--global-option in requirements.txt doesn't take an effect with pip wheel

[sakurai-youhei]

Environment

• pip version: 18.1
• Python version: 3.7.0, 3.4.3
• OS: Windows 10, Linux

Description

If --global-option is written in requirements.txt (like somepackage --global-option=clean), then pip wheel won't pick up the option.

Case no. 1: --global-option=clean via command line

The clean is inserted before bdist_wheel successfully.

python -m pip -v wheel pip --global-option=clean

  Running command C:\Users\sakurai\Desktop\ENV\Scripts\python.exe -u -c "import setuptools, tokenize;__file__='C:\\Users\\sakurai\\AppData\\Local\\Temp\\pip-wheel-k8cmdetq\\pip\\setup.py';f=getattr(tokenize, 'open', open)(__file__);code=f.read().replace('\r\n', '\n');f.close();exec(compile(code, __file__, 'exec'))" clean bdist_wheel -d C:\Users\sakurai\AppData\Local\Temp\pip-wheel-t40qzaes

Case no. 2: --global-option=clean via requirements.txt

The clean doesn't appear and this is the issue I'd like to report.

echo pip --global-option=clean > requirements.txt
python -m pip -v wheel -r requirements.txt

  Running command C:\Users\sakurai\Desktop\ENV\Scripts\python.exe -u -c "import setuptools, tokenize;__file__='C:\\Users\\sakurai\\AppData\\Local\\Temp\\pip-wheel-s4jol4ag\\pip\\setup.py';f=getattr(tokenize, 'open', open)(__file__);code=f.read().replace('\r\n', '\n');f.close();exec(compile(code, __file__, 'exec'))" bdist_wheel -d C:\Users\sakurai\AppData\Local\Temp\pip-wheel-yq4a_n_u

Expected behavior

Case no. 2 results the same with case no. 1.

Notes

1. I see that --global-option for a specific requirement in requirements file disables use of wheels globally #4118 is apparent in 18.1 but I'm not sure how much they are connected.
2. pip install doesn't seem to have the same issue.
3. 19.0.dev0 would be worse because --global-option=clean does no longer take an effect even if the option is given via command line.