pip 19.3.1 isn't respecting --install-option="--prefix=/install" for some packages

[hmvien]

Environment

• pip version: 19.3.1
• Python version: 3.6
• OS: Linux

Description
When specifying a different install directory using install-option, pip does not install the package into that directory. Currently, I can verify that attrs is not working. I'm not sure if there are other packages with the same issue.

How to Reproduce

bash-5.0# pip install --upgrade pip==19.3.1
bash-5.0# rm -rf /install
bash-5.0# pip install --no-cache-dir --ignore-installed --install-option="--prefix=/install" attrs requests
.....
bash-5.0# ls /install/lib/python3.6/site-packages/
certifi                           chardet                           idna                              requests                          urllib3
certifi-2019.9.11-py3.6.egg-info  chardet-3.0.4-py3.6.egg-info      idna-2.8-py3.6.egg-info           requests-2.22.0-py3.6.egg-info    urllib3-1.25.6-py3.6.egg-info

attrs is missing, but is installed on the system's site-packages instead.

Downgrading to 19.2.3 works as expected

bash-5.0# pip install --upgrade pip==19.2.3
bash-5.0# pip install --no-cache-dir --ignore-installed --install-option="--prefix=/install" -r re^C
bash-5.0# rm -rf /install
bash-5.0# pip install --no-cache-dir --ignore-installed --install-option="--prefix=/install" attrs requests
bash-5.0# ls /install/lib/python3.6/site-packages/
attr                              certifi                           chardet                           idna                              requests                          urllib3
attrs-19.3.0-py3.6.egg-info       certifi-2019.9.11-py3.6.egg-info  chardet-3.0.4-py3.6.egg-info      idna-2.8-py3.6.egg-info           requests-2.22.0-py3.6.egg-info    urllib3-1.25.6-py3.6.egg-info

[chrahunt]

Hi @hmvien. This looks like a duplicate of #7240. Please try installing your packages by passing --prefix=/install to pip itself - internally pip will translate this to --install-option as well as ensure that PEP 517 packages respect the value.

[no-response]

This issue has been automatically closed because there has been no response to our request for more information from the original author. With only the information that is currently in the issue, we don't have enough information to take action. Please reach out if you have or find the answers we need so that we can investigate further.