# copyright 2003-2013 LOGILAB S.A. (Paris, FRANCE), all rights reserved.
# contact http://www.logilab.fr/ -- mailto:[email protected]
#
# This file is part of astroid.
#
# astroid is free software: you can redistribute it and/or modify it
# under the terms of the GNU Lesser General Public License as published by the
# Free Software Foundation, either version 2.1 of the License, or (at your
# option) any later version.
#
# astroid 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 Lesser General Public License
# for more details.
#
# You should have received a copy of the GNU Lesser General Public License along
# with astroid. If not, see <http://www.gnu.org/licenses/>.
"""This module contains the classes for "scoped" node, i.e. which are opening a
new local scope in the language definition : Module, Class, Function (and
Lambda, GenExpr, DictComp and SetComp to some extent).
"""
from __future__ import with_statement
__doctype__ = "restructuredtext en"
import sys
import warnings
from itertools import chain
try:
from io import BytesIO
except ImportError:
from cStringIO import StringIO as BytesIO
import six
from logilab.common.compat import builtins
from logilab.common.decorators import cached, cachedproperty
from astroid.exceptions import NotFoundError, \
AstroidBuildingException, InferenceError, ResolveError
from astroid.node_classes import Const, DelName, DelAttr, \
Dict, From, List, Pass, Raise, Return, Tuple, Yield, YieldFrom, \
LookupMixIn, const_factory as cf, unpack_infer, Name, CallFunc
from astroid.bases import NodeNG, InferenceContext, Instance,\
YES, Generator, UnboundMethod, BoundMethod, _infer_stmts, \
BUILTINS
from astroid.mixins import FilterStmtsMixin
from astroid.bases import Statement
from astroid.manager import AstroidManager
ITER_METHODS = ('__iter__', '__getitem__')
PY3K = sys.version_info >= (3, 0)
def _c3_merge(sequences):
"""Merges MROs in *sequences* to a single MRO using the C3 algorithm.
Adapted from http://www.python.org/download/releases/2.3/mro/.
"""
result = []
while True:
sequences = [s for s in sequences if s] # purge empty sequences
if not sequences:
return result
for s1 in sequences: # find merge candidates among seq heads
candidate = s1[0]
for s2 in sequences:
if candidate in s2[1:]:
candidate = None
break # reject the current head, it appears later
else:
break
if not candidate:
# Show all the remaining bases, which were considered as
# candidates for the next mro sequence.
bases = ["({})".format(", ".join(base.name
for base in subsequence))
for subsequence in sequences]
raise ResolveError("Cannot create a consistent method resolution "
"order for bases %s" % ", ".join(bases))
result.append(candidate)
# remove the chosen candidate
for seq in sequences:
if seq[0] == candidate:
del seq[0]
def _verify_duplicates_mro(sequences):
for sequence in sequences:
names = [node.qname() for node in sequence]
if len(names) != len(set(names)):
raise ResolveError('Duplicates found in the mro.')
def remove_nodes(func, cls):
def wrapper(*args, **kwargs):
nodes = [n for n in func(*args, **kwargs) if not isinstance(n, cls)]
if not nodes:
raise NotFoundError()
return nodes
return wrapper
def function_to_method(n, klass):
if isinstance(n, Function):
if n.type == 'classmethod':
return BoundMethod(n, klass)
if n.type != 'staticmethod':
return UnboundMethod(n)
return n
def std_special_attributes(self, name, add_locals=True):
if add_locals:
locals = self.locals
else:
locals = {}
if name == '__name__':
return [cf(self.name)] + locals.get(name, [])
if name == '__doc__':
return [cf(self.doc)] + locals.get(name, [])
if name == '__dict__':
return [Dict()] + locals.get(name, [])
raise NotFoundError(name)
MANAGER = AstroidManager()
def builtin_lookup(name):
"""lookup a name into the builtin module
return the list of matching statements and the astroid for the builtin
module
"""
builtin_astroid = MANAGER.ast_from_module(builtins)
if name == '__dict__':
return builtin_astroid, ()
try:
stmts = builtin_astroid.locals[name]
except KeyError:
stmts = ()
return builtin_astroid, stmts
# TODO move this Mixin to mixins.py; problem: 'Function' in _scope_lookup
class LocalsDictNodeNG(LookupMixIn, NodeNG):
""" this class provides locals handling common to Module, Function
and Class nodes, including a dict like interface for direct access
to locals information
"""
# attributes below are set by the builder module or by raw factories
# dictionary of locals with name as key and node defining the local as
# value
def qname(self):
"""return the 'qualified' name of the node, eg module.name,
module.class.name ...
