Class TypedDictAnalyzer

mypy/semanal_typeddict.py:62–631

class TypedDictAnalyzer:
    def __init__(
        self, options: Options, api: SemanticAnalyzerInterface, msg: MessageBuilder
    ) -> None:
        self.options = options
        self.api = api
        self.msg = msg

    def analyze_typeddict_classdef(self, defn: ClassDef) -> tuple[bool, TypeInfo | None]:
        """Analyze a class that may define a TypedDict.

        Assume that base classes have been analyzed already.

        Note: Unlike normal classes, we won't create a TypeInfo until
        the whole definition of the TypeDict (including the body and all
        key names and types) is complete.  This is mostly because we
        store the corresponding TypedDictType in the TypeInfo.

        Return (is this a TypedDict, new TypeInfo). Specifics:
         * If we couldn't finish due to incomplete reference anywhere in
           the definition, return (True, None).
         * If this is not a TypedDict, return (False, None).
        """
        possible = False
        for base_expr in defn.base_type_exprs:
            if isinstance(base_expr, CallExpr):
                base_expr = base_expr.callee
            if isinstance(base_expr, IndexExpr):
                base_expr = base_expr.base
            if isinstance(base_expr, RefExpr):
                self.api.accept(base_expr)
                if base_expr.fullname in TPDICT_NAMES or self.is_typeddict(base_expr):
                    possible = True
                    if isinstance(base_expr.node, TypeInfo) and base_expr.node.is_final:
                        err = message_registry.CANNOT_INHERIT_FROM_FINAL
                        self.fail(err.format(base_expr.node.name).value, defn, code=err.code)
        if not possible:
            return False, None
        existing_info = None
        if isinstance(defn.analyzed, TypedDictExpr):
            existing_info = defn.analyzed.info

        field_types: dict[str, Type] | None
        if (
            len(defn.base_type_exprs) == 1
            and isinstance(defn.base_type_exprs[0], RefExpr)
            and defn.base_type_exprs[0].fullname in TPDICT_NAMES
        ):
            # Building a new TypedDict
            field_types, statements, required_keys, readonly_keys = (
                self.analyze_typeddict_classdef_fields(defn)
            )
            if field_types is None:
                return True, None  # Defer
            if self.api.is_func_scope() and "@" not in defn.name:
                defn.name += "@" + str(defn.line)
            info = self.build_typeddict_typeinfo(
                defn.name, field_types, required_keys, readonly_keys, defn.line, existing_info