
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return any(inherit_from_std_ex(parent)
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for parent in node.ancestors(recurs=False))
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def error_of_type(handler, error_type):
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"""
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Check if the given exception handler catches
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the given error_type.
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The *handler* parameter is a node, representing an ExceptHandler node.
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The *error_type* can be an exception, such as AttributeError, or it
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can be a tuple of errors.
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The function will return True if the handler catches any of the
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given errors.
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"""
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if not isinstance(error_type, tuple):
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error_type = (error_type, )
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expected_errors = {error.__name__ for error in error_type}
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return handler.catch(expected_errors)
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def is_import_error(handler):
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warnings.warn("This function is deprecated in the favour of "
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"error_of_type. It will be removed in Pylint 1.6.",
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DeprecationWarning, stacklevel=2)
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return error_of_type(handler, ImportError)
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def decorated_with_property(node):
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""" Detect if the given function node is decorated with a property. """
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if not node.decorators:
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return False
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for decorator in node.decorators.nodes:
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if not isinstance(decorator, astroid.Name):
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continue
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try:
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for infered in decorator.infer():
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if isinstance(infered, astroid.Class):
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if (infered.root().name == BUILTINS_NAME and
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infered.name == 'property'):
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return True
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for ancestor in infered.ancestors():
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if (ancestor.name == 'property' and
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ancestor.root().name == BUILTINS_NAME):
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return True
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except astroid.InferenceError:
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pass
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def decorated_with(func, qnames):
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"""Determine if the `func` node has a decorator with the qualified name `qname`."""
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decorators = func.decorators.nodes if func.decorators else []
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for decorator_node in decorators:
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dec = safe_infer(decorator_node)
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if dec and dec.qname() in qnames:
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return True
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def unimplemented_abstract_methods(node, is_abstract_cb=None):
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"""
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Get the unimplemented abstract methods for the given *node*.
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A method can be considered abstract if the callback *is_abstract_cb*
|
|
returns a ``True`` value. The check defaults to verifying that
|
|
a method is decorated with abstract methods.
|
|
The function will work only for new-style classes. For old-style
|
|
classes, it will simply return an empty dictionary.
|
|
For the rest of them, it will return a dictionary of abstract method
|
|
names and their inferred objects.
|
|
"""
|
|
if is_abstract_cb is None:
|
|
is_abstract_cb = functools.partial(
|
|
decorated_with, qnames=ABC_METHODS)
|
|
visited = {}
|
|
try:
|
|
mro = reversed(node.mro())
|
|
except NotImplementedError:
|
|
# Old style class, it will not have a mro.
|
|
return {}
|
|
except astroid.ResolveError:
|
|
# Probably inconsistent hierarchy, don'try
|
|
# to figure this out here.
|
|
return {}
|
|
for ancestor in mro:
|
|
for obj in ancestor.values():
|
|
infered = obj
|
|
if isinstance(obj, astroid.AssName):
|
|
infered = safe_infer(obj)
|
|
if not infered:
|
|
continue
|
|
if not isinstance(infered, astroid.Function):
|
|
if obj.name in visited:
|
|
del visited[obj.name]
|
|
if isinstance(infered, astroid.Function):
|
|
# It's critical to use the original name,
|
|
# since after inferring, an object can be something
|
|
# else than expected, as in the case of the
|
|
# following assignment.
|
|
#
|
|
# class A:
|
|
# def keys(self): pass
|
|
# __iter__ = keys
|
|
abstract = is_abstract_cb(infered)
|
|
if abstract:
|
|
visited[obj.name] = infered
|
|
elif not abstract and obj.name in visited:
|
|
del visited[obj.name]
|
|
return visited
|
|
|
|
|
|
def node_ignores_exception(node, exception):
|
|
"""Check if the node is in a TryExcept which handles the given exception.
|
|
|
|
This will also return ``True`` if the node is protected by an `except Exception`
|
|
or by a bare except clause.
|
|
"""
|
|
current = node
|
|
ignores = (astroid.ExceptHandler, astroid.TryExcept)
|
|
while current and not isinstance(current.parent, ignores):
|
|
current = current.parent
|
|
|
|
func = functools.partial(error_of_type,
|
|
error_type=(Exception, exception))
|
|
if current and isinstance(current.parent, astroid.TryExcept):
|
|
handles_errors = any(map(func, current.parent.handlers))
|
|
empty_handlers = any(handler.type is None
|
|
for handler in current.parent.handlers)
|
|
if handles_errors or empty_handlers:
|
|
return True
|
|
return False
|
|
|
|
|
|
# TODO(cpopa): deprecate these or leave them as aliases?
|
|
safe_infer = astroid.helpers.safe_infer
|
|
has_known_bases = astroid.helpers.has_known_bases
|