"""
if self.parent is None:
return self.name
return '%s.%s' % (self.parent.frame().qname(), self.name)
def frame(self):
"""return the first parent frame node (i.e. Module, Function or Class)
"""
return self
def scope(self):
"""return the first node defining a new scope (i.e. Module,
Function, Class, Lambda but also GenExpr, DictComp and SetComp)
"""
return self
def _scope_lookup(self, node, name, offset=0):
"""XXX method for interfacing the scope lookup"""
try:
stmts = node._filter_stmts(self.locals[name], self, offset)
except KeyError:
stmts = ()
if stmts:
return self, stmts
if self.parent: # i.e. not Module
# nested scope: if parent scope is a function, that's fine
# else jump to the module
pscope = self.parent.scope()
if not pscope.is_function:
pscope = pscope.root()
return pscope.scope_lookup(node, name)
return builtin_lookup(name) # Module
def set_local(self, name, stmt):
"""define <name> in locals (<stmt> is the node defining the name)
if the node is a Module node (i.e. has globals), add the name to
globals
if the name is already defined, ignore it
"""
#assert not stmt in self.locals.get(name, ()), (self, stmt)
self.locals.setdefault(name, []).append(stmt)
__setitem__ = set_local
def _append_node(self, child):
"""append a child, linking it in the tree"""
self.body.append(child)
child.parent = self
def add_local_node(self, child_node, name=None):
"""append a child which should alter locals to the given node"""
if name != '__class__':
# add __class__ node as a child will cause infinite recursion later!
self._append_node(child_node)
self.set_local(name or child_node.name, child_node)
def __getitem__(self, item):
"""method from the `dict` interface returning the first node
associated with the given name in the locals dictionary
:type item: str
:param item: the name of the locally defined object
:raises KeyError: if the name is not defined
"""
return self.locals[item][0]
def __iter__(self):
"""method from the `dict` interface returning an iterator on
`self.keys()`
"""
return iter(self.keys())
def keys(self):
"""method from the `dict` interface returning a tuple containing
locally defined names
"""
return list(self.locals.keys())
def values(self):
"""method from the `dict` interface returning a tuple containing
locally defined nodes which are instance of `Function` or `Class`
"""
return [self[key] for key in self.keys()]
def items(self):
"""method from the `dict` interface returning a list of tuple
containing each locally defined name with its associated node,
which is an instance of `Function` or `Class`
"""
return list(zip(self.keys(), self.values()))
def __contains__(self, name):
return name in self.locals
has_key = __contains__
# Module #####################################################################
class Module(LocalsDictNodeNG):
_astroid_fields = ('body',)
fromlineno = 0
lineno = 0
# attributes below are set by the builder module or by raw factories
# the file from which as been extracted the astroid representation. It may
# be None if the representation has been built from a built-in module
file = None
# Alternatively, if built from a string/bytes, this can be set
file_bytes = None
# encoding of python source file, so we can get unicode out of it (python2
# only)
file_encoding = None
# the module name
name = None
# boolean for astroid built from source (i.e. ast)
pure_python = None
# boolean for package module
package = None
# dictionary of globals with name as key and node defining the global
# as value
globals = None
# Future imports
future_imports = None
# names of python special attributes (handled by getattr impl.)
special_attributes = set(('__name__', '__doc__', '__file__', '__path__',
'__dict__'))
# names of module attributes available through the global scope
scope_attrs = set(('__name__', '__doc__', '__file__', '__path__'))
def __init__(self, name, doc, pure_python=True):
self.name = name
self.doc = doc
self.pure_python = pure_python
self.locals = self.globals = {}
self.body = []
self.future_imports = set()
def _get_stream(self):
if self.file_bytes is not None:
return BytesIO(self.file_bytes)
if self.file is not None:
stream = open(self.file, 'rb')
return stream
return None
@property
def file_stream(self):
warnings.warn("file_stream property is deprecated and "
"it is slated for removal in astroid 1.6."
"Use the new method 'stream' instead.",
PendingDeprecationWarning,
stacklevel=2)
return self._get_stream()
def stream(self):
"""Get a stream to the underlying file or bytes."""
return self._get_stream()
def close(self):
"""Close the underlying file streams."""
warnings.warn("close method is deprecated and it is "
"slated for removal in astroid 1.6, along "
"with 'file_stream' property. "
"Its behaviour is replaced by managing each "
"file stream returned by the 'stream' method.",
PendingDeprecationWarning,
stacklevel=2)
def block_range(self, lineno):
"""return block line numbers.
