The instructions in this README are incomplete and not up-to-date. In particular, they do not explain how to create a modern flat installer package from the now obsolete bundle-format installer package produced by build-installer.py.

The build-installer.py script creates Python distributions, including certain third-party libraries as necessary. It builds a complete framework-based Python out-of-tree, installs it in a funny place with $DESTROOT, massages that installation to remove .pyc files and such, creates an Installer package from the installation plus other files in resources and scripts and placed that on a .dmg disk image.

This installers built by this script are legacy bundle installers that have been supported from the early days of OS X. In particular, they are supported on OS X 10.3.9, the earliest supported release for builds from this script.

Beginning with Python 2.7.9, PSF practice is to build two installer variants using the newer flat package format, supported on 10.5+, and signed with the builder's Apple developer key, allowing downloaded packages to satisfy Apple's default Gatekeeper policy (e.g. starting with 10.8, Apple store downloads and Apple developer ID signed apps and installer packages). The process for transforming the output build artifacts into signed flat packages is not yet integrated into build-installer.py.

1. 32-bit-only, i386 and PPC universal, capable on running on all machines supported by Mac OS X 10.5 through (at least) 10.10:

   /usr/bin/python  build-installer.py \
       --sdk-path=/Developer/SDKs/MacOSX10.5.sdk \
       --universal-archs=32-bit \
       --dep-target=10.5
   

   • builds the following third-party libraries

     • libcrypto and libssl from OpenSSL 1.0.1
     • NCurses 5.9
     • SQLite 3.28.0
     • Oracle Sleepycat DB 4.8 (Python 2.x only)

   • uses system-supplied versions of third-party libraries

     • readline module links with Apple BSD editline (libedit)

   • requires ActiveState Tcl/Tk 8.4 (currently 8.4.20) to be installed for building

   • recommended build environment:

     • Mac OS X 10.5.8 Intel or PPC
     • Xcode 3.1.4
     • MacOSX10.5 SDK
     • MACOSX_DEPLOYMENT_TARGET=10.5
     • Apple gcc-4.2
     • bootstrap non-framework Python 2.7 for documentation build with Sphinx (as of 2.7.9)

   • alternate build environments:

     • Mac OS X 10.6.8 with Xcode 3.2.6

       • need to change /System/Library/Frameworks/{Tcl,Tk}.framework/Version/Current to 8.4

     • Note Xcode 4.* does not support building for PPC so cannot be used for this build

2. 64-bit / 32-bit, x86_64 and i386 universal, for OS X 10.6 (and later):

   /usr/bin/python build-installer.py \
       --sdk-path=/Developer/SDKs/MacOSX10.6.sdk \
       --universal-archs=intel \
       --dep-target=10.6
   

   • builds the following third-party libraries

     • NCurses 5.9 (http://bugs.python.org/issue15037)
     • SQLite 3.7.13
     • Oracle Sleepycat DB 4.8 (Python 2.x only)

   • uses system-supplied versions of third-party libraries

     • libcrypto and libssl from Apple OpenSSL 0.9.8
     • readline module links with Apple BSD editline (libedit)

   • requires ActiveState Tcl/Tk 8.5.15 (or later) to be installed for building

   • recommended build environment:

     • Mac OS X 10.6.8 (or later)
     • Xcode 3.2.6
     • MacOSX10.6 SDK
     • MACOSX_DEPLOYMENT_TARGET=10.6
     • Apple gcc-4.2
     • bootstrap non-framework Python 2.7 for documentation build with Sphinx (as of 2.7.9)

   • alternate build environments:

     • none. Xcode 4.x currently supplies two C compilers. llvm-gcc-4.2.1 has been found to miscompile Python 3.3.x and produce a non-functional Python executable. As it appears to be considered a migration aid by Apple and is not likely to be fixed, its use should be avoided. The other compiler, clang, has been undergoing rapid development. While it appears to have become production-ready in the most recent Xcode 5 releases, the versions available on the deprecated Xcode 4.x for 10.6 were early releases and did not receive the level of exposure in production environments that the Xcode 3 gcc-4.2 compiler has had.

• No Fink (in /sw) or MacPorts (in /opt/local) or other local libraries or utilities (in /usr/local) as they could interfere with the build.

• The documentation for the release is built using Sphinx because it is included in the installer. For 2.7.x up to and including 2.7.8, the Doc/Makefile used svn to download repos of Sphinx and its dependencies. Beginning with 2.7.9, the Doc/Makefile assumes there is an externally-provided sphinx-build and requires at least Python 2.6 to run. Because of this, it is no longer possible to build a 2.7.9 or later installer on OS X 10.5 using the Apple-supplied Python 2.5.

• It is safest to start each variant build with an empty source directory populated with a fresh copy of the untarred source.

• It is recommended that you remove any existing installed version of the Python being built:

  sudo rm -rf /Library/Frameworks/Python.framework/Versions/n.n
  

Here are the steps you need to follow to build a Python installer:

• Run build-installer.py. Optionally you can pass a number of arguments to specify locations of various files. Please see the top of build-installer.py for its usage.

  Running this script takes some time, it will not only build Python itself but also some 3rd-party libraries that are needed for extensions.

• When done the script will tell you where the DMG image is (by default somewhere in /tmp/_py).

It is also possible to build a 4-way universal installer that runs on OS X 10.5 Leopard or later:

/usr/bin/python /build-installer.py \
    --dep-target=10.5
    --universal-archs=all
    --sdk-path=/Developer/SDKs/MacOSX10.5.sdk

This requires that the deployment target is 10.5, and hence also that you are building on at least OS X 10.5. 4-way includes i386, x86_64, ppc, and ppc64 (G5). ppc64 executable variants can only be run on G5 machines running 10.5. Note that, while OS X 10.6 is only supported on Intel-based machines, it is possible to run ppc (32-bit) executables unmodified thanks to the Rosetta ppc emulation in OS X 10.5 and 10.6. The 4-way installer variant must be built with Xcode 3. It is not regularly built or tested.

Other --universal-archs options are 64-bit (x86_64, ppc64), and 3-way (ppc, i386, x86_64). None of these options are regularly exercised; use at your own risk.

Ideally, the resulting binaries should be installed and the test suite run on all supported OS X releases and architectures. As a practical matter, that is generally not possible. At a minimum, variant 1 should be run on a PPC G4 system with OS X 10.5 and at least one Intel system running OS X 10.8, 10.7, 10.6, or 10.5. Variant 2 should be run on 10.8, 10.7, and 10.6 systems in both 32-bit and 64-bit modes.:

/usr/local/bin/pythonn.n -m test -w -u all,-largefile
/usr/local/bin/pythonn.n-32 -m test -w -u all

Certain tests will be skipped and some cause the interpreter to fail which will likely generate Python quit unexpectedly alert messages to be generated at several points during a test run. These are normal during testing and can be ignored.

It is also recommend to launch IDLE and verify that it is at least functional. Double-click on the IDLE app icon in /Applications/Pythonn.n. It should also be tested from the command line:

/usr/local/bin/idlen.n