Files
django-stubs/mypy_django_plugin/transformers/models.py
Maxim Kurnikov 0b1507c81e wip
2020-02-02 03:12:32 +03:00

371 lines
16 KiB
Python

from typing import List, Optional, Type, cast
from django.db.models.base import Model
from django.db.models.fields import DateField, DateTimeField
from django.db.models.fields.related import ForeignKey, OneToOneField
from django.db.models.fields.reverse_related import (
ManyToManyRel, ManyToOneRel, OneToOneRel,
)
from mypy.nodes import (
ARG_STAR2, GDEF, MDEF, Argument, Context, SymbolTableNode, TypeInfo, Var,
)
from mypy.plugin import ClassDefContext
from mypy.plugins import common
from mypy.semanal import SemanticAnalyzer, dummy_context
from mypy.types import AnyType, Instance
from mypy.types import Type as MypyType
from mypy.types import TypeOfAny
from mypy_django_plugin.django.context import DjangoContext
from mypy_django_plugin.lib import fullnames, helpers, sem_helpers
from mypy_django_plugin.transformers import fields
from mypy_django_plugin.transformers.fields import get_field_descriptor_types
class ModelClassInitializer:
api: SemanticAnalyzer
def __init__(self, ctx: ClassDefContext, django_context: DjangoContext):
self.api = cast(SemanticAnalyzer, ctx.api)
self.model_classdef = ctx.cls
self.django_context = django_context
self.ctx = ctx
def lookup_typeinfo(self, fullname: str) -> Optional[TypeInfo]:
return helpers.lookup_fully_qualified_typeinfo(self.api, fullname)
def lookup_typeinfo_or_exception(self, fullname: str) -> TypeInfo:
info = self.lookup_typeinfo(fullname)
if info is None:
raise sem_helpers.IncompleteDefnError(f'No {fullname!r} found')
return info
def lookup_class_typeinfo_or_exception(self, klass: type) -> TypeInfo:
fullname = helpers.get_class_fullname(klass)
field_info = self.lookup_typeinfo_or_exception(fullname)
return field_info
def model_class_has_attribute_defined(self, name: str, traverse_mro: bool = True) -> bool:
if not traverse_mro:
sym = self.model_classdef.info.names.get(name)
else:
sym = self.model_classdef.info.get(name)
return sym is not None
def resolve_manager_fullname(self, manager_fullname: str) -> str:
base_manager_info = self.lookup_typeinfo(fullnames.MANAGER_CLASS_FULLNAME)
if (base_manager_info is None
or 'from_queryset_managers' not in base_manager_info.metadata):
return manager_fullname
metadata = base_manager_info.metadata['from_queryset_managers']
return metadata.get(manager_fullname, manager_fullname)
def add_new_node_to_model_class(self, name: str, typ: MypyType,
force_replace_existing: bool = False) -> None:
if not force_replace_existing and name in self.model_classdef.info.names:
raise ValueError(f'Member {name!r} already defined at model {self.model_classdef.info.fullname!r}.')
var = Var(name, type=typ)
# TypeInfo of the object variable is bound to
var.info = self.model_classdef.info
var._fullname = self.api.qualified_name(name)
var.is_initialized_in_class = True
sym = SymbolTableNode(MDEF, var, plugin_generated=True)
context: Optional[Context] = dummy_context()
if force_replace_existing:
context = None
self.api.add_symbol_table_node(name, sym, context=context)
def add_new_class_for_current_module(self, name: str, bases: List[Instance],
force_replace_existing: bool = False) -> TypeInfo:
current_module = self.api.cur_mod_node
if not force_replace_existing and name in current_module.names:
raise ValueError(f'Class {name!r} already defined for module {current_module.fullname!r}')
new_typeinfo = helpers.new_typeinfo(name,
bases=bases,
module_name=current_module.fullname)
if name in current_module.names:
del current_module.names[name]
current_module.names[name] = SymbolTableNode(GDEF, new_typeinfo, plugin_generated=True)
return new_typeinfo
def run(self) -> None:
model_cls = self.django_context.get_model_class_by_fullname(self.model_classdef.fullname)
if model_cls is None:
return
self.run_with_model_cls(model_cls)
def run_with_model_cls(self, model_cls):
pass
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 = sem_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 AddDefaultPrimaryKey(ModelClassInitializer):
"""
Adds default primary key to models which does not define their own.