start from the beginning whatever the given lineno
"""
return self.fromlineno, self.tolineno
def scope_lookup(self, node, name, offset=0):
if name in self.scope_attrs and not name in self.locals:
try:
return self, self.getattr(name)
except NotFoundError:
return self, ()
return self._scope_lookup(node, name, offset)
def pytype(self):
return '%s.module' % BUILTINS
def display_type(self):
return 'Module'
def getattr(self, name, context=None, ignore_locals=False):
if name in self.special_attributes:
if name == '__file__':
return [cf(self.file)] + self.locals.get(name, [])
if name == '__path__' and self.package:
return [List()] + self.locals.get(name, [])
return std_special_attributes(self, name)
if not ignore_locals and name in self.locals:
return self.locals[name]
if self.package:
try:
return [self.import_module(name, relative_only=True)]
except AstroidBuildingException:
raise NotFoundError(name)
except SyntaxError:
raise NotFoundError(name)
except Exception:# XXX pylint tests never pass here; do we need it?
import traceback
traceback.print_exc()
raise NotFoundError(name)
getattr = remove_nodes(getattr, DelName)
def igetattr(self, name, context=None):
"""inferred getattr"""
# set lookup name since this is necessary to infer on import nodes for
# instance
if not context:
context = InferenceContext()
try:
return _infer_stmts(self.getattr(name, context), context, frame=self, lookupname=name)
except NotFoundError:
raise InferenceError(name)
def fully_defined(self):
"""return True if this module has been built from a .py file
and so contains a complete representation including the code
"""
return self.file is not None and self.file.endswith('.py')
def statement(self):
"""return the first parent node marked as statement node
consider a module as a statement...
"""
return self
def previous_sibling(self):
"""module has no sibling"""
return
def next_sibling(self):
"""module has no sibling"""
return
if sys.version_info < (2, 8):
@cachedproperty
def _absolute_import_activated(self):
for stmt in self.locals.get('absolute_import', ()):
if isinstance(stmt, From) and stmt.modname == '__future__':
return True
return False
else:
_absolute_import_activated = True
def absolute_import_activated(self):
return self._absolute_import_activated
def import_module(self, modname, relative_only=False, level=None):
"""import the given module considering self as context"""
if relative_only and level is None:
level = 0
absmodname = self.relative_to_absolute_name(modname, level)
try:
return MANAGER.ast_from_module_name(absmodname)
except AstroidBuildingException:
# we only want to import a sub module or package of this module,
# skip here
if relative_only:
raise
return MANAGER.ast_from_module_name(modname)
def relative_to_absolute_name(self, modname, level):
"""return the absolute module name for a relative import.
The relative import can be implicit or explicit.
"""
# XXX this returns non sens when called on an absolute import
# like 'pylint.checkers.astroid.utils'
# XXX doesn't return absolute name if self.name isn't absolute name
if self.absolute_import_activated() and level is None:
return modname
if level:
if self.package:
level = level - 1
package_name = self.name.rsplit('.', level)[0]
elif self.package:
package_name = self.name
else:
package_name = self.name.rsplit('.', 1)[0]
if package_name:
if not modname:
return package_name
return '%s.%s' % (package_name, modname)
return modname
def wildcard_import_names(self):
"""return the list of imported names when this module is 'wildcard
imported'
It doesn't include the '__builtins__' name which is added by the
current CPython implementation of wildcard imports.
"""
# take advantage of a living module if it exists
try:
living = sys.modules[self.name]
except KeyError:
pass
else:
try:
return living.__all__
except AttributeError:
return [name for name in living.__dict__.keys()
if not name.startswith('_')]
# else lookup the astroid
#
# We separate the different steps of lookup in try/excepts
# to avoid catching too many Exceptions
default = [name for name in self.keys() if not name.startswith('_')]
try:
all = self['__all__']
except KeyError:
return default
try:
explicit = next(all.assigned_stmts())
except InferenceError:
return default
except AttributeError:
# not an assignment node
# XXX infer?
return default
# Try our best to detect the exported name.
infered = []
try:
explicit = next(explicit.infer())
except InferenceError:
return default
if not isinstance(explicit, (Tuple, List)):
return default
str_const = lambda node: (isinstance(node, Const) and
isinstance(node.value, six.string_types))
for node in explicit.elts:
if str_const(node):
infered.append(node.value)
else:
try:
infered_node = next(node.infer())
except InferenceError:
continue
if str_const(infered_node):
infered.append(infered_node.value)
return infered
class ComprehensionScope(LocalsDictNodeNG):
def frame(self):
return self.parent.frame()
scope_lookup = LocalsDictNodeNG._scope_lookup
class GenExpr(ComprehensionScope):
_astroid_fields = ('elt', 'generators')
def __init__(self):
self.locals = {}
self.elt = None
self.generators = []
class DictComp(ComprehensionScope):
_astroid_fields = ('key', 'value', 'generators')
def __init__(self):
self.locals = {}
self.key = None
self.value = None
self.generators = []
class SetComp(ComprehensionScope):
_astroid_fields = ('elt', 'generators')
def __init__(self):
self.locals = {}
self.elt = None
self.generators = []
class _ListComp(NodeNG):
"""class representing a ListComp node"""
_astroid_fields = ('elt', 'generators')
elt = None
generators = None
if sys.version_info >= (3, 0):
class ListComp(_ListComp, ComprehensionScope):
"""class representing a ListComp node"""
def __init__(self):
self.locals = {}
else:
class ListComp(_ListComp):
"""class representing a ListComp node"""
# Function ###################################################################
def _infer_decorator_callchain(node):
"""Detect decorator call chaining and see if the end result is a
static or a classmethod.
