diff options
Diffstat (limited to 'Lib/typing.py')
| -rw-r--r-- | Lib/typing.py | 31 |
1 files changed, 30 insertions, 1 deletions
diff --git a/Lib/typing.py b/Lib/typing.py index 4636798..26c6b8c 100644 --- a/Lib/typing.py +++ b/Lib/typing.py @@ -126,6 +126,7 @@ __all__ = [ 'get_origin', 'get_type_hints', 'is_typeddict', + 'LiteralString', 'Never', 'NewType', 'no_type_check', @@ -180,7 +181,7 @@ def _type_check(arg, msg, is_argument=True, module=None, *, allow_special_forms= if (isinstance(arg, _GenericAlias) and arg.__origin__ in invalid_generic_forms): raise TypeError(f"{arg} is not valid as type argument") - if arg in (Any, NoReturn, Never, Self, TypeAlias): + if arg in (Any, LiteralString, NoReturn, Never, Self, TypeAlias): return arg if allow_special_forms and arg in (ClassVar, Final): return arg @@ -524,6 +525,34 @@ def Self(self, parameters): @_SpecialForm +def LiteralString(self, parameters): + """Represents an arbitrary literal string. + + Example:: + + from typing import LiteralString + + def run_query(sql: LiteralString) -> ... + ... + + def caller(arbitrary_string: str, literal_string: LiteralString) -> None: + run_query("SELECT * FROM students") # ok + run_query(literal_string) # ok + run_query("SELECT * FROM " + literal_string) # ok + run_query(arbitrary_string) # type checker error + run_query( # type checker error + f"SELECT * FROM students WHERE name = {arbitrary_string}" + ) + + Only string literals and other LiteralStrings are compatible + with LiteralString. This provides a tool to help prevent + security issues such as SQL injection. + + """ + raise TypeError(f"{self} is not subscriptable") + + +@_SpecialForm def ClassVar(self, parameters): """Special type construct to mark class variables. |