# copyright 2003-2013 LOGILAB S.A. (Paris, FRANCE), all rights reserved.
# contact http://www.logilab.fr/ -- mailto:contact@logilab.fr
#
# 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 .
"""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, MroError,
DuplicateBasesError, InconsistentMroError,
)
from astroid.node_classes import (
Const, DelName, DelAttr,
Dict, From, List, Pass, Raise, Return, Tuple, Yield, YieldFrom,
LookupMixIn, const_factory as cf, unpack_infer, CallFunc,
)
from astroid.bases import (
NodeNG, InferenceContext, Instance, copy_context,
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 InconsistentMroError(
"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 DuplicateBasesError('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 in locals ( 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)
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
context = copy_context(context)
context.lookupname = name
try:
return _infer_stmts(self.getattr(name, context), context, frame=self)
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 = ''
# 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
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():
result = Generator()
result.parent = self
yield result
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
bases = [next(b.infer(context)) for b in caller.args[1:]]
c.bases = [base for base in bases if base != YES]
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():
baseobj_name = baseobj.qname()
if baseobj_name in seen:
continue
else:
seen.add(baseobj_name)
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 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('Exception'):
klass._type = 'exception'
else:
if ancestors is None:
ancestors = set()
klass_name = klass.qname()
if klass_name in ancestors:
# XXX we are in loop ancestors, and have found no type
klass._type = 'class'
return 'class'
ancestors.add(klass_name)
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__'))
_type = None
_metaclass_hack = False
hide = False
type = property(_class_type,
doc="class'type, possible values are 'class' | "
"'metaclass' | '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_type_call(self, caller, context):
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:
return YES
result = Class(name, None)
# Get the bases of the class.
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.
return YES
# Get the members of the class
try:
members = next(caller.args[2].infer(context))
except InferenceError:
members = None
if members and isinstance(members, Dict):
for attr, value in members.items:
if (isinstance(attr, Const) and
isinstance(attr.value, six.string_types)):
result.locals[attr.value] = [value]
result.parent = caller.parent
return result
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):
result = self._infer_type_call(caller, context)
yield result
else:
yield Instance(self)
def scope_lookup(self, node, name, offset=0):
if any(node == base or base.parent_of(node)
for base in self.bases):
# Handle the case where we have either a name
# in the bases of a class, which exists before
# the actual definition or the case where we have
# a Getattr node, with that name.
#
# name = ...
# class A(name):
# def name(self): ...
#
# import name
# class A(name.Name):
# def name(self): ...
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:
with context.restore_path():
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 is self:
# This class is the ancestor of itself.
break
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 defined in their locals
"""
if self.newstyle and all(n.newstyle for n in self.ancestors(context)):
# Look up in the mro if we can. This will result in the
# attribute being looked up just as Python does it.
try:
ancestors = self.mro(context)[1:]
except MroError:
# Fallback to use ancestors, we can't determine
# a sane MRO.
ancestors = self.ancestors(context=context)
else:
ancestors = self.ancestors(context=context)
for astroid in ancestors:
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 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:
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
context = copy_context(context)
context.lookupname = name
try:
for infered in _infer_stmts(self.getattr(name, context), context,
frame=self):
# 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):
"""
Check if the current instance has a custom __getattr__
or a custom __getattribute__.
If any such method is found and it is not from
builtins, nor from an extension module, then the function
will return True.
"""
def _valid_getattr(node):
root = node.root()
return root.name != BUILTINS and getattr(root, 'pure_python', None)
try:
return _valid_getattr(self.getattr('__getattr__', context)[0])
except NotFoundError:
#if self.newstyle: XXX cause an infinite recursion error
try:
getattribute = self.getattr('__getattribute__', context)[0]
return _valid_getattr(getattribute)
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()
def implicit_metaclass(self):
"""Get the implicit metaclass of the current class
For newstyle classes, this will return an instance of builtins.type.
For oldstyle classes, it will simply return None, since there's
no implicit metaclass there.
"""
if self.newstyle:
return builtin_lookup('type')[1][0]
_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
if not values:
# Stop the iteration, because the class
# has an empty list of slots.
raise StopIteration(values)
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.
"""
if not self.newstyle:
raise NotImplementedError(
"The concept of slots is undefined for old-style classes.")
slots = self._islots()
try:
first = next(slots)
except StopIteration as exc:
# The class doesn't have a __slots__ definition or empty slots.
if exc.args and exc.args[0] not in ('', None):
return exc.args[0]
return None
return [first] + list(slots)
def _inferred_bases(self, 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
else:
for base in baseobj.bases:
yield base
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))
bases_mro = []
for base in bases:
try:
mro = base.mro(context=context)
bases_mro.append(mro)
except NotImplementedError:
# Some classes have in their ancestors both newstyle and
# old style classes. For these we can't retrieve the .mro,
# although in Python it's possible, since the class we are
# currently working is in fact new style.
# So, we fallback to ancestors here.
ancestors = list(base.ancestors(context=context))
bases_mro.append(ancestors)
unmerged_mro = ([[self]] + bases_mro + [bases])
_verify_duplicates_mro(unmerged_mro)
return _c3_merge(unmerged_mro)