"""
if not isinstance(node, Function):
return
if not node.parent:
return
try:
# TODO: We don't handle multiple inference results right now,
# because there's no flow to reason when the return
# is what we are looking for, a static or a class method.
result = next(node.infer_call_result(node.parent))
except (StopIteration, InferenceError):
return
if isinstance(result, Instance):
result = result._proxied
if isinstance(result, Class):
if result.is_subtype_of('%s.classmethod' % BUILTINS):
return 'classmethod'
if result.is_subtype_of('%s.staticmethod' % BUILTINS):
return 'staticmethod'
def _function_type(self):
"""
Function type, possible values are:
method, function, staticmethod, classmethod.
"""
# Can't infer that this node is decorated
# with a subclass of `classmethod` where `type` is first set,
# so do it here.
if self.decorators:
for node in self.decorators.nodes:
if isinstance(node, CallFunc):
# Handle the following case:
# @some_decorator(arg1, arg2)
# def func(...)
#
try:
current = next(node.func.infer())
except InferenceError:
continue
_type = _infer_decorator_callchain(current)
if _type is not None:
return _type
try:
for infered in node.infer():
# Check to see if this returns a static or a class method.
_type = _infer_decorator_callchain(infered)
if _type is not None:
return _type
if not isinstance(infered, Class):
continue
for ancestor in infered.ancestors():
if not isinstance(ancestor, Class):
continue
if ancestor.is_subtype_of('%s.classmethod' % BUILTINS):
return 'classmethod'
elif ancestor.is_subtype_of('%s.staticmethod' % BUILTINS):
return 'staticmethod'
except InferenceError:
pass
return self._type
class Lambda(LocalsDictNodeNG, FilterStmtsMixin):
_astroid_fields = ('args', 'body',)
name = '<lambda>'
# function's type, 'function' | 'method' | 'staticmethod' | 'classmethod'
type = 'function'
def __init__(self):
self.locals = {}
self.args = []
self.body = []
def pytype(self):
if 'method' in self.type:
return '%s.instancemethod' % BUILTINS
return '%s.function' % BUILTINS
def display_type(self):
if 'method' in self.type:
return 'Method'
return 'Function'
def callable(self):
return True
def argnames(self):
"""return a list of argument names"""
if self.args.args: # maybe None with builtin functions
names = _rec_get_names(self.args.args)
else:
names = []
if self.args.vararg:
names.append(self.args.vararg)
if self.args.kwarg:
names.append(self.args.kwarg)
return names
def infer_call_result(self, caller, context=None):
"""infer what a function is returning when called"""
return self.body.infer(context)
def scope_lookup(self, node, name, offset=0):
if node in self.args.defaults or node in self.args.kw_defaults:
frame = self.parent.frame()
# line offset to avoid that def func(f=func) resolve the default
# value to the defined function
offset = -1
else:
# check this is not used in function decorators
frame = self
return frame._scope_lookup(node, name, offset)
class Function(Statement, Lambda):
if PY3K:
_astroid_fields = ('decorators', 'args', 'body', 'returns')
returns = None
else:
_astroid_fields = ('decorators', 'args', 'body')
special_attributes = set(('__name__', '__doc__', '__dict__'))
is_function = True
# attributes below are set by the builder module or by raw factories
blockstart_tolineno = None
decorators = None
_type = "function"
type = cachedproperty(_function_type)
def __init__(self, name, doc):
self.locals = {}
self.args = []
self.body = []
self.name = name
self.doc = doc
self.extra_decorators = []
self.instance_attrs = {}
@cachedproperty
def fromlineno(self):
# lineno is the line number of the first decorator, we want the def
# statement lineno
lineno = self.lineno
if self.decorators is not None:
lineno += sum(node.tolineno - node.lineno + 1
for node in self.decorators.nodes)
return lineno
@cachedproperty
def blockstart_tolineno(self):
return self.args.tolineno
def block_range(self, lineno):
"""return block line numbers.
start from the "def" position whatever the given lineno
"""
return self.fromlineno, self.tolineno
def getattr(self, name, context=None):
"""this method doesn't look in the instance_attrs dictionary since it's
done by an Instance proxy at inference time.
