Bug Report

First of all, thank you for supporting the highly requested pyproject.toml config format #5205

I'm hoping we can resolve an issue to bring mypy inline with several others including but not limited to isort, black, and pylint. I think mypy should search parent directories for pyproject.toml config file. I think mypy should search up until the user's home directory (or ~25 directories, whichever comes first) for config files.

To Reproduce

Prepare a project such as this

outer/
    inner/
        main.py
    pyproject.toml

From inside the inner directory, run mypy main.py

Expected Behavior

I expect mypy to use the settings defined in the pyproject.toml file found in the parent directory outer. I'm guessing mypy only checks the directory it is invoked from.

Actual Behavior

The settings inside pyproject.toml are not used.

Your Environment

• Mypy version used: 0.900
• Mypy command-line flags: None
• Mypy configuration options from mypy.ini (and other config files): None
• Python version used: 3.9.4
• Operating system and version: macOS 10.15