# swegym / python__mypy-10937

- taskset: [swegym](https://harnessreport.com/tasks/swegym.md)
- difficulty: hard
- category: debugging
- language: 
- runnable from the site: no
- agent timeout: 3000s

## Results by harness

_none yet_

## Instruction

```
Cache causes mypy to fail every 2nd run for module importing from aws_cdk
**Bug Report**

When `mypy` is run multiple times on a Python module containing `from aws_cdk import core` it will fail every 2nd time due to the error "Skipping analyzing 'aws_cdk': found module but no type hints or library stubs".

Disabling the mypy cache with `--no-incremental` will result in `mypy` passing every time.

**To Reproduce**

1. Install `mypy` and `aws-cdk.core`.
2. Create a Python module with `from aws_cdk import core`.
3. Run `mypy` on the module and it will pass.
4. Run `mypy` on the module again and it will fail. Subsequent runs will cycle between passing and failing.

```
$ python3.8 -m venv .venv && source .venv/bin/activate
(.venv) $ pip install mypy==0.790 aws-cdk.core==1.80.0
(.venv) $ echo 'from aws_cdk import core' > repro.py
(.venv) $ mypy repro.py
Success: no issues found in 1 source file
(.venv) $ mypy repro.py
repro.py:1: error: Skipping analyzing 'aws_cdk': found module but no type hints or library stubs
repro.py:1: note: See https://mypy.readthedocs.io/en/latest/running_mypy.html#missing-imports
Found 1 error in 1 file (checked 1 source file)
(.venv) $ mypy repro.py
Success: no issues found in 1 source file
(.venv) $ mypy repro.py
repro.py:1: error: Skipping analyzing 'aws_cdk': found module but no type hints or library stubs
repro.py:1: note: See https://mypy.readthedocs.io/en/latest/running_mypy.html#missing-imports
Found 1 error in 1 file (checked 1 source file)
```

**Expected Behavior**

Running `mypy` on a module containing only `from aws_cdk import core` should always pass.

**Actual Behavior**

Every second time `mypy` is run on the module it will report an error.

**Your Environment**

- Mypy version used: 0.790
- Mypy command-line flags: none
- Mypy configuration options from `mypy.ini` (and other config files): none
- Python version used: 3.8.2
- Operating system and version: macOS
- `aws-cdk.core` version used: 1.80.0

The problem may be related to how the package that is installed is `aws-cdk.core` but the namespace being imported from is `aws_cdk`. A workaround is to change:

```python
from aws_cdk import core
```

to:

```python
import aws_cdk.core as core
```

The first form is what is generated by [the `cdk` tool](https://docs.aws.amazon.com/cdk/latest/guide/hello_world.html#hello_world_tutorial_create_app) and used in the cdk [example code](https://github.com/aws-samples/aws-cdk-examples/tree/master/python).
```
---
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