Files
django-stubs/mypy_django_plugin/transformers/models.py
Maxim Kurnikov b11a9a85f9 new semanal wip 1
2019-07-24 13:38:49 +03:00

389 lines
18 KiB
Python

from abc import ABCMeta, abstractmethod
from typing import Any, Dict, Iterator, List, Optional, Tuple, cast
import dataclasses
from mypy.nodes import (
ARG_POS, ARG_STAR, ARG_STAR2, MDEF, Argument, CallExpr, ClassDef, Expression, IndexExpr, MemberExpr, MypyFile,
NameExpr, StrExpr, SymbolTableNode, TypeInfo, Var,
)
from mypy.plugin import ClassDefContext
from mypy.plugins.common import add_method
from mypy.semanal import SemanticAnalyzerPass2
from mypy.types import AnyType, Instance, NoneTyp, TypeOfAny
from mypy_django_plugin.lib import metadata, fullnames, helpers
@dataclasses.dataclass
class ModelClassInitializer(metaclass=ABCMeta):
api: SemanticAnalyzerPass2
model_classdef: ClassDef
app_models_mapping: Optional[Dict[str, str]] = None
@classmethod
def from_ctx(cls, ctx: ClassDefContext, app_models_mapping: Optional[Dict[str, str]]):
return cls(api=cast(SemanticAnalyzerPass2, ctx.api),
model_classdef=ctx.cls,
app_models_mapping=app_models_mapping)
def get_meta_attribute(self, name: str) -> Optional[Expression]:
meta_node = helpers.get_nested_meta_node_for_current_class(self.model_classdef.info)
if meta_node is None:
return None
return helpers.get_assignment_stmt_by_name(meta_node, name)
def is_abstract_model(self) -> bool:
is_abstract_expr = self.get_meta_attribute('abstract')
if is_abstract_expr is None:
return False
return self.api.parse_bool(is_abstract_expr)
def add_new_node_to_model_class(self, name: str, typ: Instance) -> None:
# type=: type of the variable itself
var = Var(name=name, type=typ)
# var.info: type of the object variable is bound to
var.info = self.model_classdef.info
var._fullname = self.model_classdef.info.fullname() + '.' + name
var.is_inferred = True
var.is_initialized_in_class = True
self.model_classdef.info.names[name] = SymbolTableNode(MDEF, var, plugin_generated=True)
def model_has_name_defined(self, name: str) -> bool:
return name in self.model_classdef.info.names
@abstractmethod
def run(self) -> None:
raise NotImplementedError()
def iter_over_one_to_n_related_fields(klass: ClassDef) -> Iterator[Tuple[NameExpr, CallExpr]]:
for field_name, field_init in helpers.iter_over_field_inits_in_class(klass):
field_info = field_init.callee.node
assert isinstance(field_info, TypeInfo)
if helpers.has_any_of_bases(field_init.callee.node, {fullnames.FOREIGN_KEY_FULLNAME,
fullnames.ONETOONE_FIELD_FULLNAME}):
yield field_name, field_init
class AddReferencesToRelatedModels(ModelClassInitializer):
"""
For every
attr1 = models.ForeignKey(to=MyModel)
sets `attr1_id` attribute to the current model.
"""
def run(self) -> None:
for field_name, field_init_expr in helpers.iter_over_field_inits_in_class(self.model_classdef):
ref_id_name = field_name + '_id'
field_info = field_init_expr.callee.node
assert isinstance(field_info, TypeInfo)
if not self.model_has_name_defined(ref_id_name):
if helpers.has_any_of_bases(field_info, {fullnames.FOREIGN_KEY_FULLNAME,
fullnames.ONETOONE_FIELD_FULLNAME}):
self.add_new_node_to_model_class(name=ref_id_name,
typ=self.api.builtin_type('builtins.int'))
# field_init_expr.callee.node
#
# for field_name, field_init_expr in helpers.iter_call_assignments_in_class(self.model_classdef):
# ref_id_name = field_name + '_id'
# if not self.model_has_name_defined(ref_id_name):
# field_class_info = field_init_expr.callee.node
# if not field_class_info:
#
# if not field_init_expr.callee.node:
#
# if isinstance(field_init_expr.callee.node, TypeInfo) \
# and helpers.has_any_of_bases(field_init_expr.callee.node,
# {fullnames.FOREIGN_KEY_FULLNAME,
# fullnames.ONETOONE_FIELD_FULLNAME}):
# self.add_new_node_to_model_class(name=ref_id_name,
# typ=self.api.builtin_type('builtins.int'))
class InjectAnyAsBaseForNestedMeta(ModelClassInitializer):
"""
Replaces
class MyModel(models.Model):
class Meta:
pass
with
class MyModel(models.Model):
class Meta(Any):
pass
to get around incompatible Meta inner classes for different models.
