AssertionError with TypedDict and --cache-fine-grained in v1.11.0

[svalentin]

Crash Report

Make a file with:

from typing import TypedDict

class SomeEntry(TypedDict):
    somefield: "set[str]"

Running mypy with --cache-fine-grained causes assertion error.

The assertion error is no longer raised if either of these is done:

• using from __future__ import annotations and changing the types from strings to actual types.
• removing --cache-fine-grained.
• using mypy v1.10.1.

Repro and Traceback

$ python3 -m mypy --strict --cache-fine-grained --show-traceback ~/src/x-play
/home/svalentin/src/x-play/test.py: 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: 1.11.0+dev.d8c67c36d6ecf964dd283de3acffc59d80c8b1fd
Traceback (most recent call last):
  File "/usr/lib/python3.10/runpy.py", line 196, in _run_module_as_main
    return _run_code(code, main_globals, None,
  File "/usr/lib/python3.10/runpy.py", line 86, in _run_code
    exec(code, run_globals)
  File "/home/svalentin/src/mypy/mypy/__main__.py", line 37, in <module>
    console_entry()
  File "/home/svalentin/src/mypy/mypy/__main__.py", line 15, in console_entry
    main()
  File "/home/svalentin/src/mypy/mypy/main.py", line 103, in main
    res, messages, blockers = run_build(sources, options, fscache, t0, stdout, stderr)
  File "/home/svalentin/src/mypy/mypy/main.py", line 187, in run_build
    res = build.build(sources, options, None, flush_errors, fscache, stdout, stderr)
  File "/home/svalentin/src/mypy/mypy/build.py", line 193, in build
    result = _build(
  File "/home/svalentin/src/mypy/mypy/build.py", line 268, in _build
    graph = dispatch(sources, manager, stdout)
  File "/home/svalentin/src/mypy/mypy/build.py", line 2944, in dispatch
    return dispatch(sources, manager, stdout)
  File "/home/svalentin/src/mypy/mypy/build.py", line 2950, in dispatch
    process_graph(graph, manager)
  File "/home/svalentin/src/mypy/mypy/build.py", line 3348, in process_graph
    process_stale_scc(graph, scc, manager)
  File "/home/svalentin/src/mypy/mypy/build.py", line 3453, in process_stale_scc
    graph[id].finish_passes()
  File "/home/svalentin/src/mypy/mypy/build.py", line 2372, in finish_passes
    with self.wrap_context():
  File "/usr/lib/python3.10/contextlib.py", line 153, in __exit__
    self.gen.throw(typ, value, traceback)
  File "/home/svalentin/src/mypy/mypy/build.py", line 2069, in wrap_context
    yield
  File "/home/svalentin/src/mypy/mypy/build.py", line 2409, in finish_passes
    self.update_fine_grained_deps(self.manager.fg_deps)
  File "/home/svalentin/src/mypy/mypy/build.py", line 2467, in update_fine_grained_deps
    merge_dependencies(self.compute_fine_grained_deps(), deps)
  File "/home/svalentin/src/mypy/mypy/build.py", line 2455, in compute_fine_grained_deps
    return get_dependencies(
  File "/home/svalentin/src/mypy/mypy/server/deps.py", line 187, in get_dependencies
    target.accept(visitor)
  File "/home/svalentin/src/mypy/mypy/nodes.py", line 372, in accept
    return visitor.visit_mypy_file(self)
  File "/home/svalentin/src/mypy/mypy/server/deps.py", line 250, in visit_mypy_file
    super().visit_mypy_file(o)
  File "/home/svalentin/src/mypy/mypy/traverser.py", line 116, in visit_mypy_file
    d.accept(self)
  File "/home/svalentin/src/mypy/mypy/nodes.py", line 1183, in accept
    return visitor.visit_class_def(self)
  File "/home/svalentin/src/mypy/mypy/server/deps.py", line 310, in visit_class_def
    super().visit_class_def(o)
  File "/home/svalentin/src/mypy/mypy/traverser.py", line 152, in visit_class_def
    o.defs.accept(self)
  File "/home/svalentin/src/mypy/mypy/nodes.py", line 1264, in accept
    return visitor.visit_block(self)
  File "/home/svalentin/src/mypy/mypy/server/deps.py", line 429, in visit_block
    super().visit_block(o)
  File "/home/svalentin/src/mypy/mypy/traverser.py", line 120, in visit_block
    s.accept(self)
  File "/home/svalentin/src/mypy/mypy/nodes.py", line 1351, in accept
    return visitor.visit_assignment_stmt(self)
  File "/home/svalentin/src/mypy/mypy/server/deps.py", line 490, in visit_assignment_stmt
    self.add_type_dependencies(o.type)
  File "/home/svalentin/src/mypy/mypy/server/deps.py", line 887, in add_type_dependencies
    for trigger in self.get_type_triggers(typ):
  File "/home/svalentin/src/mypy/mypy/server/deps.py", line 940, in get_type_triggers
    return get_type_triggers(typ, self.use_logical_deps())
  File "/home/svalentin/src/mypy/mypy/server/deps.py", line 947, in get_type_triggers
    return typ.accept(TypeTriggersVisitor(use_logical_deps, seen_aliases))
  File "/home/svalentin/src/mypy/mypy/types.py", line 2703, in accept
    assert isinstance(visitor, SyntheticTypeVisitor)
AssertionError:
/home/svalentin/src/x-play/test.py: : note: use --pdb to drop into pdb

Your Environment
Ubuntu 22.04.4 LTS (Jammy Jellyfish)

$ python3 --version
Python 3.10.12
$ python3 -m mypy --version
mypy 1.11.0+dev.d8c67c36d6ecf964dd283de3acffc59d80c8b1fd (compiled: no)

[hauntsaninja]

Writing your example to test.py and adding # flags: --cache-fine-grained --strict then running mypy_primer -p test.py --bisect --debug --old 'v1.10.0' bisects this to #17148 cc @JelleZijlstra

[JelleZijlstra]

Oops. Will take a look though I don't know too much about the cache.

[ilevkivskyi]

This is already fixed on master.

[andersk]

This test case was fixed by e5b3b56 (#17495), but I have another test case that still reproduces the same symptom on current master:

• Another AssertionError with TypedDict and --cache-fine-grained in v1.11.0 #17587