diff-quality --options with quotes do not pass to subprocess properly

To reproduce, I created a test branch and touched one long line in a “migrations” directory. I then ran the example given in the docs:

(addgene-core)pam@bento-local:/projects/addgene-core$ diff-quality --violations=pep8 --options="--exclude='*/migrations*' --statistics" pep8_report.txt
No handlers could be found for logger "diff_cover.tool"
-------------
Diff Quality
Quality Report: pep8
Diff: origin/master...HEAD, staged, and unstaged changes
-------------
src/django/lims/tasks/migrations/0001_initial.py (0.0%):
    24: E501 line too long (130 > 79 characters)
-------------
Total:   1 line
Violations: 1 line
% Quality: 0%
-------------

Diff Cover Version:

(addgene-core)pam@bento-local:/projects/addgene-core$ pip freeze | grep diff
diff-cover==0.9.5

My analysis:

1. This is a “hard problem” with passing quotes in arguments to Popen (command_runner.py) I think it would work with “shell=True”, but that entails a number of security concerns.
2. The tests make sure that the “–options” value is parsed from the diff-quality command line (test_args.py), but there is no integration test of an “–options” with embedded quotes (test_integrations.py only tests --options="--violations_test_file.py"

[Bachmann1234]

WOW that got long. Let me TLDR that.

I think the fix would require changes to how diff-quality generates reports that may be good but I am simply not going to get to in the near term.

However, you can work around the issue by generating the report and passing the already completed report to diff-quality. (see example at the end of the giant comment)

[Bachmann1234]

Sorry to be dense but I just tried to reproduce this and failed to (Version 0.9.9)

(venv) ~/Desktop/testProject   repor   pep8 --exclude='*/migrations*,*/vendor*' . > /tmp/pep8-report.txt
(venv) ✘  ~/Desktop/testProject   repor  diff-quality --fail-under=100 --violations=pep8 --compare-branch=master /tmp/pep8-report.txt

-------------
Diff Quality
Quality Report: pep8
Diff: master...HEAD, staged, and unstaged changes
-------------
src/django/addgene/management/commands/giraffe_reanalyze.py (66.7%):
    119: E127 continuation line over-indented for visual indent
    122: E124 closing bracket does not match visual indentation
    136: E222 multiple spaces after operator
-------------
Total:   9 lines
Violations: 3 lines
% Quality: 66%
-------------
Failure. Quality is below 100.0%.

I put the reop here https://github.com/Bachmann1234/diff-cover-issue-50/

The branch I was using is repor