python package 版本与本地版本 label

Question

I'm using local version label as it is suggested in PEP440 , and I packaged 2 versions: turicreate-6.2 and turicreate-6.2+minimal .

I first install turicreate 6.2+minimal ,

$ pip install target/turicreate-6.2+minimal-cp36-cp36m-macosx_10_12_intel.macosx_10_12_x86_64.macosx_10_13_intel.macosx_10_13_x86_64.macosx_10_14_intel.macosx_10_14_x86_64.whl

Then I try to install 6.2 and I hope pip can uninstall 6.2+minimal , but it says

pip install turicreate==6.2
Requirement already satisfied: turicreate==6.2 in ./env36/lib/python3.6/site-packages (6.2+minimal)

I'm quite confused. it treats version 6.2 and local version (redistribute version) 6.2+minimal as the same. But why?

If I reverse the process, by installing 6.2 first and then 6.2+minimal , pip will uninstall 6.2 first. It seems to be that pip treats these 2 versions differently.

$ pip install target/turicreate-6.2+minimal-cp36-cp36m-macosx_10_12_intel.macosx_10_12_x86_64.macosx_10_13_intel.macosx_10_13_x86_64.macosx_10_14_intel.macosx_10_14_x86_64.whl
Processing ./target/turicreate-6.2+minimal-cp36-cp36m-macosx_10_12_intel.macosx_10_12_x86_64.macosx_10_13_intel.macosx_10_13_x86_64.macosx_10_14_intel.macosx_10_14_x86_64.whl
...
Requirement already satisfied: chardet<4,>=3.0.2 in ./env36/lib/python3.6/site-packages (from requests>=2.9.1->turicreate==6.2+minimal) (3.0.4)
Installing collected packages: turicreate
  Attempting uninstall: turicreate
    Found existing installation: turicreate 6.2
    Uninstalling turicreate-6.2:
      Successfully uninstalled turicreate-6.2
Successfully installed turicreate-6.2+minimal

Answer 1

PEP 0440 states the following:

Except where specifically noted below, local version identifiers MUST NOT be permitted in version specifiers, and local version labels MUST be ignored entirely when checking if candidate versions match a given version specifier.

Which in your case means that you want to install 6.2 , pip finds existing 6.2+minimal , the local part +minimal is ignored because that's the way it should be, so pip is happy it doesn't need to do stuff. You're not happy because that's not what you want, though...

Going the other way around, my guess is that you're specifying a particular (local) version, which the 6.2 does NOT match, so pip does it.