AssertionError: Egg-link {path} does not match installed location of {package}

[mrmachine]

• Pip version: 9.0.0, 9.0.1
• Python version: 2.7.13
• Operating system: Ubuntu Xenial

Description:

I have installed an editable package into /opt/django-dynamic-fixture (PIP_SRC=/opt) when building a Docker image. When I run a container with this image, we set PYTHONUSERBASE=$PROJECT_DIR/var/src so we can do pip install --user ... and:

1. Make use of existing packages already installed in the Docker image
2. Ignore (instead of uninstalling) conflicting packages already installed (first rule listed here: https://pip.pypa.io/en/stable/user_guide/#user-installs)

The reason 2. above is important is the existing packages are in an ephemeral and possibly read only file system when the Docker container runs.

This works fine with pip<9.0.0 but no longer works with 9.0.0 and 9.0.1.

Here's the error:

bash-4.3# pip install -e 'git+https://github.com/ixc/django-dynamic-fixture.git@caeb3427399edd3b0d589516993c7da55e0de560#egg=django-dynamic-fixture'
Obtaining django-dynamic-fixture from git+https://github.com/ixc/django-dynamic-fixture.git@caeb3427399edd3b0d589516993c7da55e0de560#egg=django-dynamic-fixture
  Skipping because already up-to-date.
Requirement already satisfied: six in /usr/lib/python2.7/dist-packages (from django-dynamic-fixture)
Installing collected packages: django-dynamic-fixture
  Found existing installation: django-dynamic-fixture 1.9.0
Exception:
Traceback (most recent call last):
  File "/opt/django-icekit/project_template/var/docker-pythonuserbase/lib/python2.7/site-packages/pip/basecommand.py", line 215, in main
    status = self.run(options, args)
  File "/opt/django-icekit/project_template/var/docker-pythonuserbase/lib/python2.7/site-packages/pip/commands/install.py", line 342, in run
    prefix=options.prefix_path,
  File "/opt/django-icekit/project_template/var/docker-pythonuserbase/lib/python2.7/site-packages/pip/req/req_set.py", line 778, in install
    requirement.uninstall(auto_confirm=True)
  File "/opt/django-icekit/project_template/var/docker-pythonuserbase/lib/python2.7/site-packages/pip/req/req_install.py", line 701, in uninstall
    '(at %s)' % (link_pointer, self.name, dist.location)
AssertionError: Egg-link /opt/django-icekit/project_template/var/src/django-dynamic-fixture does not match installed location of django-dynamic-fixture (at /opt/django-dynamic-fixture)
bash-4.3# 

This seems to be a regression, as the docs linked above still indicate existing packages should be ignored (not uninstalled).

[MartinThoma]

https://stackoverflow.com/a/48972085/562769

[MartinThoma]

I think this issue should be closed.

[DevMMI]

Use pip install -e <package_dir> -I to ignore other installed packages and overwrite them

[uranusjr]

Since -I (i.e. --ignore-installed) does not attempt to uninstall previously-installed dependencies, it is better to use --no-deps to only fix the broken editable.

The command I recommend is

pip install --no-deps -I -e <package>

I agree with pip’s current approach to be safe and not aggressively remove the broken link. This is ultimately an environment problem that is best handled by the user. The error message has room for improvement, but that’s better filed as a separate enhancement issue IMO.