Installing 3.4b3 on Windows to test issue 20053, I was surprised to find that after installation, "pip install <package>" didn't work.

I had forgotten that due to the flat executable namespace on POSIX systems, we only install pip3 and pip3.4 by default - you have to pass "--default-install" to ensurepip to get it to install the unqualified "pip".

For virtual environments, we handle that in the venv module - it passes "--default-pip" when invoking the ensurepip CLI.

Given that Windows uses "python" for both Python 2 & 3 (in contrast to the POSIX python/python3 and python2/python3 conventions), perhaps we should be passing --default-install to ensurepip in the Windows installers as well?

I had not noticed that, but yes. It would be unreasonable on Windows to install pip3 and pip3.4 but not plain pip. So +1 on this change.

(In fact, on Windows, omitting the versioned names would conform more closely to how Python is installed, but it's not something that's worth losing sleep over).

Martin, the addition of "--default-install" to the ensurepip args is all that should be needed (it won't trigger if pip isn't upgraded, but rc2 will contain 0.15.3 to fix a couple of glitches that remained in rc1)

Martin?  Do you concur?

This was still missing from rc2 - this is a *serious* usability issue on Windows and needs to be fixed before 3.4 final.

POSIX already has the python/python3 convention, so extending that to pip is reasonable. Windows has no such convention, and the "pip3" naming is just confusing there. We need to install "pip" as well.

And if that means we need an rc3, then we should *absolutely* do one. It's that important.

While it occurs to me that changing ensurepip's default behaviour on
Windows is likely a better long term (3.5+) solution, I think passing the
option in the installer is still the better near term (3.4 rc3/final)
solution.

Sorry, I had not noticed this issue so far. The patch looks fine, please apply.

New changeset ec42ab5e0cb3 by Nick Coghlan in branch 'default':
Close #20568: install unversioned pip command on Windows
http://hg.python.org/cpython/rev/ec42ab5e0cb3

Unfortunately, the patch was incorrect. The option is called --default-pip, not --default-install (the patch had it right, but the committed change is wrong). As a consequence, the installer currently completely fails, as the unrecognized option causes a rollback of the entire Python installation.

New changeset 16f91d87ff39 by Martin v. Löwis in branch 'default':
Issue #20568: Fix typo in pip option.
http://hg.python.org/cpython/rev/16f91d87ff39

cherry-picking in issue20830

Thanks Martin - my apologies for retyping the change (and introducing the
error) rather than just applying the patch (I had assumed, perhaps
incorrectly, that wouldn't apply cleanly due to the UAC changes, but
obviously didn't properly check the retyped version against the original
patch)

New changeset 5d190cca2f47 by Nick Coghlan in branch '3.4':
Close #20568: install unversioned pip command on Windows
http://hg.python.org/cpython/rev/5d190cca2f47

New changeset 3f8ca67bde4d by Martin v. Löwis in branch '3.4':
Issue #20568: Fix typo in pip option.
http://hg.python.org/cpython/rev/3f8ca67bde4d