TypedDict RecursionError

[dmfigol]

• Are you reporting a bug, or opening a feature request?
  Bug
• Please insert below the code you are checking with mypy,
  or a mock-up repro if the source is private. We would appreciate
  if you try to simplify your case to a minimal repro.

from typing import Dict, Any, Optional
from mypy_extensions import TypedDict


VarsDict = Dict[str, Any]
HostsDict = Dict[str, Optional[VarsDict]]

GroupDataDict = TypedDict(
 "GroupDataDict", {"children": "GroupsDict",
 "vars": VarsDict,
 "hosts": HostsDict}, total=False
)

GroupsDict = Dict[str, GroupDataDict]

trying to describe the following data (YAML):

all:
 children:
 servers:
 children:
 webservers:
 hosts:
 foo.example.com:
 bar.example.com:
 dbservers:
 hosts:
 one.example.com:
 two.example.com:
 my_var: from_hostfile
 three.example.com:
 ansible_port: 5555
 ansible_host: 192.0.2.50
 vars:
 some_server: foo.southeast.example.com
 halon_system_timeout: 30
 self_destruct_countdown: 60
 escape_pods: 2
 frontend:
 hosts:
 foo.example.com:

• What is the actual behavior/output?
  Crash
• What is the behavior/output you expect?
  No crash
• What are the versions of mypy and Python you are using?
  0.610 + Python 3.7 / 3.6.6
• Do you see the same issue after installing mypy from Git master?
  Haven't checked
• What are the mypy flags you are using? (For example --strict-optional)

[mypy]
python_version = 3.6

check_untyped_defs = True
disallow_any_generics = True
disallow_untyped_calls = True
ignore_errors = False
ignore_missing_imports = True
strict_optional = True
warn_unused_ignores = True
warn_redundant_casts = True
warn_unused_configs = True

• If mypy crashed with a traceback, please paste
  the full traceback below.

...
 for l in it:
 File "/usr/local/lib/python3.7/site-packages/mypy/types.py", line 1933, in <genexpr>
 return self.strategy(t.accept(self) for t in types)
 File "/usr/local/lib/python3.7/site-packages/mypy/types.py", line 1475, in accept
 return visitor.visit_forwardref_type(self)
 File "/usr/local/lib/python3.7/site-packages/mypy/types.py", line 1921, in visit_forwardref_type
 return t.resolved.accept(self)
 File "/usr/local/lib/python3.7/site-packages/mypy/types.py", line 512, in accept
 return visitor.visit_instance(self)
 File "/usr/local/lib/python3.7/site-packages/mypy/types.py", line 1895, in visit_instance
 return self.query_types(t.args)
 File "/usr/local/lib/python3.7/site-packages/mypy/types.py", line 1933, in query_types
 return self.strategy(t.accept(self) for t in types)
 File "/usr/local/lib/python3.7/site-packages/mypy/typeanal.py", line 990, in combine_lists_strategy
 for l in it:
 File "/usr/local/lib/python3.7/site-packages/mypy/types.py", line 1933, in <genexpr>
 return self.strategy(t.accept(self) for t in types)
 File "/usr/local/lib/python3.7/site-packages/mypy/types.py", line 1103, in accept
 return visitor.visit_typeddict_type(self)
 File "/usr/local/lib/python3.7/site-packages/mypy/types.py", line 1905, in visit_typeddict_type
 return self.query_types(t.items.values())
 File "/usr/local/lib/python3.7/site-packages/mypy/types.py", line 1933, in query_types
 return self.strategy(t.accept(self) for t in types)
 File "/usr/local/lib/python3.7/site-packages/mypy/typeanal.py", line 990, in combine_lists_strategy
 for l in it:
 File "/usr/local/lib/python3.7/site-packages/mypy/types.py", line 1933, in <genexpr>
 return self.strategy(t.accept(self) for t in types)
 File "/usr/local/lib/python3.7/site-packages/mypy/types.py", line 1475, in accept
 return visitor.visit_forwardref_type(self)
 File "/usr/local/lib/python3.7/site-packages/mypy/types.py", line 1921, in visit_forwardref_type
 return t.resolved.accept(self)
 File "/usr/local/lib/python3.7/site-packages/mypy/types.py", line 512, in accept
 return visitor.visit_instance(self)
 File "/usr/local/lib/python3.7/site-packages/mypy/types.py", line 1895, in visit_instance
 return self.query_types(t.args)
RecursionError: maximum recursion depth exceeded

[ilevkivskyi]

My guess this may be a duplicate of #4780 (modulo NamedTuple -> TypedDict). Does the error disappear when you set disallow_any_generics = False?

[dmfigol]

@ilevkivskyi
When i do disallow_any_generics = False, it no longer crashes, but still produces an error:

-> % mypy typeddict-recursion.py
typeddict-recursion.py:8: error: Recursive types not fully supported yet, nested types replaced with "Any"
typeddict-recursion.py:14: error: Recursive types not fully supported yet, nested types replaced with "Any"

[ilevkivskyi]

it no longer crashes, but still produces an error

This is expected (the error explains why). You can just silence it with # type: ignore for now if you accept the risk explained.

[dmfigol]

I understand. I would prefer not to allow any generics.