[Python-Dev] Dodgy code in distutils/sysconfig.py

[M.-A. Lemburg]

Michael Hudson wrote:
> I'm curious about this bit of code from Lib/distutils/sysconfig.py:
> 
> ,-----------------------------------------------------------------------
> | # python_build: (Boolean) if true, we're either building Python or
> | # building an extension with an un-installed Python, so we use
> | # different (hard-wired) directories.
> |
> | argv0_path = os.path.dirname(os.path.abspath(sys.executable))
> | landmark = os.path.join(argv0_path, "Modules", "Setup")
> | if not os.path.isfile(landmark):
> |     python_build = 0
> | elif os.path.isfile(os.path.join(argv0_path, "Lib", "os.py")):
> |     python_build = 1
> | else:
> |     python_build = os.path.isfile(os.path.join(os.path.dirname(argv0_path),
> |                                                "Lib", "os.py"))
> | del argv0_path, landmark
> `-----------------------------------------------------------------------
> 
> Well, curious is a bit weak.  It's broken, and breaks (eg) the snake
> farm's builds (because that is set up to build python in a directory
> far away and over the hills from the source directory).
> 
> Why isn't it just
> 
> ,-----------------------------------------------------------------------
> | # python_build: (Boolean) if true, we're either building Python or
> | # building an extension with an un-installed Python, so we use
> | # different (hard-wired) directories.
> |
> | argv0_path = os.path.dirname(os.path.abspath(sys.executable))
> | landmark = os.path.join(argv0_path, "Modules", "Setup")
> | 
> | python_build = os.path.isfile(landmark):
> | 
> | del argv0_path, landmark
> `-----------------------------------------------------------------------
> 
> ?  What cases does that get wrong?  I'd have changed it already, but I
> have this feeling I must be missing something.

Is Modules/Setup a landmark on all Python build platforms,
e.g. on Macs, Windows and other non-Unix platforms as well ?

-- 
Marc-Andre Lemburg
CEO eGenix.com Software GmbH
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