pip uninstall -r requirements throws an exception if the requirements file contains --install-option

[karlkaebnick]

Environment Versions

OS Type: mac os version 10.15.7
Python version: 3.9.0
pip version: 20.3.3
pip-tools version: 5.5.0

Steps to replicate

• make sure your requirements.txt file has at least one row that contains an install option, e.g., 'arcgis==1.8.2 --install-option="--no-deps"'
• run 'pip uninstall -r requirements.txt' and the exception will be thrown

Expected result

all packages listed in the requirements.txt that are installed should get uninstalled
Actual result

exception is thrown immediately