"""
if name == '__module__':
return [cf(self.root().qname())]
if name in self.instance_attrs:
return self.instance_attrs[name]
return std_special_attributes(self, name, False)
def is_method(self):
"""return true if the function node should be considered as a method"""
# check we are defined in a Class, because this is usually expected
# (e.g. pylint...) when is_method() return True
return self.type != 'function' and isinstance(self.parent.frame(), Class)
def decoratornames(self):
"""return a list of decorator qualified names"""
result = set()
decoratornodes = []
if self.decorators is not None:
decoratornodes += self.decorators.nodes
decoratornodes += self.extra_decorators
for decnode in decoratornodes:
for infnode in decnode.infer():
result.add(infnode.qname())
return result
decoratornames = cached(decoratornames)
def is_bound(self):
"""return true if the function is bound to an Instance or a class"""
return self.type == 'classmethod'
def is_abstract(self, pass_is_abstract=True):
"""Returns True if the method is abstract.
A method is considered abstract if
- the only statement is 'raise NotImplementedError', or
- the only statement is 'pass' and pass_is_abstract is True, or
- the method is annotated with abc.astractproperty/abc.abstractmethod
"""
if self.decorators:
for node in self.decorators.nodes:
try:
infered = next(node.infer())
except InferenceError:
continue
if infered and infered.qname() in ('abc.abstractproperty',
'abc.abstractmethod'):
return True
for child_node in self.body:
if isinstance(child_node, Raise):
if child_node.raises_not_implemented():
return True
if pass_is_abstract and isinstance(child_node, Pass):
return True
return False
# empty function is the same as function with a single "pass" statement
if pass_is_abstract:
return True
def is_generator(self):
"""return true if this is a generator function"""
# XXX should be flagged, not computed
return next(self.nodes_of_class((Yield, YieldFrom),
skip_klass=(Function, Lambda)), False)
def infer_call_result(self, caller, context=None):
"""infer what a function is returning when called"""
if self.is_generator():
yield Generator()
return
# This is really a gigantic hack to work around metaclass generators
# that return transient class-generating functions. Pylint's AST structure
# cannot handle a base class object that is only used for calling __new__,
# but does not contribute to the inheritance structure itself. We inject
# a fake class into the hierarchy here for several well-known metaclass
# generators, and filter it out later.
if (self.name == 'with_metaclass' and
len(self.args.args) == 1 and
self.args.vararg is not None):
metaclass = next(caller.args[0].infer(context))
if isinstance(metaclass, Class):
c = Class('temporary_class', None)
c.hide = True
c.parent = self
c.bases = [next(b.infer(context)) for b in caller.args[1:]]
c._metaclass = metaclass
yield c
return
returns = self.nodes_of_class(Return, skip_klass=Function)
for returnnode in returns:
if returnnode.value is None:
yield Const(None)
else:
try:
for infered in returnnode.value.infer(context):
yield infered
except InferenceError:
yield YES
def _rec_get_names(args, names=None):
"""return a list of all argument names"""
if names is None:
names = []
for arg in args:
if isinstance(arg, Tuple):
_rec_get_names(arg.elts, names)
else:
names.append(arg.name)
return names
# Class ######################################################################
def _is_metaclass(klass, seen=None):
""" Return if the given class can be
used as a metaclass.
