Building a Python Mac OS X distribution
=======================================

The ``build-install.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.

For Python 3.4.0, PSF practice is to build two installer variants
for each release.

1. 32-bit-only, i386 and PPC universal, capable on running on all machines
 supported by Mac OS X 10.5 through (at least) 10.9::

 /path/to/bootstrap/python2.7 build-installer.py \
 --sdk-path=/Developer/SDKs/MacOSX10.5.sdk \
 --universal-archs=32-bit \
 --dep-target=10.5

 - builds the following third-party libraries

 * NCurses 5.9 (http://bugs.python.org/issue15037)
 * SQLite 3.8.11
 * XZ 5.0.5

 - 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 3.4.1)

 - 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)::

 /path/to/bootstrap/python2.7 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 3.8.11
 * XZ 5.0.5

 - uses system-supplied versions of third-party libraries

 * readline module links with Apple BSD editline (libedit)

 - requires ActiveState Tcl/Tk 8.5.15.1 (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 3.4.1)

 - 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.


* For Python 2.7.x and 3.2.x, the 32-bit-only installer was configured to
 support Mac OS X 10.3.9 through (at least) 10.6. Because it is
 believed that there are few systems still running OS X 10.3 or 10.4
 and because it has become increasingly difficult to test and
 support the differences in these earlier systems, as of Python 3.3.0 the PSF
 32-bit installer no longer supports them. For reference in building such
 an installer yourself, the details are::

 /usr/bin/python build-installer.py \
 --sdk-path=/Developer/SDKs/MacOSX10.4u.sdk \
 --universal-archs=32-bit \
 --dep-target=10.3

 - builds the following third-party libraries

 * Bzip2
 * NCurses
 * GNU Readline (GPL)
 * SQLite 3
 * XZ
 * Zlib 1.2.3
 * Oracle Sleepycat DB 4.8 (Python 2.x only)

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

 - recommended build environment:

 * Mac OS X 10.5.8 PPC or Intel
 * Xcode 3.1.4 (or later)
 * ``MacOSX10.4u`` SDK (later SDKs do not support PPC G3 processors)
 * ``MACOSX_DEPLOYMENT_TARGET=10.3``
 * Apple ``gcc-4.0``
 * system Python 2.5 for documentation build with Sphinx

 - 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``



General Prerequisites
---------------------

* 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 and 3.x.x up to and
 including 3.4.0, the ``Doc/Makefile`` uses ``svn`` to download repos of
 ``Sphinx`` and its dependencies. Beginning with 3.4.1, 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 3.4.1 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


The Recipe
----------

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 3th-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``).

Building other universal installers
...................................

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.


Testing
-------

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
10.9, 10.8, 10.7, 10.6, or 10.5. Variant 2 should be run on 10.9, 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/Python n.n``.
It should also be tested from the command line::

 /usr/local/bin/idlen.n