"""
def run(self) -> None:
meta_node = helpers.get_nested_meta_node_for_current_class(self.model_classdef.info)
if meta_node is None:
return None
meta_node.fallback_to_any = True
class AddDefaultObjectsManager(ModelClassInitializer):
def _add_new_manager(self, name: str, manager_type: Optional[Instance]) -> None:
if manager_type is None:
return None
self.add_new_node_to_model_class(name, manager_type)
def _add_private_default_manager(self, manager_type: Optional[Instance]) -> None:
if manager_type is None:
return None
self.add_new_node_to_model_class('_default_manager', manager_type)
def _get_existing_managers(self) -> List[Tuple[str, TypeInfo]]:
managers = []
for base in self.model_classdef.info.mro:
for manager_name, call_expr in helpers.iter_call_assignments_in_class(base.defn):
callee_expr = call_expr.callee
if isinstance(callee_expr, IndexExpr):
callee_expr = callee_expr.analyzed.expr
if isinstance(callee_expr, (MemberExpr, NameExpr)) \
and isinstance(callee_expr.node, TypeInfo) \
and callee_expr.node.has_base(fullnames.BASE_MANAGER_CLASS_FULLNAME):
managers.append((manager_name, callee_expr.node))
return managers
def run(self) -> None:
existing_managers = self._get_existing_managers()
if existing_managers:
first_manager_type = None
for manager_name, manager_type_info in existing_managers:
manager_type = Instance(manager_type_info, args=[Instance(self.model_classdef.info, [])])
self._add_new_manager(name=manager_name, manager_type=manager_type)
if first_manager_type is None:
first_manager_type = manager_type
else:
if self.is_abstract_model():
# abstract models do not need 'objects' queryset
return None
first_manager_type = self.api.named_type_or_none(fullnames.MANAGER_CLASS_FULLNAME,
args=[Instance(self.model_classdef.info, [])])
self._add_new_manager('objects', manager_type=first_manager_type)
if self.is_abstract_model():
return None
default_manager_name_expr = self.get_meta_attribute('default_manager_name')
if isinstance(default_manager_name_expr, StrExpr):
self._add_private_default_manager(self.model_classdef.info.get(default_manager_name_expr.value).type)
else:
self._add_private_default_manager(first_manager_type)
class AddDefaultPrimaryKey(ModelClassInitializer):
"""
Sets default integer `id` attribute, if:
* model is not abstract (abstract = False)
* there's no field with primary_key=True
"""
def run(self) -> None:
if self.is_abstract_model():
# abstract models cannot be instantiated, and do not need `id` attribute
return None
for _, field_init_expr in helpers.iter_over_field_inits_in_class(self.model_classdef):
if ('primary_key' in field_init_expr.arg_names
and self.api.parse_bool(field_init_expr.args[field_init_expr.arg_names.index('primary_key')])):
break
else:
self.add_new_node_to_model_class('id', self.api.builtin_type('builtins.int'))
def _get_to_expr(field_init_expr) -> Expression:
if 'to' in field_init_expr.arg_names:
return field_init_expr.args[field_init_expr.arg_names.index('to')]
else:
return field_init_expr.args[0]
class AddRelatedManagers(ModelClassInitializer):
def _add_related_manager_variable(self, manager_name: str, related_field_type_data: Dict[str, Any]) -> None:
# add dummy related manager for use later
self.add_new_node_to_model_class(manager_name, self.api.builtin_type('builtins.object'))
# save name in metadata for use in get_attribute_hook later
related_managers_metadata = metadata.get_related_managers_metadata(self.model_classdef.info)
related_managers_metadata[manager_name] = related_field_type_data
def run(self) -> None:
for module_name, module_file in self.api.modules.items():
for model_classdef in helpers.iter_over_toplevel_classes(module_file):
for field_name, field_init in helpers.iter_over_field_inits_in_class(model_classdef):
field_info = field_init.callee.node
assert isinstance(field_info, TypeInfo)
if helpers.has_any_of_bases(field_info, fullnames.RELATED_FIELDS_CLASSES):
# try:
to_arg_expr = _get_to_expr(field_init)
if isinstance(to_arg_expr, NameExpr):
referenced_model_fullname = module_file.names[to_arg_expr.name].fullname
else:
assert isinstance(to_arg_expr, StrExpr)
value = to_arg_expr.value
if value == 'self':
# reference to the same model class
referenced_model_fullname = model_classdef.fullname
elif '.' not in value:
# reference to class in the current module
referenced_model_fullname = module_name + '.' + value
else:
referenced_model_fullname = self.app_models_mapping[value]