"""
if klass.name == 'type':
return True
if seen is None:
seen = set()
for base in klass.bases:
try:
for baseobj in base.infer():
if baseobj in seen:
continue
else:
seen.add(baseobj)
if isinstance(baseobj, Instance):
# not abstract
return False
if baseobj is YES:
continue
if baseobj is klass:
continue
if not isinstance(baseobj, Class):
continue
if baseobj._type == 'metaclass':
return True
if _is_metaclass(baseobj, seen):
return True
except InferenceError:
continue
return False
def _class_type(klass, ancestors=None):
"""return a Class node type to differ metaclass, interface and exception
from 'regular' classes
"""
# XXX we have to store ancestors in case we have a ancestor loop
if klass._type is not None:
return klass._type
if _is_metaclass(klass):
klass._type = 'metaclass'
elif klass.name.endswith('Interface'):
klass._type = 'interface'
elif klass.name.endswith('Exception'):
klass._type = 'exception'
else:
if ancestors is None:
ancestors = set()
if klass in ancestors:
# XXX we are in loop ancestors, and have found no type
klass._type = 'class'
return 'class'
ancestors.add(klass)
for base in klass.ancestors(recurs=False):
name = _class_type(base, ancestors)
if name != 'class':
if name == 'metaclass' and not _is_metaclass(klass):
# don't propagate it if the current class
# can't be a metaclass
continue
klass._type = base.type
break
if klass._type is None:
klass._type = 'class'
return klass._type
def _iface_hdlr(iface_node):
"""a handler function used by interfaces to handle suspicious
interface nodes
"""
return True
class Class(Statement, LocalsDictNodeNG, FilterStmtsMixin):
# some of the attributes below are set by the builder module or
# by a raw factories
# a dictionary of class instances attributes
_astroid_fields = ('decorators', 'bases', 'body') # name
decorators = None
special_attributes = set(('__name__', '__doc__', '__dict__', '__module__',
'__bases__', '__mro__', '__subclasses__'))
blockstart_tolineno = None
_type = None
_metaclass_hack = False
hide = False
type = property(_class_type,
doc="class'type, possible values are 'class' | "
"'metaclass' | 'interface' | 'exception'")
def __init__(self, name, doc):
self.instance_attrs = {}
self.locals = {}
self.bases = []
self.body = []
self.name = name
self.doc = doc
def _newstyle_impl(self, context=None):
if context is None:
context = InferenceContext()
if self._newstyle is not None:
return self._newstyle
for base in self.ancestors(recurs=False, context=context):
if base._newstyle_impl(context):
self._newstyle = True
break
klass = self._explicit_metaclass()
# could be any callable, we'd need to infer the result of klass(name,
# bases, dict). punt if it's not a class node.
if klass is not None and isinstance(klass, Class):
self._newstyle = klass._newstyle_impl(context)
if self._newstyle is None:
self._newstyle = False
return self._newstyle
_newstyle = None
newstyle = property(_newstyle_impl,
doc="boolean indicating if it's a new style class"
"or not")
@cachedproperty
def blockstart_tolineno(self):
if self.bases:
return self.bases[-1].tolineno
else:
return self.fromlineno
def block_range(self, lineno):
"""return block line numbers.
start from the "class" position whatever the given lineno
"""
return self.fromlineno, self.tolineno
def pytype(self):
if self.newstyle:
return '%s.type' % BUILTINS
return '%s.classobj' % BUILTINS
def display_type(self):
return 'Class'
def callable(self):
return True
def is_subtype_of(self, type_name, context=None):
if self.qname() == type_name:
return True
for anc in self.ancestors(context=context):
if anc.qname() == type_name:
return True
def infer_call_result(self, caller, context=None):
"""infer what a class is returning when called"""
if self.is_subtype_of('%s.type' % (BUILTINS,), context) and len(caller.args) == 3:
name_node = next(caller.args[0].infer(context))
if (isinstance(name_node, Const) and
isinstance(name_node.value, six.string_types)):
name = name_node.value
else:
yield YES
return
result = Class(name, None)
bases = next(caller.args[1].infer(context))
if isinstance(bases, (Tuple, List)):
result.bases = bases.itered()
else:
# There is currently no AST node that can represent an 'unknown'
# node (YES is not an AST node), therefore we simply return YES here
# although we know at least the name of the class.
yield YES
return
result.parent = caller.parent
yield result
else:
yield Instance(self)
def scope_lookup(self, node, name, offset=0):
if node in self.bases:
frame = self.parent.frame()
# line offset to avoid that class A(A) resolve the ancestor to
# the defined class
offset = -1
else:
frame = self
return frame._scope_lookup(node, name, offset)
# list of parent class as a list of string (i.e. names as they appear
# in the class definition) XXX bw compat
def basenames(self):
return [bnode.as_string() for bnode in self.bases]
basenames = property(basenames)
def ancestors(self, recurs=True, context=None):
"""return an iterator on the node base classes in a prefixed
depth first order
:param recurs:
boolean indicating if it should recurse or return direct
ancestors only
"""
# FIXME: should be possible to choose the resolution order
# FIXME: inference make infinite loops possible here
yielded = set([self])
if context is None:
context = InferenceContext()
if sys.version_info[0] >= 3:
if not self.bases and self.qname() != 'builtins.object':
yield builtin_lookup("object")[1][0]
return
for stmt in self.bases:
try:
for baseobj in stmt.infer(context):
if not isinstance(baseobj, Class):
if isinstance(baseobj, Instance):
baseobj = baseobj._proxied
else:
# duh ?
continue
if not baseobj.hide:
if baseobj in yielded:
continue # cf xxx above
yielded.add(baseobj)
yield baseobj
if recurs:
for grandpa in baseobj.ancestors(recurs=True,
context=context):
if grandpa in yielded:
continue # cf xxx above
yielded.add(grandpa)
yield grandpa
except InferenceError:
