I've just uploaded a new version of my package to PyPi (1.2.1.0-r4): I can download the egg file and install it with easy_install, and the version checks out correctly. But when I try to install using pip, it installs version 1.1.0.0 instead. Even if I explicitly specify the version to pip with pip install -Iv tome==1.2.1.0-r4, I get this message: Requested tome==1.2.1.0-r4, but installing version 1.1.0.0, but I don't understand why.
I double checked with parse_version and confirmed that the version string on 1.2.1 is greater than that on 1.1.0 as shown:
>>> from pkg_resources import parse_version as pv
>>> pv('1.1.0.0') < pv('1.2.1.0-r4')
True
>>>
So any idea why it's choosing to install 1.1.0 instead?
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 -v -v -v <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.
Try forcing download the package again with:
pip install --no-cache-dir --upgrade <package>
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)
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.
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
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.
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.
In my case the python version used (3.4) didn't satisfy Django 2.1 dependencies requirements (python >= 3.5).
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
来源：https://stackoverflow.com/questions/14617136/why-is-pip-installing-an-old-version-of-my-package