On 6/18/06, Nick Coghlan <[EMAIL PROTECTED]> wrote: > The implementations of PEP 328 (explicit relative imports) and PEP 338 > (executing modules as scripts) currently have a fight over the __name__ > attribute of a module. > > The -m switch sets __name__ to '__main__', even though it knows the module's > real name. This is so that "if __name__ == '__main__':" blocks get executed > properly in the main module. > > Relative imports, however, use __name__ to figure out the parent package, > which obviously won't work if the -m switch has clobbered it. > > I think this is a solvable problem, but with beta 1 going out in a couple of > days, I don't know if it's too late in the 2.5 cycle to fix it. > > If Anthony's willing to class this as a bug fix, it should be possible to get > it sorted out by beta 2. I think fixing it will actually be easier than trying > to write documentation explaining why it doesn't work right ;) > > The 'bug fix' solution would be: > > 1. Change main.c and PySys_SetPath so that '' is NOT prepended to sys.path > when the -m switch is used > 2. Change runpy.run_module to add a __pkg_name__ attribute if the module > being executed is inside a package > 3. Change import.c to check for __pkg_name__ if (and only if) __name__ == > '__main__' and use __pkg_name__ if it is found.
That's pretty heavy-handed for a pretty esoteric use case. (Except #1, which I think should be done regardless as otherwise we'd get a messed-up sys.path.) I'd like to understand the use case better. Why can't a "script" module inside a package use absolute imports to reference other parts of the package? > If we don't fix it, I'd like to document somewhere that you can't currently > rely on relative imports if you want to be able to execute your module with > the '-m' switch. > > However, the question I have then is. . . where? It's pretty esoteric, so I > don't really want to put it in the tutorial, but I can't think of any other > real documentation we have that covers how to launch the interpreter or the > "if __name__ == '__main__':" trick. With the docs for -m, obviously. -- --Guido van Rossum (home page: http://www.python.org/~guido/) _______________________________________________ Python-Dev mailing list Python-Dev@python.org http://mail.python.org/mailman/listinfo/python-dev Unsubscribe: http://mail.python.org/mailman/options/python-dev/archive%40mail-archive.com
