Check install path

[tfolbrecht]

Enhancement proposal:

issue #6762

Before

if a user runs pip install without write access to the target directory, it will collect and download packages before failing with permission denied.

After

This PR uses the check_path_owner function from pip._internal.utils.filesystem to check write permissions and exits with an error message

I'm still learning python.
If it would be better to move the option checks to a function I'll close this and go ahead and do that.

Thank you for taking the time to review my PR.

[pradyunsg]

@tfolbrecht You don't need to close the PR -- you can just push more commits to the same branch. :)

[pradyunsg]

Here is an old, but relevant article about pull requests: https://yangsu.github.io/pull-request-tutorial/ :)

[tfolbrecht]

Thank you for the article, I kind of paniced 😄

[BrownTruck]

Hello!

I am an automated bot and I have noticed that this pull request is not currently able to be merged. If you are able to either merge the master branch into this pull request or rebase this pull request against master then it will be eligible for code review and hopefully merging!

[tfolbrecht]

Thank you Mr Bot!
I'll follow up.

[BrownTruck]

Hello!

I am an automated bot and I have noticed that this pull request is not currently able to be merged. If you are able to either merge the master branch into this pull request or rebase this pull request against master then it will be eligible for code review and hopefully merging!

[McSinyx]

What is the status of this @tfolbrecht? May I take this over (basically appending stylistic changes over to satisfy the checks) or do you want to do it?

[tfolbrecht]

I abandoned it @McSinyx. Go for it! I may try again if you don't and I get back into the python ecosystem.

[tfolbrecht]

PR was adopted :) #7828