```
class User(models.Model):
name = models.TextField()
```
"""
def run_with_model_cls(self, model_cls: Type[Model]) -> None:
auto_field = model_cls._meta.auto_field
if auto_field is None:
return
primary_key_attrname = auto_field.attname
if self.model_class_has_attribute_defined(primary_key_attrname):
return
auto_field_class_fullname = helpers.get_class_fullname(auto_field.__class__)
auto_field_info = self.lookup_typeinfo_or_exception(auto_field_class_fullname)
set_type, get_type = fields.get_field_descriptor_types(auto_field_info, is_nullable=False)
self.add_new_node_to_model_class(primary_key_attrname, Instance(auto_field_info,
[set_type, get_type]))
class AddRelatedModelsId(ModelClassInitializer):
"""
Adds `FIELDNAME_id` attributes to models.
```
class User(models.Model):
pass
class Blog(models.Model):
user = models.ForeignKey(User)
```
`user_id` will be added to `Blog`.
"""
def run_with_model_cls(self, model_cls: Type[Model]) -> None:
for field in model_cls._meta.get_fields():
if not isinstance(field, (OneToOneField, ForeignKey)):
continue
related_id_attr_name = field.attname
if self.model_class_has_attribute_defined(related_id_attr_name):
continue
related_model_cls = self.django_context.get_field_related_model_cls(field)
if related_model_cls is None:
error_context: Context = self.ctx.cls
field_sym = self.ctx.cls.info.get(field.name)
if field_sym is not None and field_sym.node is not None:
error_context = field_sym.node
self.api.fail(f'Cannot find model {field.related_model!r} '
f'referenced in field {field.name!r} ',
ctx=error_context)
self.add_new_node_to_model_class(related_id_attr_name,
AnyType(TypeOfAny.explicit))
continue
if related_model_cls._meta.abstract:
continue
rel_primary_key_field = self.django_context.get_primary_key_field(related_model_cls)
try:
field_info = self.lookup_class_typeinfo_or_exception(rel_primary_key_field.__class__)
except sem_helpers.IncompleteDefnError as exc:
if not self.api.final_iteration:
raise exc
else:
continue
is_nullable = self.django_context.get_field_nullability(field, None)
set_type, get_type = get_field_descriptor_types(field_info, is_nullable)
self.add_new_node_to_model_class(related_id_attr_name,
Instance(field_info, [set_type, get_type]))
class AddManagers(ModelClassInitializer):
def run_with_model_cls(self, model_cls: Type[Model]) -> None:
for manager_name, manager in model_cls._meta.managers_map.items():
if self.model_class_has_attribute_defined(manager_name, traverse_mro=False):
sym = self.model_classdef.info.names.get(manager_name)
assert sym is not None
if (sym.type is not None
and isinstance(sym.type, Instance)
and sym.type.type.has_base(fullnames.BASE_MANAGER_CLASS_FULLNAME)):
# already defined and parametrized properly
continue
if getattr(manager, '_built_with_as_manager', False):
# as_manager is not supported yet
if not self.model_class_has_attribute_defined(manager_name, traverse_mro=True):
self.add_new_node_to_model_class(manager_name, AnyType(TypeOfAny.explicit))
continue
manager_fullname = self.resolve_manager_fullname(helpers.get_class_fullname(manager.__class__))
manager_info = self.lookup_typeinfo_or_exception(manager_fullname)
if manager_name not in self.model_classdef.info.names:
# manager not yet defined, just add models.Manager[ModelName]
manager_type = Instance(manager_info, [Instance(self.model_classdef.info, [])])
self.add_new_node_to_model_class(manager_name, manager_type)
class AddDefaultManagerAttribute(ModelClassInitializer):
def run_with_model_cls(self, model_cls: Type[Model]) -> None:
if self.model_class_has_attribute_defined('_default_manager', traverse_mro=False):
return
if model_cls._meta.default_manager is None:
return
if getattr(model_cls._meta.default_manager, '_built_with_as_manager', False):
self.add_new_node_to_model_class('_default_manager',
AnyType(TypeOfAny.explicit))
return
default_manager_fullname = helpers.get_class_fullname(model_cls._meta.default_manager.__class__)
resolved_default_manager_fullname = self.resolve_manager_fullname(default_manager_fullname)
default_manager_info = self.lookup_typeinfo_or_exception(resolved_default_manager_fullname)
