stubtest: understand override

[hauntsaninja]

Fixes #18814

[jorenham]

In numtype/tool/stubtest.py I changed line 5 to

#     "mypy[faster-cache] @ git+https://github.com/hauntsaninja/mypy@stubtover",

then ran

uv lock --script tool/stubtest.py --upgrade 

, set show_traceback = true in pyproject.toml, and ran

uv run tool/stubtest.py

which resulted in

      Built numtype @ file:///home/joren/Workspace/numtype
Uninstalled 1 package in 2ms
Installed 1 package in 1ms
python 3.13.2 (main, Feb  7 2025, 04:13:54) [GCC 11.4.0]
numtype 2.2.4.0.dev0 (numpy 2.2.4)

stubtest --mypy-config-file pyproject.toml --allowlist tool/allowlists/common.txt --allowlist tool/allowlists/common-todo.txt --allowlist tool/allowlists/ge-py312.txt numpy
Traceback (most recent call last):
  File "/home/joren/.cache/uv/environments-v2/stubtest-a47cadb5a2d3aac3/bin/stubtest", line 10, in <module>
    sys.exit(main())
  File ".venv/lib/python3.13/site-packages/mypy/stubtest.py", line 2150, in main
    return test_stubs(parse_options(sys.argv[1:]))
  File ".venv/lib/python3.13/site-packages/mypy/stubtest.py", line 2008, in test_stubs
    modules = build_stubs(modules, options, find_submodules=not args.check_typeshed)
  File ".venv/lib/python3.13/site-packages/mypy/stubtest.py", line 1786, in build_stubs
    res = mypy.build.build(sources=sources, options=options)
  File ".venv/lib/python3.13/site-packages/mypy/build.py", line 191, in build
    result = _build(
  File ".venv/lib/python3.13/site-packages/mypy/build.py", line 267, in _build
    graph = dispatch(sources, manager, stdout)
  File ".venv/lib/python3.13/site-packages/mypy/build.py", line 2937, in dispatch
    process_graph(graph, manager)
  File ".venv/lib/python3.13/site-packages/mypy/build.py", line 3335, in process_graph
    process_stale_scc(graph, scc, manager)
  File ".venv/lib/python3.13/site-packages/mypy/build.py", line 3436, in process_stale_scc
    graph[id].type_check_first_pass()
  File ".venv/lib/python3.13/site-packages/mypy/build.py", line 2309, in type_check_first_pass
    self.type_checker().check_first_pass()
  File ".venv/lib/python3.13/site-packages/mypy/checker.py", line 470, in check_first_pass
    self.accept(d)
  File ".venv/lib/python3.13/site-packages/mypy/checker.py", line 576, in accept
    stmt.accept(self)
  File ".venv/lib/python3.13/site-packages/mypy/nodes.py", line 1199, in accept
    return visitor.visit_class_def(self)
  File ".venv/lib/python3.13/site-packages/mypy/checker.py", line 2569, in visit_class_def
    self.accept(defn.defs)
  File ".venv/lib/python3.13/site-packages/mypy/checker.py", line 576, in accept
    stmt.accept(self)
  File ".venv/lib/python3.13/site-packages/mypy/nodes.py", line 1280, in accept
    return visitor.visit_block(self)
  File ".venv/lib/python3.13/site-packages/mypy/checker.py", line 3063, in visit_block
    self.accept(s)
  File ".venv/lib/python3.13/site-packages/mypy/checker.py", line 576, in accept
    stmt.accept(self)
    ~~~~~~~~~~~^^^^^^
  File ".venv/lib/python3.13/site-packages/mypy/nodes.py", line 580, in accept
    return visitor.visit_overloaded_func_def(self)
           ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^^^^^^
  File ".venv/lib/python3.13/site-packages/mypy/checker.py", line 641, in visit_overloaded_func_def
    self._visit_overloaded_func_def(defn)
    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^^^^^^
  File ".venv/lib/python3.13/site-packages/mypy/checker.py", line 697, in _visit_overloaded_func_def
    found_method_base_classes = self.check_method_override(defn)
  File ".venv/lib/python3.13/site-packages/mypy/checker.py", line 2022, in check_method_override
    result = self.check_method_or_accessor_override_for_base(
        defn, base, check_override_compatibility
    )
  File ".venv/lib/python3.13/site-packages/mypy/checker.py", line 2060, in check_method_or_accessor_override_for_base
    if self.check_method_override_for_base_with_name(defn, name, base):
       ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^
  File ".venv/lib/python3.13/site-packages/mypy/checker.py", line 2194, in check_method_override_for_base_with_name
    self.check_setter_type_override(defn, base_attr, base)
    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^
  File ".venv/lib/python3.13/site-packages/mypy/checker.py", line 2084, in check_setter_type_override
    original_type, is_original_setter = get_raw_setter_type(base_node)
                                        ~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^
  File ".venv/lib/python3.13/site-packages/mypy/checker.py", line 8919, in get_raw_setter_type
    assert var.type is not None
           ^^^^^^^^^^^^^^^^^^^^
AssertionError: 
src/numpy-stubs/ma/core.pyi:309: 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: 1.16.0+dev.73e19e32d426f15bb97c4877c8bcc73c96c549ab
src/numpy-stubs/ma/core.pyi:309: : note: use --pdb to drop into pdb

---

This looks like the same crash from before that I thought was fixed. Maybe your branch isn't up to date with master or something?

[jorenham]

I created https://github.com/numpy/numtype/tree/mypy-18814 with the repro of the issue and the modifications from #18815 (comment)

From there, you can uv run --reinstall --upgrade tool/stubtest.py (no need to worry about lockfiles)

[hauntsaninja]

Okay cool, in the light of day, I have confirmed this fixes the crash. (I did need to move one or two type ignores around when rebased on top of latest). Thanks for the report/repro!

[jorenham]

Thanks again for the quick fix @hauntsaninja 💪🏻