# XXX log error ?
continue
def local_attr_ancestors(self, name, context=None):
"""return an iterator on astroid representation of parent classes
which have <name> defined in their locals
"""
for astroid in self.ancestors(context=context):
if name in astroid:
yield astroid
def instance_attr_ancestors(self, name, context=None):
"""return an iterator on astroid representation of parent classes
which have <name> defined in their instance attribute dictionary
"""
for astroid in self.ancestors(context=context):
if name in astroid.instance_attrs:
yield astroid
def has_base(self, node):
return node in self.bases
def local_attr(self, name, context=None):
"""return the list of assign node associated to name in this class
locals or in its parents
:raises `NotFoundError`:
if no attribute with this name has been find in this class or
its parent classes
"""
try:
return self.locals[name]
except KeyError:
# get if from the first parent implementing it if any
for class_node in self.local_attr_ancestors(name, context):
return class_node.locals[name]
raise NotFoundError(name)
local_attr = remove_nodes(local_attr, DelAttr)
def instance_attr(self, name, context=None):
"""return the astroid nodes associated to name in this class instance
attributes dictionary and in its parents
:raises `NotFoundError`:
if no attribute with this name has been find in this class or
its parent classes
"""
# Return a copy, so we don't modify self.instance_attrs,
# which could lead to infinite loop.
values = list(self.instance_attrs.get(name, []))
# get all values from parents
for class_node in self.instance_attr_ancestors(name, context):
values += class_node.instance_attrs[name]
if not values:
raise NotFoundError(name)
return values
instance_attr = remove_nodes(instance_attr, DelAttr)
def instanciate_class(self):
"""return Instance of Class node, else return self"""
return Instance(self)
def getattr(self, name, context=None):
"""this method doesn't look in the instance_attrs dictionary since it's
done by an Instance proxy at inference time.
It may return a YES object if the attribute has not been actually
found but a __getattr__ or __getattribute__ method is defined
"""
values = self.locals.get(name, [])
if name in self.special_attributes:
if name == '__module__':
return [cf(self.root().qname())] + values
# FIXME: do we really need the actual list of ancestors?
# returning [Tuple()] + values don't break any test
# this is ticket http://www.logilab.org/ticket/52785
# XXX need proper meta class handling + MRO implementation
if name == '__bases__' or (name == '__mro__' and self.newstyle):
node = Tuple()
node.items = self.ancestors(recurs=True, context=context)
return [node] + values
return std_special_attributes(self, name)
# don't modify the list in self.locals!
values = list(values)
for classnode in self.ancestors(recurs=True, context=context):
values += classnode.locals.get(name, [])
if not values:
raise NotFoundError(name)
return values
def igetattr(self, name, context=None):
"""inferred getattr, need special treatment in class to handle
descriptors
"""
# set lookup name since this is necessary to infer on import nodes for
# instance
if not context:
context = InferenceContext()
try:
for infered in _infer_stmts(self.getattr(name, context), context,
frame=self, lookupname=name):
# yield YES object instead of descriptors when necessary
if not isinstance(infered, Const) and isinstance(infered, Instance):
try:
infered._proxied.getattr('__get__', context)
except NotFoundError:
yield infered
else:
yield YES
else:
yield function_to_method(infered, self)
except NotFoundError:
if not name.startswith('__') and self.has_dynamic_getattr(context):
# class handle some dynamic attributes, return a YES object
yield YES
else:
raise InferenceError(name)
def has_dynamic_getattr(self, context=None):
"""return True if the class has a custom __getattr__ or
__getattribute__ method
"""
# need to explicitly handle optparse.Values (setattr is not detected)
if self.name == 'Values' and self.root().name == 'optparse':
return True
try:
self.getattr('__getattr__', context)
return True
except NotFoundError:
#if self.newstyle: XXX cause an infinite recursion error
try:
getattribute = self.getattr('__getattribute__', context)[0]
if getattribute.root().name != BUILTINS:
# class has a custom __getattribute__ defined
return True
except NotFoundError:
pass
return False
def methods(self):
"""return an iterator on all methods defined in the class and
its ancestors
"""
done = {}
for astroid in chain(iter((self,)), self.ancestors()):
for meth in astroid.mymethods():
if meth.name in done:
continue
done[meth.name] = None
yield meth
def mymethods(self):
"""return an iterator on all methods defined in the class"""
for member in self.values():
if isinstance(member, Function):
yield member
def interfaces(self, herited=True, handler_func=_iface_hdlr):
"""return an iterator on interfaces implemented by the given
class node
"""
# FIXME: what if __implements__ = (MyIFace, MyParent.__implements__)...
try:
implements = Instance(self).getattr('__implements__')[0]
except NotFoundError:
return
if not herited and not implements.frame() is self:
return
found = set()
missing = False
for iface in unpack_infer(implements):
if iface is YES:
missing = True
continue
if not iface in found and handler_func(iface):
found.add(iface)
yield iface
if missing:
raise InferenceError()
_metaclass = None
def _explicit_metaclass(self):
""" Return the explicit defined metaclass
for the current class.
