Change dmypy status file with config or environment variable

[christianbundy]

Feature

The only way I've been able to set the dmypy status file is by passing --status-file on the command-line, but I'm running dmypy in a few different scripts and would love to be able to hard-code this in one spot.

Pitch

Instead of dmypy --status-file /tmp/dmypy-status, I'd like to either make an environment variable (DMYPY_STATUS_FILE, DMYPY_STATUS_FILE, or similar) or even a mypy config option (status_file?) so that I don't have to explicitly set the status file in every command-line invocation.

Why are you even changing the status file?

Great question. I'm using Docker with a host-mounted volume, and I'd like to avoid sharing the host-mounted volume back and forth between the host and the container. By moving it out of the current directory, I'll be able to run dmypy both inside and outside of the container without conflicts.