Ned Deily posted the following on Pythonmac-SIG just now. It's probably of interest to many of us on this list. Note that Lion ships with *three* versions of Python installed.
> Here's my take on things after installing and some quick testing with > 10.7 Lion: > > - If you were satisfied with using the Apple-supplied Pythons in > previous OS X releases, you'll probably be satisfied with the 2.7, 2.6, > or 2.5 system Pythons in 10.7. > > - You should not rely on the Apple-suppled Pythons if you want to use > IDLE. > http://www.python.org/download/mac/tcltk/ > > - If you prefer to use more recent Pythons and have been satisfied with > python.org OS X installers, use the most recent 3.2.1 or 2.7.2 > 64-bit/32-bit (x86-64 / i386) installers for Mac OS X: > http://www.python.org/download/ > As with 10.6, if you are planning to use IDLE or Tkinter with these > installers, you should also install the most recent ActiveTcl 8.5 if you > can (check the license terms): > http://www.activestate.com/activetcl/downloads > > - If you need to install any Python packages that build C extension > modules, you'll need to install Xcode for Lion (currently 4.1 and now > available for free download through the Mac App store). > > - The traditional python.org 32-bit-only 10.3+ (i386/PPC) Pythons can be > installed on 10.7 and do work in general; however, it is not practical > to build C extension modules on 10.7 that will work with them (since > Xcode 4 no longer includes the 10.4u SDK nor gcc-4.0). Unless you have > specialized needs and know what you are doing, you should avoid using > the traditional 32-bit-only installers on 10.7 in favor of either using > the 64-bit/32-bit variants, using versions from a different distributor, > or building your own. As on 10.6, if you need to run in 32-bit mode, > you can use "python3.2-32" or "python2.7-32" with the 64-bit/32-bit > variants. > > > > Random details: > > Apple ships 10.7 with 3 system Pythons: > > /usr/bin/python2.7 > Python 2.7.1 (r271:86832, Jun 16 2011, 16:59:05) > [GCC 4.2.1 (Based on Apple Inc. build 5658) (LLVM build 2335.15.00)] on > darwin > /usr/bin/python2.6 > Python 2.6.6 (r266:84292, Jun 16 2011, 16:59:16) > [GCC 4.2.1 (Based on Apple Inc. build 5658) (LLVM build 2335.15.00)] on > darwin > /usr/bin/python2.5 > Python 2.5.5 (r255:77872, Jun 16 2011, 16:58:16) > [GCC 4.2.1 (Based on Apple Inc. build 5658) (LLVM build 2335.15.00)] on > darwin > > The 2.7 and 2.6 instances are 2-way Intel universal binaries (x86_64 and > i386); the 2.5 one is i386 (32-bit) only. The 2.7 version, at least, > comes pre-installed with various 3rd-party packages, like setupttols, > PyObjC, py2app, numpy, twisted, Zope, etc, similar to what was shipped > for 2.6 in 10.6. (I didn't look at the 2.6 and 2.5 frameworks.) The > downside of shipping these packages is that some, including Python > itself, are not the latest versions. > > Tcl/Tk: As in 10.6, Apple ships two versions of Tcl/Tk: a Cocoa Tk 8.5 > and the venerable Carbon Tk 8.4. The 8.5 version has been updated to > 8.5.9. The Tkinters in all three Apple-supplied Pythons are linked with > 8.5. The good news is that the updated 8.5 is not the disaster that the > 10.6 version was. The bad news is that it is missing at least one fix > to Tk from earlier this year: > Cocoa Tk crashes when typing a composite character into a text field > (http://sourceforge.net/tracker/index.php?func=detail&aid=2907388&group_i > d=12997&atid=112997). The fix for this crash is incorporated into the > most recent ActiveTcl 8.5 releases for OS X. However, the system > Pythons will not attempt to dynamically link to user-installed Tcl/Tk > frameworks in /Library (where the ActiveState frameowrks are installed), > unlike the Pythons installed by python.org installers. So, out of the > box, the IDLE versions that come with the system Pythons are vulnerable > to this. But at least they aren't totally unusable as was the case with > 10.6. And I suppose if there are enough bug reports this fix might get > applied in a future 10.7 update. > > Although it's not practical to build packages with C extension modules > on 10.7 for the traditional 32-bit-only python.org Pythons (as explained > above), it is possible to build such packages with the same Python > installed on a 10.6, 10.5, or even 10.4 system, create a Distutils bdist > or setuptools/Distribute bdist-egg and then install the binary > distribution on the 10.7 system. I would avoid going down that path if > possible, unless it is needed as a temporary transition phase. > > -- > Ned Deily, > n...@acm.org > > _______________________________________________ > Pythonmac-SIG maillist - pythonmac-...@python.org > http://mail.python.org/mailman/listinfo/pythonmac-sig > unsubscribe: http://mail.python.org/mailman/options/Pythonmac-SIG