An explicit defined metaclass is defined
either by passing the ``metaclass`` keyword argument
in the class definition line (Python 3) or (Python 2) by
having a ``__metaclass__`` class attribute, or if there are
no explicit bases but there is a global ``__metaclass__`` variable.
"""
for base in self.bases:
try:
for baseobj in base.infer():
if isinstance(baseobj, Class) and baseobj.hide:
self._metaclass = baseobj._metaclass
self._metaclass_hack = True
break
except InferenceError:
pass
if self._metaclass:
# Expects this from Py3k TreeRebuilder
try:
return next(node for node in self._metaclass.infer()
if node is not YES)
except (InferenceError, StopIteration):
return None
if sys.version_info >= (3, ):
return None
if '__metaclass__' in self.locals:
assignment = self.locals['__metaclass__'][-1]
elif self.bases:
return None
elif '__metaclass__' in self.root().locals:
assignments = [ass for ass in self.root().locals['__metaclass__']
if ass.lineno < self.lineno]
if not assignments:
return None
assignment = assignments[-1]
else:
return None
try:
infered = next(assignment.infer())
except InferenceError:
return
if infered is YES: # don't expose this
return None
return infered
def metaclass(self):
""" Return the metaclass of this class.
If this class does not define explicitly a metaclass,
then the first defined metaclass in ancestors will be used
instead.
"""
klass = self._explicit_metaclass()
if klass is None:
for parent in self.ancestors():
klass = parent.metaclass()
if klass is not None:
break
return klass
def has_metaclass_hack(self):
return self._metaclass_hack
def _islots(self):
""" Return an iterator with the inferred slots. """
if '__slots__' not in self.locals:
return
for slots in self.igetattr('__slots__'):
# check if __slots__ is a valid type
for meth in ITER_METHODS:
try:
slots.getattr(meth)
break
except NotFoundError:
continue
else:
continue
if isinstance(slots, Const):
# a string. Ignore the following checks,
# but yield the node, only if it has a value
if slots.value:
yield slots
continue
if not hasattr(slots, 'itered'):
# we can't obtain the values, maybe a .deque?
continue
if isinstance(slots, Dict):
values = [item[0] for item in slots.items]
else:
values = slots.itered()
if values is YES:
continue
for elt in values:
try:
for infered in elt.infer():
if infered is YES:
continue
if (not isinstance(infered, Const) or
not isinstance(infered.value,
six.string_types)):
continue
if not infered.value:
continue
yield infered
except InferenceError:
continue
# Cached, because inferring them all the time is expensive
@cached
def slots(self):
"""Get all the slots for this node.
If the class doesn't define any slot, through `__slots__`
variable, then this function will return a None.
Also, it will return None in the case the slots weren't inferred.
Otherwise, it will return a list of slot names.
"""
slots = self._islots()
try:
first = next(slots)
except StopIteration:
# The class doesn't have a __slots__ definition.
return None
return [first] + list(slots)
def _inferred_bases(self, recurs=True, context=None):
# TODO(cpopa): really similar with .ancestors,
# but the difference is when one base is inferred,
# only the first object is wanted. That's because
# we aren't interested in superclasses, as in the following
# example:
#
# class SomeSuperClass(object): pass
# class SomeClass(SomeSuperClass): pass
# class Test(SomeClass): pass
#
# Inferring SomeClass from the Test's bases will give
# us both SomeClass and SomeSuperClass, but we are interested
# only in SomeClass.
if context is None:
context = InferenceContext()
if sys.version_info[0] >= 3:
if not self.bases and self.qname() != 'builtins.object':
yield builtin_lookup("object")[1][0]
return
for stmt in self.bases:
try:
baseobj = next(stmt.infer(context=context))
except InferenceError:
# XXX log error ?
continue
if isinstance(baseobj, Instance):
baseobj = baseobj._proxied
if not isinstance(baseobj, Class):
continue
if not baseobj.hide:
yield baseobj
def mro(self, context=None):
"""Get the method resolution order, using C3 linearization.
It returns the list of ancestors sorted by the mro.
This will raise `NotImplementedError` for old-style classes, since
they don't have the concept of MRO.
"""
if not self.newstyle:
raise NotImplementedError(
"Could not obtain mro for old-style classes.")
bases = list(self._inferred_bases(context=context))
unmerged_mro = [[self]] + [base.mro() for base in bases] + [bases]
_verify_duplicates_mro(unmerged_mro)
return _c3_merge(unmerged_mro)
Codebase Browser
chromium