dmypy run won't run, prints "Restarting: configuration changed" when ignore_missing_imports = True is configured

[tadeu]

Bug Report

Since at least v0.902, executing dmypy run in a project that has ignore_missing_imports = True in mypy.ini is not working anymore.

To Reproduce

(Write your steps here:)

1. Create src/something.py with some code in it, and create mypy.ini with:

[mypy]
files = src
ignore_missing_imports = True

2. Run dmypy run

Expected Behavior

dmypy run should execute correctly, outputting something like:

Daemon started
src\something.py:1: error: Incompatible types in assignment (expression has type "str", variable has type "int")
Found 1 error in 1 file (checked 26 source files)

Actual Behavior

dmypy run keeps showing:

Restarting: configuration changed
Daemon stopped
Daemon started
Response: {'restart': 'configuration changed', 'platform': 'win32', 'python_version': '3_9', 'roundtrip_time': 0.5543885231018066}

even when trying to run it again.

Your Environment

• Mypy version used: v0.902, v0.910 and 0.920+dev.379622de482ec16dd1676ad6d183dcfca5203194
• Mypy command-line flags: dmypy run
• Mypy configuration options from mypy.ini (and other config files):

[mypy]
files = src
ignore_missing_imports = True

• Python version used: 3.9.5
• Operating system and version: Windows 10 21H1

[tadeu]

I guess it has something to do with these changes: 4642a31#diff-eb09ce67c2059bc9c117d4175e0bd34b1d75bbe8a91c3b9f69a8d14a9c8bc09fR330

[tadeu]

A workaround, for now, is to use this undocumented option together:

ignore_missing_imports_per_module = True

as in:

[mypy]
files = src
ignore_missing_imports = True
ignore_missing_imports_per_module = True

[JukkaL]

I can't reproduce this issue, at least on macOS and Python 3.9.0. Can you provide an example file under src/ that triggers the issue? Also can you try this out in a fresh virtualenv?

[tadeu]

I was trying it in a fresh venv, the source was just a dummy file something.py with

something: int = "something"

Perhaps it's only in Windows? There are some if sys.platform == 'win32': in dmypy :)

[emmatyping]

I can indeed repro this on Windows with the latest mypy in a fresh venv... strange

It also appears the .dmypy.json file sticks around afterwards as well...

[adam-grant-hendry]

It's on my machine on Windows too.

[adam-grant-hendry]

Interestingly, the "temporary" fix does not work if

enable_error_code = ignore-without-code

is also set.

[MartinBernstorff]

I'm getting this same error on windows. The same project works fine on MacOS :-)

[Avasam]

It appears to also be the case with --follow-imports=silent

Edit: nvm [info] dmypy: follow-imports=silent not supported

[ilevkivskyi]

OK, I think I figured it out, Options() object may not equal to itself after a pickle roundtrip (which is what we use to communicate with the daemon on Windows), because of two reasons:

• There is a nontrivial bit of code applied to ignore_missing_imports after upnickling that also sets ignore_missing_imports_per_module
• ErrorCode class doesn't have an __eq__().

The tricky part is that I don't have a Windows machine, but I guess I can tweak Linux code to use Windows logic (and in CI we have Windows).

[ilevkivskyi]

Can someone who has a Windows machine please check if #15429 fixes their issue?