On 06/10/2016 20:26, Glyph Lefkowitz wrote:
On Oct 6, 2016, at 2:56 AM, Andrew Jaffe wrote:
On 17/09/2016 18:59, Glyph Lefkowitz wrote:
On Sep 17, 2016, at 9:27 AM, Ned Deily wrote:
On 2016-09-13 19:33, Glyph Lefkowitz wrote:
On Sep 13, 2016, at 3:35 PM, Andrew Jaffe wrote:
$ ls -lt /Library/Python/2.7/site-packages/
total 0
-rwxr-xr-x 1 root wheel 157 31 Jul 02:36 Extras.pth*
-rw-r--r-- 1 root wheel 119 31 Jul 02:36 README
$ more /Library/Python/2.7/site-packages/Extras.pth
/System/Library/Frameworks/Python.framework/Versions/2.7/Extras/lib/python
/System/Library/Frameworks/Python.framework/Versions/2.7/Extras/lib/python/PyObjC
Hah! Thanks for sharing. Very satisfying to actually make a *correct*
prediction about setuptools' behavior :)
This seems to be Apple's doing. AFAICT, 10.12 is shipping with this
Extras.pth file in /Library/Python/2.7; it's something new. And,
unfortunately, due to https://bugs.python.org/issue4865, the
site-packages directory for the system Python 2.7 is included in
sys.path along with the non-system framework Python site-packages.
So, a little more data:
If you rename or remove /Library/Python/2.7/site-packages/Extras.pth
then pip2 works.
What do you mean by "works"? Your original error is pip refusing to
upgrade pyObjC because to upgrade pyObjC it has to delete the old
version, and pyObjC is part of the operating system, and it can't delete
the installed version. This is correct; the error reporting could be
nicer, but pip is not broken. Don't mess with files in /System.
The suggestion to use virtualenv isn't really optional. If you really,
really want things to be importable by a bare 'python', not inside a
venv, `pip install --user` is another option you might have.
*However*, lots of other stuff breaks -- anything that uses Apple's
python and relies on access to pyobjc and the frameworks (e.g.,
TextMate's latex package).
Yep, that's expected behavior. This is exactly why Apple is making it
increasingly difficult to screw up /System. Apps can, should, and do
rely upon the libraries installed on the system.
What I don't understand is: what changed from Yosemite? This file did
not exist before Sierra, but there were no problems with (Apple)
python accessing these packages.
Do you mean from El Capitan?
Yes, sorry.
This file previously existed in a different location, and (while the
particulars stubbornly refuse to stick to memory for me, for some
reason) this new location is the one generally preferred by the python
packaging maintainers.
(Or is there something unique in my setup that is causing this? I kind
of doubt it, but it's possible...)
Does anyone have any insight?
If you really, really, really want to do this in such a way that /System
stuff is only present for /System's python and not for python.org
<http://python.org>'s, you can take advantage of the 'import' hack
<https://docs.python.org/2/library/site.html>, and
rewrite /Library/Python/2.7/site-packages/Extras.pth to _conditionally_
add those entries to sys.path, checking sys.executable or some other
fingerprint.
But: don't. Given that system python and python.org <http://python.org>
python share /Library and ~/Library, they're not /really/ distinct
environments, and things installed into one will show up in the other,
so excluding the /System directories on one but not the other will just
cause other, more confusing issues.
In conclusion: just use virtualenv. This is not a problem that should
be fixed.
I agree that this would solve all of the problems, at the cost of some
minor startup pain.
But one nice thing about the python.org builds is that, for the last few
releases, they just worked out of the box, where by "worked" I mean that
(as far as I can tell) the system Python saw its own packages, and the
python.org build saw its own packages, and (python.org) pip didn't seem
to care about the system files. And I suppose I still don't understand
exactly why that changed with Sierra, and whether the change is actually
beneficial in any way whatever! (And whether it could only be fixed by
Apple, or whether a change in the python.org build could do something
about it.)
Sorry to keep harping on about it, but I find it hard to believe this is
not a fairly widespread problem! (Well, I found at least one other
complaint:
https://jasonkratz.com/2016/09/25/python-2-7-on-the-mac-site-package-weirdness/)
Andrew
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