# referenced_model_fullname = extract_referenced_model_fullname(field_init,
# module_file=module_file,
# all_modules=self.api.modules)
# if not referenced_model_fullname:
# raise helpers.IncompleteDefnException('Cannot parse referenced model fullname')
# except helpers.SelfReference:
# referenced_model_fullname = model_classdef.fullname
#
# except helpers.SameFileModel as exc:
# referenced_model_fullname = module_name + '.' + exc.model_cls_name
if self.model_classdef.fullname == referenced_model_fullname:
if 'related_name' in field_init.arg_names:
related_name_expr = field_init.args[field_init.arg_names.index('related_name')]
if not isinstance(related_name_expr, StrExpr):
# not string 'related_name=' not yet supported
continue
related_name = related_name_expr.value
if related_name == '+':
# No backwards relation is desired
continue
else:
related_name = model_classdef.name.lower() + '_set'
# Default related_query_name to related_name
if 'related_query_name' in field_init.arg_names:
related_query_name_expr = field_init.args[field_init.arg_names.index('related_query_name')]
if isinstance(related_query_name_expr, StrExpr):
related_query_name = related_query_name_expr.value
else:
# not string 'related_query_name=' is not yet supported
related_query_name = None
# TODO: Handle defaulting to model name if related_name is not set
else:
related_query_name = related_name
# if helpers.has_any_of_bases(field_info, {fullnames.FOREIGN_KEY_FULLNAME,
# fullnames.MANYTOMANY_FIELD_FULLNAME}):
# # as long as Model is not a Generic, one level depth is fine
# field_type_data = {
# 'manager': fullnames.RELATED_MANAGER_CLASS_FULLNAME,
# 'of': [model_classdef.info.fullname()]
# }
# else:
# field_type_data = {
# 'manager': model_classdef.info.fullname(),
# 'of': []
# }
self.add_new_node_to_model_class(related_name, self.api.builtin_type('builtins.object'))
# self._add_related_manager_variable(related_name, related_field_type_data=field_type_data)
if related_query_name is not None:
# Only create related_query_name if it is a string literal
metadata.get_lookups_metadata(self.model_classdef.info)[related_query_name] = {
'related_query_name_target': related_name
}
def get_related_field_type(rvalue: CallExpr, related_model_typ: TypeInfo) -> Dict[str, Any]:
if rvalue.callee.name in {'ForeignKey', 'ManyToManyField'}:
return {
'manager': fullnames.RELATED_MANAGER_CLASS_FULLNAME,
'of': [related_model_typ.fullname()]
}
else:
return {
'manager': related_model_typ.fullname(),
'of': []
}
def is_related_field(expr: CallExpr, module_file: MypyFile) -> bool:
""" Checks whether current CallExpr represents any supported RelatedField subclass"""
if isinstance(expr.callee, MemberExpr) and isinstance(expr.callee.expr, NameExpr):
module = module_file.names.get(expr.callee.expr.name)
if module \
and module.fullname == 'django.db.models' \
and expr.callee.name in {'ForeignKey',
'OneToOneField',
'ManyToManyField'}:
return True
return False
def extract_referenced_model_fullname(field_init_expr: CallExpr,
module_file: MypyFile,
all_modules: Dict[str, MypyFile]) -> Optional[str]:
""" Returns fullname of a Model referenced in "to=" argument of the CallExpr"""
if 'to' in field_init_expr.arg_names:
to_expr = field_init_expr.args[field_init_expr.arg_names.index('to')]
else:
to_expr = field_init_expr.args[0]
if isinstance(to_expr, NameExpr):
return module_file.names[to_expr.name].fullname
elif isinstance(to_expr, StrExpr):
typ_fullname = helpers.get_model_fullname_from_string(to_expr.value, all_modules)
if typ_fullname is None:
return None
return typ_fullname
return None
def add_dummy_init_method(ctx: ClassDefContext) -> None:
any = AnyType(TypeOfAny.special_form)
pos_arg = Argument(variable=Var('args', any),
type_annotation=any, initializer=None, kind=ARG_STAR)
kw_arg = Argument(variable=Var('kwargs', any),
type_annotation=any, initializer=None, kind=ARG_STAR2)
add_method(ctx, '__init__', [pos_arg, kw_arg], NoneTyp())
# mark as model class
ctx.cls.info.metadata.setdefault('django', {})['generated_init'] = True
def add_get_set_attr_fallback_to_any(ctx: ClassDefContext):
any = AnyType(TypeOfAny.special_form)
name_arg = Argument(variable=Var('name', any),
type_annotation=any, initializer=None, kind=ARG_POS)
add_method(ctx, '__getattr__', [name_arg], any)
value_arg = Argument(variable=Var('value', any),
type_annotation=any, initializer=None, kind=ARG_POS)
add_method(ctx, '__setattr__', [name_arg, value_arg], any)
def process_model_class(ctx: ClassDefContext,
ignore_unknown_attributes: bool,
app_models_mapping: Optional[Dict[str, str]]) -> None:
initializers = [
InjectAnyAsBaseForNestedMeta,
AddDefaultPrimaryKey,
AddReferencesToRelatedModels,
AddDefaultObjectsManager,
AddRelatedManagers,
]
for initializer_cls in initializers:
initializer_cls.from_ctx(ctx, app_models_mapping).run()
add_dummy_init_method(ctx)
if ignore_unknown_attributes:
add_get_set_attr_fallback_to_any(ctx)