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Move many to many specific transformer code to a
manytomany.py module
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,144 @@ | ||
| from typing import NamedTuple, Optional, Union | ||
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| from mypy.checker import TypeChecker | ||
| from mypy.nodes import AssignmentStmt, Expression, NameExpr, StrExpr, TypeInfo | ||
| from mypy.plugin import FunctionContext | ||
| from mypy.semanal import SemanticAnalyzer | ||
| from mypy.types import Instance, ProperType, UninhabitedType | ||
| from mypy.types import Type as MypyType | ||
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| from mypy_django_plugin.django.context import DjangoContext | ||
| from mypy_django_plugin.lib import fullnames, helpers | ||
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| class M2MThrough(NamedTuple): | ||
| arg: Optional[Expression] | ||
| model: ProperType | ||
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| class M2MTo(NamedTuple): | ||
| arg: Expression | ||
| model: ProperType | ||
| self: bool # ManyToManyField('self', ...) | ||
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| class M2MArguments(NamedTuple): | ||
| to: M2MTo | ||
| through: Optional[M2MThrough] | ||
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| def fill_model_args_for_many_to_many_field( | ||
| *, | ||
| ctx: FunctionContext, | ||
| model_info: TypeInfo, | ||
| default_return_type: Instance, | ||
| django_context: DjangoContext, | ||
| ) -> Instance: | ||
| if not ctx.args or not ctx.args[0] or len(default_return_type.args) < 2: | ||
| return default_return_type | ||
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| args = get_m2m_arguments(ctx=ctx, model_info=model_info, django_context=django_context) | ||
| if args is None: | ||
| return default_return_type | ||
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| to_arg: MypyType | ||
| if isinstance(default_return_type.args[0], UninhabitedType): | ||
| to_arg = args.to.model | ||
| else: | ||
| # Avoid overwriting a decent 'to' argument | ||
| to_arg = default_return_type.args[0] | ||
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| if isinstance(default_return_type.args[1], UninhabitedType): | ||
| if helpers.is_abstract_model(model_info): | ||
| # Many to many on abstract models doesn't create any implicit, concrete | ||
| # through model, so we populate it with the upper bound to avoid error messages | ||
| through_arg = default_return_type.type.defn.type_vars[1].upper_bound | ||
| elif args.through is None: | ||
| through_arg = default_return_type.args[1] | ||
| else: | ||
| through_arg = args.through.model | ||
| else: | ||
| # Avoid overwriting a decent 'through' argument | ||
| through_arg = default_return_type.args[1] | ||
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| return default_return_type.copy_modified(args=[to_arg, through_arg]) | ||
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| def get_m2m_arguments( | ||
| *, | ||
| ctx: FunctionContext, | ||
| model_info: TypeInfo, | ||
| django_context: DjangoContext, | ||
| ) -> Optional[M2MArguments]: | ||
| checker = helpers.get_typechecker_api(ctx) | ||
| to_arg = ctx.args[0][0] | ||
| to_model: Optional[ProperType] | ||
| if isinstance(to_arg, StrExpr) and to_arg.value == "self": | ||
| to_model = Instance(model_info, []) | ||
| to_self = True | ||
| else: | ||
| to_model = get_model_from_expression(to_arg, api=checker, django_context=django_context) | ||
| to_self = False | ||
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| if to_model is None: | ||
| # 'ManyToManyField()' requires the 'to' argument | ||
| return None | ||
| to = M2MTo(arg=to_arg, model=to_model, self=to_self) | ||
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| through = None | ||
| if len(ctx.args) > 5 and ctx.args[5]: | ||
| # 'ManyToManyField(..., through=)' was called | ||
| through_arg = ctx.args[5][0] | ||
| through_model = get_model_from_expression(through_arg, api=checker, django_context=django_context) | ||
| if through_model is not None: | ||
| through = M2MThrough(arg=through_arg, model=through_model) | ||
| elif not helpers.is_abstract_model(model_info): | ||
| # No explicit 'through' argument was provided and model is concrete. We need | ||
| # to dig up any generated through model for this 'ManyToManyField()' field | ||
| through_arg = None | ||
| m2m_throughs = helpers.get_django_metadata(model_info).get("m2m_throughs", {}) | ||
| if m2m_throughs: | ||
| field_name = None | ||
| for defn in model_info.defn.defs.body: | ||
| if ( | ||
| isinstance(defn, AssignmentStmt) | ||
| and defn.rvalue is ctx.context | ||
| and len(defn.lvalues) == 1 | ||
| and isinstance(defn.lvalues[0], NameExpr) | ||
| ): | ||
| field_name = defn.lvalues[0].name | ||
| break | ||
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| if field_name is not None: | ||
| through_model_fullname = m2m_throughs.get(field_name) | ||
| if through_model_fullname is not None: | ||
| through_model_info = helpers.lookup_fully_qualified_typeinfo(checker, through_model_fullname) | ||
| if through_model_info is not None: | ||
| through = M2MThrough(arg=through_arg, model=Instance(through_model_info, [])) | ||
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| return M2MArguments(to=to, through=through) | ||
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| def get_model_from_expression( | ||
| expr: Expression, | ||
| *, | ||
| api: Union[TypeChecker, SemanticAnalyzer], | ||
| django_context: DjangoContext, | ||
| ) -> Optional[ProperType]: | ||
| """ | ||
| Attempts to resolve an expression to a 'TypeInfo' instance. Any lazy reference | ||
| argument(e.g. "<app_label>.<object_name>") to a Django model is also attempted. | ||
| """ | ||
| # TODO: Handle settings.AUTH_USER_MODEL? | ||
| if isinstance(expr, NameExpr) and isinstance(expr.node, TypeInfo): | ||
| if ( | ||
| expr.node.metaclass_type is not None | ||
| and expr.node.metaclass_type.type.fullname == fullnames.MODEL_METACLASS_FULLNAME | ||
| ): | ||
| return Instance(expr.node, []) | ||
| elif isinstance(expr, StrExpr): | ||
| model_info = helpers.resolve_lazy_reference(expr.value, api=api, django_context=django_context, ctx=expr) | ||
| if model_info is not None: | ||
| return Instance(model_info, []) | ||
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| return None |
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