default_manager = Instance(default_manager_info, [Instance(self.model_classdef.info, [])])
self.add_new_node_to_model_class('_default_manager', default_manager)
class AddRelatedManagers(ModelClassInitializer):
def run_with_model_cls(self, model_cls: Type[Model]) -> None:
# add related managers
for relation in self.django_context.get_model_relations(model_cls):
related_manager_attr_name = relation.get_accessor_name()
if related_manager_attr_name is None:
# no reverse accessor
continue
if self.model_class_has_attribute_defined(related_manager_attr_name, traverse_mro=False):
continue
related_model_cls = self.django_context.get_field_related_model_cls(relation)
if related_model_cls is None:
# could not find a referenced model (maybe invalid to= value)
continue
try:
related_model_info = self.lookup_class_typeinfo_or_exception(related_model_cls)
except sem_helpers.IncompleteDefnError as exc:
if not self.api.final_iteration:
raise exc
else:
continue
if isinstance(relation, OneToOneRel):
self.add_new_node_to_model_class(related_manager_attr_name, Instance(related_model_info, []))
continue
if isinstance(relation, (ManyToOneRel, ManyToManyRel)):
try:
related_manager_info = self.lookup_typeinfo_or_exception(
fullnames.RELATED_MANAGER_CLASS) # noqa: E501
if 'objects' not in related_model_info.names:
raise sem_helpers.IncompleteDefnError()
except sem_helpers.IncompleteDefnError as exc:
if not self.api.final_iteration:
raise exc
else:
continue
# create new RelatedManager subclass
parametrized_related_manager_type = Instance(related_manager_info,
[Instance(related_model_info, [])])
default_manager_type = related_model_info.names['objects'].type
if (default_manager_type is None
or not isinstance(default_manager_type, Instance)
or default_manager_type.type.fullname == fullnames.MANAGER_CLASS_FULLNAME):
self.add_new_node_to_model_class(related_manager_attr_name, parametrized_related_manager_type)
continue
name = related_model_cls.__name__ + '_' + 'RelatedManager'
bases = [parametrized_related_manager_type, default_manager_type]
new_related_manager_info = self.add_new_class_for_current_module(name, bases,
force_replace_existing=True)
self.add_new_node_to_model_class(related_manager_attr_name,
Instance(new_related_manager_info, []))
class AddExtraFieldMethods(ModelClassInitializer):
def run_with_model_cls(self, model_cls: Type[Model]) -> None:
# get_FOO_display for choices
for field in self.django_context.get_model_fields(model_cls):
if field.choices:
info = self.lookup_typeinfo_or_exception('builtins.str')
return_type = Instance(info, [])
common.add_method(self.ctx,
name='get_{}_display'.format(field.attname),
args=[],
return_type=return_type)
# get_next_by, get_previous_by for Date, DateTime
for field in self.django_context.get_model_fields(model_cls):
if isinstance(field, (DateField, DateTimeField)) and not field.null:
return_type = Instance(self.model_classdef.info, [])
common.add_method(self.ctx,
name='get_next_by_{}'.format(field.attname),
args=[Argument(Var('kwargs', AnyType(TypeOfAny.explicit)),
AnyType(TypeOfAny.explicit),
initializer=None,
kind=ARG_STAR2)],
return_type=return_type)
common.add_method(self.ctx,
name='get_previous_by_{}'.format(field.attname),
args=[Argument(Var('kwargs', AnyType(TypeOfAny.explicit)),
AnyType(TypeOfAny.explicit),
initializer=None,
kind=ARG_STAR2)],
return_type=return_type)
class AddMetaOptionsAttribute(ModelClassInitializer):
def run_with_model_cls(self, model_cls: Type[Model]) -> None:
if '_meta' not in self.model_classdef.info.names:
options_info = self.lookup_typeinfo_or_exception(fullnames.OPTIONS_CLASS_FULLNAME)
self.add_new_node_to_model_class('_meta',
Instance(options_info, [
Instance(self.model_classdef.info, [])
]))
def process_model_class(ctx: ClassDefContext,
django_context: DjangoContext) -> None:
initializers = [
InjectAnyAsBaseForNestedMeta,
AddDefaultPrimaryKey,
AddRelatedModelsId,
AddManagers,
AddDefaultManagerAttribute,
AddRelatedManagers,
AddExtraFieldMethods,
AddMetaOptionsAttribute,
]
for initializer_cls in initializers:
try:
initializer_cls(ctx, django_context).run()
except sem_helpers.IncompleteDefnError as exc:
if not ctx.api.final_iteration:
ctx.api.defer()
continue
raise exc