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# Licensed under the LGPL: https://www.gnu.org/licenses/old-licenses/lgpl-2.1.en.html
# For details: https://github.com/PyCQA/astroid/blob/main/LICENSE
# Copyright (c) https://github.com/PyCQA/astroid/blob/main/CONTRIBUTORS.txt
"""
Astroid hook for the attrs library
Without this hook pylint reports unsupported-assignment-operation
for attrs classes
"""
from astroid.helpers import safe_infer
from astroid.manager import AstroidManager
from astroid.nodes.node_classes import AnnAssign, Assign, AssignName, Call, Unknown
from astroid.nodes.scoped_nodes import ClassDef
ATTRIB_NAMES = frozenset(
("attr.ib", "attrib", "attr.attrib", "attr.field", "attrs.field", "field")
)
ATTRS_NAMES = frozenset(
(
"attr.s",
"attrs",
"attr.attrs",
"attr.attributes",
"attr.define",
"attr.mutable",
"attr.frozen",
"attrs.define",
"attrs.mutable",
"attrs.frozen",
)
)
def is_decorated_with_attrs(node, decorator_names=ATTRS_NAMES) -> bool:
"""Return whether a decorated node has an attr decorator applied."""
if not node.decorators:
return False
for decorator_attribute in node.decorators.nodes:
if isinstance(decorator_attribute, Call): # decorator with arguments
decorator_attribute = decorator_attribute.func
if decorator_attribute.as_string() in decorator_names:
return True
inferred = safe_infer(decorator_attribute)
if inferred and inferred.root().name == "attr._next_gen":
return True
return False
def attr_attributes_transform(node: ClassDef) -> None:
"""Given that the ClassNode has an attr decorator,
rewrite class attributes as instance attributes
"""
# Astroid can't infer this attribute properly
# Prevents https://github.com/PyCQA/pylint/issues/1884
node.locals["__attrs_attrs__"] = [Unknown(parent=node)]
for cdef_body_node in node.body:
if not isinstance(cdef_body_node, (Assign, AnnAssign)):
continue
if isinstance(cdef_body_node.value, Call):
if cdef_body_node.value.func.as_string() not in ATTRIB_NAMES:
continue
else:
continue
targets = (
cdef_body_node.targets
if hasattr(cdef_body_node, "targets")
else [cdef_body_node.target]
)
for target in targets:
rhs_node = Unknown(
lineno=cdef_body_node.lineno,
col_offset=cdef_body_node.col_offset,
parent=cdef_body_node,
)
if isinstance(target, AssignName):
# Could be a subscript if the code analysed is
# i = Optional[str] = ""
# See https://github.com/PyCQA/pylint/issues/4439
node.locals[target.name] = [rhs_node]
node.instance_attrs[target.name] = [rhs_node]
AstroidManager().register_transform(
ClassDef, attr_attributes_transform, is_decorated_with_attrs
)
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