pip >=19.2 cannot install packages via custom URLs with "one element" auth

[slafs]

Environment

• pip version: >= 19.2
• Python version: 2.7.10 and 3.7.2
• OS: macOS Mojave

Description

When trying to install a package from a custom URL that requires authentication (e.g. from GitHub private repo releases), pip doesn't properly handle parsing of "one element" auth info e.g. GitHub access tokens (i.e. without : like the usual user:password auth info).

Expected behavior

I want to be able to install my package from a private GitHub repo with an Auth Token like this:

pip install https://myaccesstoken@github.com/myorganization/myprivaterepo/archive/myrelease.zip#egg=mypackage

this works fine with pip==19.1.1

How to Reproduce

1. Create a private repo on GitHub with one release (can be empty).
2. Create an access token at https://github.com/settings/tokens/new for private repos
3. Try to install that release package (.zip) using the created token with pip>=19.2 like in the section above.

The output should mention a successful download of the package and a "setup.py not found" error message (if the release was empty).

Workaround

As a workaround one can put : before or after the access token so the URL looks like:

https://:myaccesstoken@github.com/...

Output
Instead of installing the package, pip fails with "ERROR: HTTP error 404 while getting https://...".

I've created an empty private repo, with an empty release to test that. The output for pip install -vvv ... can be found here:

• for pip 19.2,
• for pip 19.1.1 (with expected setup.py not found error).

The issue/difference can be observed around Starting new HTTPS connection (1): github.com:443.

Cause
I've run a git bisect session for this issue and it pointed to this commit c63ee61

This issue was also discussed at #6775 (see #6775 (comment) and #6775 (comment)).

[haizaar]

Another bummer with this bug is that pipenv automatically uses the latest pip when instantiating new venv, hence people keep bumping into this.

[pradyunsg]

@slafs Does this occur with #6795?

[slafs]

Nope. Looks like #6795 fixes the problem 👍

[pradyunsg]

Released pip 19.2.2 containing a fix for this issue. :)