[Distutils] svn tagging setuptools command

[Phillip J. Eby]

At 12:22 PM 8/30/2005 -0500, Ian Bicking wrote:
>Interesting, I'll have to try that out.  So I'm thinking I might be able 
>to have someone add this to setup.cfg:
>
>   [sqlobject]
>   dbmodule = mypackage.db
>
>And use that to kind of implicitly enable the SQLObject commands.  At 
>least, assuming I can access arbitrary sections of the config from the 
>setup (since sqlobject would imply several commands).  Or alterately in 
>setup.py.  Hrm... maybe it has to be in setup.py, though, since setup.cfg 
>is only used after the command is invoked, so it can't keep the command 
>from being available?  Well, I suppose experimentation is in order.

setup.cfg is loaded and parsed before the command line is, but *after* 
argument processing.  So there isn't really a way to hook into any of that, 
short of loading the config file yourself from a keyword argument 
processor.  It'd be better for you to define a setup() keyword like 
'sqlobject_dbmodule'.  See the CVS version of setuptools.txt under "Adding 
``setup()`` Arguments" for detailed info.

The setup() would also have to list 'setup_requires="SQLObject>=0.7b1"' or 
whatever in order to ensure that the keyword argument is recognized, 
though.  So, the setup might look like:

     setup(
         ...
         setup_requires=["SQLObject>=0.7b1"],
         sqlobject_dbmodule = "mypackage.db",
     )

And there you go.  Your "sqlobject_dbmodule" entry point in the 
"distutils.setup_keywords" group will then define a validation function to 
check that sqlobject_dbmodule has the right type/syntax, and then insert 
any useful command classes into the dist.cmdclass dictionary, making them 
available before command line parsing takes place.