Crash when **unpacking kwargs typed with a TypedDict into a function typed with ParamSpec in expand_actual_type #16616
Description
Crash Report
This originally occurred when trying to type hint keyword args to a concurrent.Futures.ThreadPoolExecutor.submit. I was able to get it down to a more minimal reproducer. Seems that any kwargs **unpacking where the kwargs are a typed dict can trigger it.
Traceback
mypy ./typed_dict_crash.py --show-traceback
typed_dict_crash.py:37: error: INTERNAL ERROR -- Please try using mypy master on GitHub:
https://mypy.readthedocs.io/en/stable/common_issues.html#using-a-development-mypy-build
Please report a bug at https://github.com/python/mypy/issues
version: 1.8.0+dev.7c33e7c03444ae748b82163e7b4e1666dfaf94c7
Traceback (most recent call last):
File "<frozen runpy>", line 198, in _run_module_as_main
File "<frozen runpy>", line 88, in _run_code
File ".venv\Scripts\mypy.exe\__main__.py", line 7, in <module>
sys.exit(console_entry())
File ".venv\Lib\site-packages\mypy\__main__.py", line 15, in console_entry
main()
File ".venv\Lib\site-packages\mypy\main.py", line 100, in main
res, messages, blockers = run_build(sources, options, fscache, t0, stdout, stderr)
File ".venv\Lib\site-packages\mypy\main.py", line 182, in run_build
res = build.build(sources, options, None, flush_errors, fscache, stdout, stderr)
File ".venv\Lib\site-packages\mypy\build.py", line 191, in build
result = _build(
File ".venv\Lib\site-packages\mypy\build.py", line 265, in _build
graph = dispatch(sources, manager, stdout)
File ".venv\Lib\site-packages\mypy\build.py", line 2943, in dispatch
process_graph(graph, manager)
File ".venv\Lib\site-packages\mypy\build.py", line 3341, in process_graph
process_stale_scc(graph, scc, manager)
File ".venv\Lib\site-packages\mypy\build.py", line 3442, in process_stale_scc
graph[id].type_check_first_pass()
File ".venv\Lib\site-packages\mypy\build.py", line 2311, in type_check_first_pass
self.type_checker().check_first_pass()
File ".venv\Lib\site-packages\mypy\checker.py", line 481, in check_first_pass
self.accept(d)
File ".venv\Lib\site-packages\mypy\checker.py", line 591, in accept
stmt.accept(self)
File ".venv\Lib\site-packages\mypy\nodes.py", line 787, in accept
return visitor.visit_func_def(self)
File ".venv\Lib\site-packages\mypy\checker.py", line 1000, in visit_func_def
self._visit_func_def(defn)
File ".venv\Lib\site-packages\mypy\checker.py", line 1004, in _visit_func_def
self.check_func_item(defn, name=defn.name)
File ".venv\Lib\site-packages\mypy\checker.py", line 1077, in check_func_item
self.check_func_def(defn, typ, name, allow_empty)
File ".venv\Lib\site-packages\mypy\checker.py", line 1293, in check_func_def
self.accept(item.body)
File ".venv\Lib\site-packages\mypy\checker.py", line 591, in accept
stmt.accept(self)
File ".venv\Lib\site-packages\mypy\nodes.py", line 1223, in accept
return visitor.visit_block(self)
File ".venv\Lib\site-packages\mypy\checker.py", line 2770, in visit_block
self.accept(s)
File ".venv\Lib\site-packages\mypy\checker.py", line 591, in accept
stmt.accept(self)
File ".venv\Lib\site-packages\mypy\nodes.py", line 1310, in accept
return visitor.visit_assignment_stmt(self)
File ".venv\Lib\site-packages\mypy\checker.py", line 2818, in visit_assignment_stmt
self.check_assignment(s.lvalues[-1], s.rvalue, s.type is None, s.new_syntax)
File ".venv\Lib\site-packages\mypy\checker.py", line 3026, in check_assignment
rvalue_type = self.expr_checker.accept(rvalue, type_context=type_context)
File ".venv\Lib\site-packages\mypy\checkexpr.py", line 5727, in accept
typ = node.accept(self)
^^^^^^^^^^^^^^^^^
File ".venv\Lib\site-packages\mypy\nodes.py", line 1904, in accept
return visitor.visit_call_expr(self)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File ".venv\Lib\site-packages\mypy\checkexpr.py", line 473, in visit_call_expr
return self.visit_call_expr_inner(e, allow_none_return=allow_none_return)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File ".venv\Lib\site-packages\mypy\checkexpr.py", line 602, in visit_call_expr_inner
ret_type = self.check_call_expr_with_callee_type(
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File ".venv\Lib\site-packages\mypy\checkexpr.py", line 1440, in check_call_expr_with_callee_type
ret_type, callee_type = self.check_call(
^^^^^^^^^^^^^^^^
File ".venv\Lib\site-packages\mypy\checkexpr.py", line 1535, in check_call
return self.check_callable_call(
^^^^^^^^^^^^^^^^^^^^^^^^^
File ".venv\Lib\site-packages\mypy\checkexpr.py", line 1720, in check_callable_call
callee = self.infer_function_type_arguments(
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File ".venv\Lib\site-packages\mypy\checkexpr.py", line 2045, in infer_function_type_arguments
inferred_args, _ = infer_function_type_arguments(
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File ".venv\Lib\site-packages\mypy\infer.py", line 56, in infer_function_type_arguments
constraints = infer_constraints_for_callable(
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File ".venv\Lib\site-packages\mypy\constraints.py", line 226, in infer_constraints_for_callable
actual_type = mapper.expand_actual_type(
^^^^^^^^^^^^^^^^^^^^^^^^^^
File ".venv\Lib\site-packages\mypy\argmap.py", line 248, in expand_actual_type
formal_name = (set(actual_type.items.keys()) - self.kwargs_used).pop()
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
KeyError: 'pop from an empty set'
typed_dict_crash.py:37: : note: use --pdb to drop into pdb
To Reproduce
from typing import Callable, ParamSpec, TypedDict, TypeVar
_T = TypeVar("_T")
_P = ParamSpec("_P")
def submit(__fn: Callable[_P, _T], *args: _P.args, **kwargs: _P.kwargs) -> _T:
"""Similar to concurrent.futures.ThreadPoolExecutor.submit.
https://github.com/python/typeshed/blob/0f7241844eb2692fca8b43994f0e238c50d48d46/stdlib/concurrent/futures/_base.pyi#L51
Minimal stub to repro.
"""
return __fn(*args, **kwargs)
def f(one: str | None = None, **kwargs: str) -> str | None:
print(kwargs)
return one
class D(TypedDict):
"""Keyword args to f."""
one: str
two: str
def func(
typed_dict: D,
) -> None | str:
"""Pass kwargs to an underlying function via a typed dict."""
# Originally this was a concurrent.futures.ThreadPoolExecutor.submit
result = submit(f, **typed_dict)
print(result)
return result
# Both cases will crash
d = D(one="hello", two="world")
submit(f, **d)
func({"one": "hello", "two": "world"})
Your Environment
- Mypy version used: 1.7.1 and current main at
7c33e7c03444ae748b82163e7b4e1666dfaf94c7 - Mypy command-line flags: None
- Mypy configuration options from
mypy.ini(and other config files): None - Python version used: 3.12, 3.11
- Operating system and version: Windows 10