Expose `--no-site-packages` to configuration file.

[alanhdu]

mypy 0.730 currently supports a --no-site-packages flag, which disables searching for PEP561 compliant packages. Unfortunately, it does not seem to be exposed via a configuration file (I did not find it in https://mypy.readthedocs.io/en/latest/config_file.html and several variations in my config file raised an unused config error).

Would it be possible this option configurable via the config file?

[msullivan]

Yeah that is a good idea.

mypy's main.py tracks no-site-packages outside of the main Options object and uses the value to adjust some other options. But it would be simple to make it part of Options and manage it like most of the other options.

Would you like to submit a PR?

[vemel]

As I can see, you can define python_executable in config. So if we change https://github.com/python/mypy/blob/master/mypy/modulefinder.py#L411 to if python_executable:, the following config would work

[mypy]
python_executable=

I do not fully understand the idea behind special-opts as code could easily be rewritten to have just Options namespae, and then every option could be set in mypy.ini

[davidzwa]

@msullivan Me and a colleague are currently involved in finding out how to solve this small issue, as it is marked good-first-issue. It is expected to submit a PR next week.

Currently we found that options.py as well as the config_parser.py have to be adjusted. Is there anything more? Secondly, would you recommend adding a test of some sorts to test our code changes?