Python 2.6.4 and Twisted 9 on OS X 10.6 Snow Leopard

27 December 2009

I just recently purchased a MacBook Pro, which comes with Snow Leopard installed, and I noticed that it comes with python 2.6.1 installed. I wanted to upgrade to the latest python release of 2.6.4, so I tried installing the official python Mac OS distribution from After installation, I wanted to install Twisted and I kept getting this error below:

creating build/temp.macosx-10.3-fat-2.6
creating build/temp.macosx-10.3-fat-2.6/twisted
creating build/temp.macosx-10.3-fat-2.6/twisted/runner
gcc-4.0 -arch ppc -arch i386 -fno-strict-aliasing -fno-common -dynamic -DNDEBUG -g -O3 -I/Library/Frameworks/Python.framework/Versions/2.6/include/python2.6 -c twisted/runner/portmap.c -o build/temp.macosx-10.3-fat-2.6/twisted/runner/portmap.o
In file included from /usr/include/architecture/i386/math.h:626,
 from /usr/include/math.h:28,
 from /Library/Frameworks/Python.framework/Versions/2.6/include/python2.6/pyport.h:235,
 from /Library/Frameworks/Python.framework/Versions/2.6/include/python2.6/Python.h:58,
 from twisted/runner/portmap.c:10:
/usr/include/AvailabilityMacros.h:108:14: warning: #warning Building for Intel with Mac OS X Deployment Target < 10.4 is invalid.
Compiling with an SDK that doesn't seem to exist: /Developer/SDKs/MacOSX10.4u.sdk
Please check your Xcode installation
gcc-4.0 -arch ppc -arch i386 -isysroot /Developer/SDKs/MacOSX10.4u.sdk -g -bundle -undefined dynamic_lookup build/temp.macosx-10.3-fat-2.6/twisted/runner/portmap.o -o build/lib.macosx-10.3-fat-2.6/twisted/runner/
ld: library not found for -lbundle1.o
ld: library not found for -lbundle1.o
collect2: ld returned 1 exit status
collect2: ld returned 1 exit status
lipo: can't open input file: /var/folders/T6/T6diKRiFGJSwsabKP4864E+++TI/-Tmp-//ccIK1c3K.out (No such file or directory)
error: command 'gcc-4.0' failed with exit status 1

Something's not right -- setuptools is detecting that I'm using macosx-10.3, but I'm using Mac OS X 10.6.  Why is it that setuptools also wants to use /Developer/SDKs/MacOS10.4u.sdk to build python extensions? I'm currently using the SDK for Mac OS X 10.6, and I don't want to install another SDK.

Well, I did a little bit of research and I learned that PSF's 2.6.4 python package for a Mac is built with an option called --enable-universalsdk which, according to the readme, defaults to /Developer/SDKs/MacOSX.10.4u.sdk. This is why building third-party extensions tries to reference the 10.4 SDK.

I was able to build python successfully using the following:

./configure --enable-framework --enable-universalsdk=/Developer/SDKs/MacOSX10.6.sdk/ --with-universal-archs=intel
make && make test
sudo make install

You'll notice that the following 3 tests failed when attempting to run the unit tests:

The test that should really put you on alert is asyncore. After doing some research, it turns out the asyncore module is using some variant of select.poll(), which isn't supported by the FreeBSD kernel. FreeBSD uses something called kqueue, which is what the test doesn't take into account. To fix this, I pulled the module from the trunk and overwrote /Lib/ The tests passed then.

You don't need to fix the other two, as they only pertain to fixing the actual tests themselves instead of having to actually change a module. If you're interested though, fixing "test_platform" follows the same pattern as asyncore. Brett Cannon actually filed a bug for this test and submitted a patch, but you will still need to replace the entire module to get it working. Apparently, this patch is for python v2.7, v3.1, and v3.2. To fix it, download the patched module and replace it with the one in /Lib/test/ Make sure you also delete /Lib/test/test_platform.pyc.

The last test, test_macostools, is actually quite interesting. Apparently, Apple does not supply 64-bit versions of the Carbon frameworks used by these modules. This is why this test is failing. Looks like there might not be a way to fix this test until Apple upgrades the Carbon frameworks to 64-bit usage.

After fixing these bugs, make sure you run the following command:

sudo make install

Needless to say, after I installed python with the options above, and after I fixed all these modules, the Twisted 9.0 installation was successful.

I hope this helps some of you in case you run into this problem!

This entry was tagged as programming python software

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