mypy crashes with "Cannot find component" on subsequent runs

[johnfn]

Crash Report

Running mypy after the first run sometimes crashes.

rm -rf .mypy_cache fixes the issue, but if I then run mypy a few more times, it crashes again.

Traceback

$ mypy
Traceback (most recent call last):
File "/path/to/mypy/mypy", line 8, in <module> sys.exit(console_entry())
File "/path/to/mypy/_-main_-.py",line 15, in console_entry main(
File "mypy/main.py", line 119, in main
File "mypy/main.py"
File "mypy/build.py"
, line 203, in run_build , line 191, in build
File "mypy/build.py", line 267, in _build File "mypy/build.py", line 2937, in dispatch
File "mypy/build.py" , line 3328, in process-graph
File "mypy/build.py",
File '
"mypy/build.py"
line 3409, in process_fresh-modules , line 2107, in fix_cross_refs
File "mypy/fixup.py" , line 52, in fixup-module
File
"mypy/fixup.py" , line 128, in visit_symbol_table
File "mypy/lookup.py", line 49, in lookup_fully_qualified
AssertionError: Cannot find component 'operators' for 'sqlalchemy.sql.operators'

To Reproduce

This is at work, and it's a rather large repo, so I can't provide easy repro steps. I would be happy to provide additional information that you need.

Your Environment

• Mypy version used: v1.15.0
• Mypy command-line flags:
• Mypy configuration options from mypy.ini (and other config files):

[mypy]
mypy_path = server/python_stubs,server

files = server/,test/

explicit_package_bases = True
enable_incomplete_feature=InlineTypedDict

strict = True
warn_return_any = False
disallow_untyped_calls = False
no_implicit_reexport = False
warn_unreachable = True
plugins = pydantic.mypy

Additionally, we added ignore_missing_imports to most of our libraries.

• Python version used:
• python 3.11.11
• Operating system and version:
• macOS ventura

[johnfn]

Here's another one I got just now.

Traceback (most recent call last):
  File "env//bin/mypy", line 8, in <module>
    sys.exit(console_entry())
             ^^^^^^^^^^^^^^^
  File "env/lib/python3.11/site-packages/mypy/__main__.py", line 15, in console_entry
    main()
  File "mypy/main.py", line 119, in main
  File "mypy/main.py", line 203, in run_build
  File "mypy/build.py", line 191, in build
  File "mypy/build.py", line 267, in _build
  File "mypy/build.py", line 2937, in dispatch
  File "mypy/build.py", line 3328, in process_graph
  File "mypy/build.py", line 3409, in process_fresh_modules
  File "mypy/build.py", line 2107, in fix_cross_refs
  File "mypy/fixup.py", line 52, in fixup_module
  File "mypy/fixup.py", line 128, in visit_symbol_table
  File "mypy/lookup.py", line 49, in lookup_fully_qualified
AssertionError: Cannot find component 'attributes' for 'sqlalchemy.orm.attributes'

[colelin26]

Running into the same issue at work

[ilevkivskyi]

Did the crash occur with previous version(s) of mypy? Did you recently update the version of sqlalchemy? (Just trying to understand where to start investigation, issues without repro are 10x harder to fix than issues with a repro).

[johnfn]

I have managed to track this one down. We use sqlalchemy type stubs installed locally + sqlalchemy. It can happen sometimes if you import, say, sqlalchemy.sql.operators, which is defined in sqlalchemy, but the typestubs don't know about sqlalchemy.sql.operators and don't define it.

[Jeitan]

Curious about this since I'm also experiencing daemon crashes since upgrading to mypy 1.15 ... is it related to sqlalchemy specifically? I am using sqlalchemy but I did not recently upgrade the version nor am I using local stubs...

[johnfn]

It's not related to sqlalchemy - the problem happens when you import something which does exist but isn't declared in your typestubs.

[Jeitan]

Ah ok ... thank you!

[mshonichev]

same issue with pydantic_settings 2.9.0:

Traceback (most recent call last):
  File "/home/user/.cache/pypoetry/virtualenvs/packages-WjKhRmAo-py3.11/bin/mypy", line 8, in <module>
    sys.exit(console_entry())
             ^^^^^^^^^^^^^^^
  File "/home/user/.cache/pypoetry/virtualenvs/packages-WjKhRmAo-py3.11/lib/python3.11/site-packages/mypy/__main__.py", line 15, in console_entry
    main()
  File "mypy/main.py", line 119, in main
  File "mypy/main.py", line 203, in run_build
  File "mypy/build.py", line 191, in build
  File "mypy/build.py", line 267, in _build
  File "mypy/build.py", line 2937, in dispatch
  File "mypy/build.py", line 3328, in process_graph
  File "mypy/build.py", line 3409, in process_fresh_modules
  File "mypy/build.py", line 2107, in fix_cross_refs
  File "mypy/fixup.py", line 52, in fixup_module
  File "mypy/fixup.py", line 157, in visit_symbol_table
  File "mypy/fixup.py", line 72, in visit_type_info
  File "mypy/fixup.py", line 159, in visit_symbol_table
  File "mypy/nodes.py", line 1069, in accept
  File "mypy/fixup.py", line 212, in visit_var
  File "mypy/types.py", line 2602, in accept
  File "mypy/fixup.py", line 310, in visit_typeddict_type
  File "mypy/types.py", line 2972, in accept
  File "mypy/fixup.py", line 362, in visit_union_type
  File "mypy/types.py", line 405, in accept
  File "mypy/fixup.py", line 252, in visit_type_alias_type
  File "mypy/fixup.py", line 388, in lookup_fully_qualified_alias
  File "mypy/lookup.py", line 49, in lookup_fully_qualified
AssertionError: Cannot find component 'types' for 'pydantic_settings.sources.types.DotenvType'

environment:

pydantic                                      2.11.3
pydantic-core                                 2.33.1
pydantic-settings                             2.9.0
pydantic-yaml                                 1.4.0
...
mypy                                          1.15.0
mypy-extensions                               1.0.0
...

mypy settings:

[tool.mypy]
python_version = "3.11"
check_untyped_defs = true
show_error_codes = true
warn_unused_configs = true
warn_return_any = true
warn_redundant_casts = true
warn_unused_ignores = true
disallow_untyped_defs = false
disallow_incomplete_defs = true
disallow_untyped_decorators = true
disallow_untyped_calls = true
no_implicit_reexport = true
strict_equality = true
strict_optional = true
explicit_package_bases = true
namespace_packages = true