python-pip : ImportError: cannot import name main

Question

I am using Debian 9.5 Stretch release. I am having import error while using pip. When I try using pip it says:

However I can use python:

I have two versions of python installed: 2.7 and 3.5

Output of which pip : /usr/bin/pip

When I tried reinstalling it using apt-get pip worked completely fine for the first time but the next time it shows the same error

Contents of /usr/bin/

Don't know whats the problem.

Solution 1

This most likely happened because you were using two different package managers (dpkg or its frontend apt-get, and pip itself) on the same prefix (/usr). I assume that either

• a recent apt-get upgrade updating some dependencies, but some other files that were installed by pip didn't get updated because dpkg and apt-get simply didn't know about them OR
• you removed a package with apt-get remove, and as apt-get wasn't aware of anything using this package (as the other package was installed by pip and thus not in the dpkg database), it didn't warn you about breaking other packages.

Without knowing which packages were installed with which package manager, I cannot give you any really specific advice how to repair your system, only general advice:

Don't use multiple different package managers. Only ever use one package manager for a given (sub-)tree of your filesystem, or you will get inconsistencies and/or conflicts. Debian's package manager for the /usr tree is called dpkg, and without calling it noone should ever touch /usr.

It certainly doesn't help that most python-related people you'll encounter try to push pip, even going as far as telling you to sudo pip install; don't. There are distro packages containing python stuff for a reason. Also see this related question on AskUbuntu and this answer on StackOverflow.

---

You can try to repair the mess by installing a fresh pip with

apt-get purge python-pip python3-pip
apt-get install python-pip python3-pip

however there may be files left behind that might interfere, which dpkg doesn't know about as they were installed by pip. The sure-fire way would be checking all files under /usr/lib/python* whether they belong to a debian package, and if not, delete them without exception.

Again, only use dpkg and its frontend tools like apt-get, aptitude, synaptic, ... to modify /usr. If you need to install anything system-wide that's not available as .deb package, either create a package and install it with dpkg, or install it under /usr/local.

Solution 2

Set python2.7 as default:

sudo update-alternatives --config python

select python2.7.

Remove pip:

sudo python -m pip uninstall pip
sudo apt purge --autoremove python-pip

Reinstall it:

sudo apt install python-pip

Check the pip --version:

pip 9.0.1 from /usr/lib/python2.7/dist-packages (python 2.7)

Do not upgrade pip to the latest version.

Comments

[Nasir Riley]

Add the output of which pip to your question. Also, did you install 3.5 via apt-get or was it compiled?

[Siddharth Mishra]

i installed it using apt-get

[Siddharth Mishra]

output of which pip : /usr/bin/pip

[Nasir Riley]

In /usr/bin, are is there more than one python and pip such as python and python3 and pip and pip3?

[Nasir Riley]

Try pip install --upgrade pip and pip3 install --upgrade pip.

[Siddharth Mishra]

same error while using pip install --upgrade pip or pip3 install --upgrade pip

[Siddharth Mishra]

Let us continue this discussion in chat.

[schaiba]

Please don't use screenshots of text.

[Siddharth Mishra]

getting errors purging python-pip. Cannot copy the whole log, it's too long

[Wüstengecko]

What's the first actual error message that it displays (with a few lines of pre-context)? Also, try doing apt-get purge python-pip and apt-get purge python3-pip separately.

[Siddharth Mishra]

can't use any of those commands. each of them shows some type of error

[Siddharth Mishra]

dpkg shows some error about unable to configure pip :Do you want to continue? [Y/n] y (Reading database ... 334637 files and directories currently installed.) Removing python-pip (9.0.1-2) ... File "/usr/bin/pyclean", line 63 except (IOError, OSError), e: ^ SyntaxError: invalid syntax dpkg: error processing package python-pip (--remove): subprocess installed pre-removal script returned error exit status 1

[Siddharth Mishra]

removing also shows error : dpkg: error while cleaning up: subprocess installed post-installation script returned error exit status 1 Errors were encountered while processing: python-pip E: Sub-process /usr/bin/dpkg returned an error code (1)

[Siddharth Mishra]

SyntaxError: invalid syntax dpkg: error processing package python-pip (--remove): subprocess installed pre-removal script returned error exit status 1 Traceback (most recent call last): File "/usr/bin/pycompile", line 35, in <module> from debpython.version import SUPPORTED, debsorted, vrepr, \ File "/usr/share/python/debpython/version.py", line 24, in <module> from ConfigParser import SafeConfigParser

[Siddharth Mishra]

ImportError: No module named 'ConfigParser' dpkg: error while cleaning up: subprocess installed post-installation script returned error exit status 1 Errors were encountered while processing: python-pip E: Sub-process /usr/bin/dpkg returned an error code (1)

[Siddharth Mishra]

this was for python-pip

[Siddharth Mishra]

Traceback (most recent call last): File "/usr/bin/pycompile", line 35, in <module> from debpython.version import SUPPORTED, debsorted, vrepr, \ File "/usr/share/python/debpython/version.py", line 24, in <module> from ConfigParser import SafeConfigParser ImportError: No module named 'ConfigParser' dpkg: error processing package python-pip (--configure): subprocess installed post-installation script returned error exit status 1 Errors were encountered while processing: python-pip E: Sub-process /usr/bin/dpkg returned an error code (1)

[Siddharth Mishra]

for python3-pip

[GAD3R]

@SiddharthMishra You get the above error because you have set Python3.5 as default , see my update.

[Siddharth Mishra]

Each command worked except pip --version, it shows the same import error as mentioned in my question

[Alex Jansen]

@GAD3R there's a typo here. It should be "sudo apt purge --autoremove python-pip"

[GAD3R]

@AlexJohnson Thank you.