Adds length_sort_straight option

[sztamas]

Does this look OK as a solution to resolve #1232?

Added a new option that length sorts just the straight imports. It is off by default.
See it in action below with the examples of the OP:

▶ cat t.py            
from datetime import timedelta
from contextlib import ExitStack

import os
import datetime
import sys

▶ poetry run isort -d t.py --length-sort-straight
import os
import sys
import datetime
from contextlib import ExitStack
from datetime import timedelta

[sztamas]

Fixed this test as os and sys sort the same in both alphabetical and length sort mode. Added datetime that would be first in alphabetical, but last in length sort mode.

[codecov-commenter]

Codecov Report

Merging #1373 into develop will not change coverage.
The diff coverage is 100.00%.

@@            Coverage Diff            @@
##           develop     #1373   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
=========================================
  Files           36        36           
  Lines         2475      2477    +2     
=========================================
+ Hits          2475      2477    +2     

[timothycrosley]

This looks like a great solution to me! Simple, effective, and solves the ask completely.

Thank you!

[warsaw]

Looks great to me too[*], thank you!

[*] With a blank line between the straights and the froms.

[timothycrosley]

@warsaw to get a blank line between the two this can be combined with the lines-between-types option in isort 5.4.0+:

Example based on above:

isort -d t.py --length-sort-straight --lines-between-types 1

[warsaw]

It's exactly what I want. I'm ecstatic! Here's my setup.cfg for isort:

[tool:isort]
length_sort_straight = true
lines_after_imports = 2
lines_between_types = 1
multi_line_output = 4
order_by_type = false
skip = conf.py
known_first_party = flufl

You rock @timothycrosley Thank you!

[warsaw]

https://gitlab.com/warsaw/flufl.lock/-/merge_requests/29/diffs