pip uses incorrect cached package version, instead of the user-specified version
PythonPipPython Problem Overview
I need to install psycopg2 v2.4.1 specifically. I accidentally did:
pip install psycopg2
Instead of:
pip install psycopg2==2.4.1
That installs 2.4.4 instead of the earlier version.
Now even after I pip uninstall psycopg2 and attempt to reinstall with the correct version, it appears that pip is re-using the cache it downloaded the first time.
How can I force pip to clear out its download cache and use the specific version I'm including in the command?
Python Solutions
Solution 1 - Python
If using pip 6.0 or newer, try adding the --no-cache-dir option (source).
If using pip older than pip 6.0, upgrade it with pip install -U pip.
Solution 2 - Python
Clear the cache directory where appropriate for your system
Linux and Unix
~/.cache/pip # and it respects the XDG_CACHE_HOME directory.
OS X
~/Library/Caches/pip
Windows
%LocalAppData%\pip\Cache
UPDATE
With pip 20.1 or later, you can find the full path for your operating system easily by typing this in the command line:
pip cache dir
Example output on my Ubuntu installation:
➜ pip3 cache dir
/home/tawanda/.cache/pip
Solution 3 - Python
With pip 20.1 or later, you can do:
pip cache remove matplotlib: removes all wheel files related to matplotlib from pip's cache.pip cache purge: to clear all wheel files from pip's cache.pip cache dir: to get the location of the cache.
If you want to not use the pip cache for some reason (which is a bad idea, according the official docs), your options are:
pip install --no-cache-dir <package>: install a package without using the cache, for just this run.pip config set global.no-cache-dir false: configure pip to not use the cache "globally" (in all commands).
Some history around this question (puts on pip maintainer hat):
The specific issue of "installing the wrong version due to caching" issue mentioned in the question was fixed in pip 1.4, back in 2013!)
> Fix a number of issues related to cleaning up and not reusing build directories. (#413, #709, #634, #602, #939, #865, #948)
Since pip 6.0 (back in 2014!), pip install, pip download and pip wheel commands can be told to avoid using the cache with the --no-cache-dir option. (eg: pip install --no-cache-dir <package>)
Back then, yes, passing --no-cache-dir was the only option to avoid this bug. So... it's a bit unfortunate that this is the top search result on "pip cache remove". :)
Since pip 10.0 (back in 2018!), a pip config command was added, which can be used to configure pip to always ignore the cache. This was always possible by manually editting the relevant files, but this surfaced that ability to the command line. Details on pip's configuration mechanisms is available here.
Since pip 20.1, pip has a pip cache command to manage the contents of pip's cache.
Solution 4 - Python
From documentation at https://pip.pypa.io/en/latest/reference/pip_install.html#caching:
> Starting with v6.0, pip provides an on-by-default cache which
> functions similarly to that of a web browser. While the cache is on by
> default and is designed do the right thing by default you can disable
> the cache and always access PyPI by utilizing the --no-cache-dir
> option.
Solution 5 - Python
pip can install a package ignoring the cache, like this
pip --no-cache-dir install scipy
Solution 6 - Python
Since pip 20.1b1, which was released on 21 April 2020 and "added pip cache command for inspecting/managing pip’s wheel cache", it is possible to issue this command:
pip cache purge
The reference guide is here:
https://pip.pypa.io/en/stable/reference/pip_cache/
The corresponding pull request is here.
Solution 7 - Python
On Ubuntu, I had to delete /tmp/pip-build-root.
Solution 8 - Python
If you like to set the --no-cache-dir option by default, you can put this into pip.conf:
[global]
no-cache-dir = false
Note 1: It's confusing, but to enable the no-cache-dir option you actually have to set it to false. Pretty silly if you ask me... but that's how it is. There is a github issue to fix this.
Note 2: The location of pip.conf depends on your OS. See the documentation for more info.
Solution 9 - Python
I just had a similar problem and found that the only way to get pip to upgrade the package was to delete the $PWD/build (%CD%\build on Windows) directory that might have been left over from a previously unfinished install or a previous version of pip (it now deletes the build directories after a successful install).
Solution 10 - Python
On archlinux pip cache is located at ~/.cache/pip, I could solve my issue by removing the http folder inside it.
Solution 11 - Python
On my mac I had to remove the cache directory ~/Library/Caches/pip/
Solution 12 - Python
Simply
rm -d -r "$(pip cache dir)"
Solution 13 - Python
On Windows 7, I had to delete %HOMEPATH%/pip.
Solution 14 - Python
If using virtualenv, look for the build directory under your environments root.
Solution 15 - Python
I had to delete %TEMP%\pip-build On Windows 7
Solution 16 - Python
(pyvenv.d) jdoe$ pip --version # pip version for this answer (or newer).
pip 21.1.1
(pyvenv.d) jdoe$ pip cache --help # Review all options available to you.
(pyvenv.d) jdoe$ pip cache dir # Cache-directory for pip(1).
/home/jdoe/.cache/pip
(pyvenv.d) jdoe$ pip cache purge # Purge cache-directory (by example).
Files removed: 621 # If cache-directory is already empty, the
# output will be: "ERROR: No matching packages".
Solution 17 - Python
On Mac OS (Mavericks), I had to delete /tmp/pip-build/
Solution 18 - Python
A better way to do it is to delete the cache and rebuild it. In this way, if you install it again for other virtualenv, it will use the cache instead of building every time when you install it.
For example, when you install it, it will say it uses cached wheel,
Processing <some_prefix>/Library/Caches/pip/wheels/d0/c4/e4/e49fd07bca8dda00dd6b4bbc606aa05a25aacb00d45747a47a/horovod-0.19.3-cp37-cp37m-macosx_10_9_x86_64.wh
Just delete that one and restart your install.
Solution 19 - Python
>(...) it appears that pip is re-using the cache (...)
I'm pretty sure that's not what's happening. Pip used to (wrongly) reuse build directory not cache. This was fixed in version 1.4 of pip which was released on 2013-07-23.