为什么 pip 要安装我的软件包的旧版本？

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Got the same issue to update pika 0.9.5 to 0.9.8. The only working way was to install from tarball: pip install https://pypi.python.org/packages/source/p/pika/pika-0.9.8.tar.gz.

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I found here that there is a known bug in pip that it won't check the version if there's a build directory with unpacked sources. I have checked this on my troubling package and after deleting its sources from build directory pip installed the required version.

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最佳答案

This is an excellent question. It took me forever to figure out. This is the solution that works for me:

Apparently, if pip can find a local version of the package, pip will prefer the local versions to remote ones. I even disconnected my computer from the internet and tried it again -- when pip still installed the package successfully, and didn't even complain, the source was obviously local.

The really confusing part, in my case, was that pip found the newer versions on pypi, reported them, and then went ahead and re-installed the older version anyway ... arggh. Also, it didn't tell me what it was doing, and why.

So how did I solve this problem?

You can get pip to give verbose output using the -v flag ... but one isn't enough. I RTFM-ed the help, which said you can do -v multiple times, up to 3x, for more verbose output. So I did:

pip install -vvv <my_package>

Then I looked through the output. One line caught my eye:

Source in /tmp/pip-build-root/ has version 0.0.11, which satisfies requirement <my_package>

I deleted that directory, after which pip installed the newest version from pypi.

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Thanks to Marcus Smith, who does amazing work as a maintener of pip, this was fixed in version 1.4 of pip which was released on 2013-07-23.

Relevant information from the changelog for this version

Fixed a number of issues (#413, #709, #634, #602, and #939) related to cleaning up and not reusing build directories. (Pull #865, #948)

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If you are using a pip version that comes with some distribution packages (ex. Ubuntu python-pip), you may need to install a newer pip version:

Update pip to latest version:

sudo pip install -U pip

In case of "virtualenv", skip "sudo":

pip install -U pip

Following command may be required, if your shell report something like -bash: /usr/bin/pip: No such file or directory after pip update:

hash -d pip

Now install your package as usual:

pip install -U foo

or

pip install foo==package.version.here

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Try forcing download the package again with:

pip install --no-cache-dir --upgrade <package>

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I found that if you use microversions, pip doesn't seem to recognize them. For example, we couldn't get version 1.9.9.1 to upgrade.

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In my case the python version used (3.4) didn't satisfy Django 2.1 dependencies requirements (python >= 3.5).

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For my case I had to delete the .pip folder in my home directory and then I was able to get later versions of multiple libraries. Note that this was on linux.

pip --version
pip 18.1 from /usr/lib/python2.7/site-packages/pip (python 2.7)
virtualenv --version
15.1.0

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In my case I am pip installing a .tar.gz package from Artifactory that I make a lot of updates to. In order to overwrite my cached Python files and always grab/install the latest I was able to run:

pip install --no-cache-dir --force-reinstall <path/to/tar.gz>

You should see this re-download any necessary files and install those, instead of using your local cache.

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In my case, someone had published the latest version of a package with python2, so attempting to pip3 install it grabbed an older version that had been built with python3.

Handy things to check when debugging this:

If pip install claims to not be able to find the version, see whether pip search can see it.
Take a look at the "Download Files" section on the pypi repo -- the filenames might suggest what's wrong (in my case i saw -py2- there clear as day).
As suggested by others, try running pip install --no-cache-dir in case pip isn't bothering to ask the internet because it already has your answer locally.

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I had hidden unversioned files under the Git tab in PyCharm that were being installed with pip install . even though I didn't see the files anywhere else.

Took a long time to find it for me, posting this in hope that it'll help somebody else.

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Just in case that anyone else hassles with upgrading torchtext (or probably any other torch library):

Although https://pypi.org/project/torchtext/ states that you could run pip install torchtext I had to install it similiar to torch by specifying --find-links aka -f:

pip install torchtext===0.8.1 -f https://download.pytorch.org/whl/torch_stable.html

What irritated me was that PyCharm pointed me to the new version, but couldn't find it when attempting to upgrade to it. I guess that PyCharm uses its own mechanism to spot new versions. Then, when invoking pip under the hood, it didn't find the new version without the --find-links option.

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if you need the path for your package do pip -v list. Example see related post when using pip -e Why is an old version of a package of my python library installing by itself with pip -e?

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10 years on and pip still fails to work as expected 😖.

I wasted a couple of hours now banging my head against the wall trying to find out why pip won't install a development version of my package. In my case, there are versions 0.0.4 and 0.0.5.dev1 in a private gitlab.com package registry (hence the --extra-index-url argument below), but I believe that's not relevant to the problem.

Following a lot of the advice on this page, I create a test venv in a far away folder, clear the pip cache, uninstall the package in question, etc. first to rule out the most common problems:

$ pip cache purge && \
pip uninstall --yes my-package && \
pip install --extra-index-url "https://_:${GITLAB_PASSWORD_TOOLS_VAULTTOOLS}@gitlab.com/api/v4/projects/<project-id>/packages/pypi/simple" \
--no-cache-dir  \
--pre           \
--upgrade my-package

output (using empty lines to separate output for commands):

WARNING: No matching packages
Files removed: 0


Found existing installation: my-package 0.0.4
Uninstalling my-package-0.0.4:
Successfully uninstalled my-package-0.0.4


Looking in indexes: https://pypi.org/simple, https://_:****@gitlab.com/api/v4/projects/<project-id>/packages/pypi/simple
Collecting my-package
Downloading https://gitlab.com/api/v4/projects/<project-id>/packages/pypi/files/f07 ... 397/my_package-0.0.5.dev1-py3-none-any.whl (16 kB)
Downloading https://gitlab.com/api/v4/projects/<project-id>/packages/pypi/files/775 ... 70e/my_package-0.0.4-py3-none-any.whl (16 kB)
...
Successfully installed my-package-0.0.4

So pip does see the dev package version, but chooses the earlier one nonetheless.

In an attempt to figure out what's going on, I published a 0.0.5 version: Error persists, pip sees all three versions, but still installs 0.0.4.

In a further, increasingly desperate attempt, I removed any versions prior to 0.0.5* from the gitlab.com package registry.

Only now, pip would bother to actually display some useful information:

$ (same command as above)
... (similar output as above) ...
ERROR: Cannot install my-package==0.0.5 and my-package==0.0.5.dev1 because these package versions have conflicting dependencies.


The conflict is caused by:
my-package 0.0.5 depends on my-other-package<0.2.5 and >=0.2.4
my-package 0.0.5.dev1 depends on my-other-package<0.2.5 and >=0.2.4


To fix this you could try to:
1. loosen the range of package versions you've specified
2. remove package versions to allow pip attempt to solve the dependency conflict


ERROR: ResolutionImpossible: for help visit https://pip.pypa.io/en/latest/topics/dependency-resolution/#dealing-with-dependency-conflicts

OK, so there is something wrong with my package dependencies. Thanks for letting me know.

Seriously - I tried hard for a couple of hours using all kinds of pip ... -vvv and/or fixed versions such as e.g. my-package==0.0.5.dev1 - but I did not manage to get any useful output out of pip - until I wiped the entire history from my package registry 🤬.

Hope this at least helps someone in the same situation.