Add separate_packages option

[alex-liang3]

Resolves https://github.com/PyCQA/isort/issues/2104 by adding a separate_packages config option. This should also cover https://github.com/PyCQA/isort/pull/2262.

Sections provided in this field will have the packages within them be separated by a blank line. This also works with custom known_OTHER sections; see tests for examples.

For reference, these changes increase the cyclomatic complexity (PY-R1000) of this function from 68 to 75, so I'm proposing to ignore the check on this function for the same reason as in https://github.com/PyCQA/isort/pull/2340/files#diff-d97e563d18af5b82fdf3bbb340c60da3e6955177a064fcbaf7e8676589933ddaR243

[vavanade]

Any chance of merging this one?

It would really help me. Now I had to write a very ugly hack for the config file to simulate this behavior.

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 99.16%. Comparing base (1157b58) to head (7808f3f).

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #2313   +/-   ##
=======================================
  Coverage   99.16%   99.16%           
=======================================
  Files          40       40           
  Lines        3101     3128   +27     
  Branches      680      687    +7     
=======================================
+ Hits         3075     3102   +27     
  Misses         15       15           
  Partials       11       11           

[alex-liang3]

Thanks for the review @staticdev, and all your efforts on this project so far! I've made the requested changes now, but unfortunately the function call itself still adds +1 to the cyclomatic complexity (the criticality threshold is 50).

Let me know what you think of the changes :)

[lucas-bremond]

Hello @staticdev, I'm also interested in using this feature. Would it be possible to consider merging it?