I would also prefer (2) for exactly the example given in this thread. The Windows version of curses.missing.py could raise a ModuleNotFoundError saying that curses is not available on Windows, but a developer who wants to can install PDCurses to implement the stdlib module.
I don't think the few cases where an stdlib package is both missing and has a name collision with an incompatible module are enough to outweigh the benefits of being able to install a third-party package to implement a missing part of the stdlib Alex On 2016-11-28 11:38 AM, Guido van Rossum wrote: > Overall I think this is a good idea. I have one hit: > > It seems that there are two possible strategies for searching the > .missing.py file: > > 1. (Currently in the PEP) search it at the same time as the .py file > when walking along sys.path. > - Pro: prevents confusion when the user accidentally has their own > matching file later in sys.path. > - Con: prevents the user from installing a matching file > intentionally (e.g. a 3rd party version). > > 2. After exhausting sys.path, search it again just for .missing.py > files (or perhaps remember the location of the .missing.py file during > the first search but don't act immediately on it -- this has the same > effect). > - Pro: allows user to install their own version. > - Con: if the user has a matching file by accident, that file will > be imported, causing more confusion. > > I personally would weigh these so as to prefer (2). The option of > installing your own version when the standard version doesn't exist > seems reasonable; there may be reasons that you can't or don't want to > install the distribution's version. I don't worry much about the > danger of accidental name conflicts (have you ever seen this?). > > > --Guido > > On Mon, Nov 28, 2016 at 8:13 AM, Paul Moore <p.f.mo...@gmail.com > <mailto:p.f.mo...@gmail.com>> wrote: > > On 28 November 2016 at 15:51, Tomas Orsava <tors...@redhat.com > <mailto:tors...@redhat.com>> wrote: > > I believe I may have found the Windows curses implementation, > it's called > > PDCurses [0], and this website [1] appears to be distributing it > under the > > name `curses`. > > My apologies, I should have included a pointer. That is indeed the > distribution I was thinking of. > > > Could some Windows user please check if compiling Python with > the current > > reference implementation [2] of this PEP indeed generates a > > `curses.missing.py <http://curses.missing.py>` file among the > stdlib files? If so, we might consider > > skipping the generation of the .missing.py file for the curses > module on > > Windows. > > I'll see if I can make some time to do the test. But as the change is > to setup.py, and the Windows build uses Visual Studio project files to > do the build, I expect that it won't generate missing.py files on > Windows. In actual fact, that may be the simplest solution, to note > that the build part of this change is restricted to Unix (non-Windows) > platforms specifically. As there's no real concept of a "distribution > version" of Python on Windows, it's probably not something that will > be that important on that platform (and support for .missing.py files > is there, it would just be necessary for distributors to manually > create those files as needed). > > Paul > _______________________________________________ > Python-ideas mailing list > Python-ideas@python.org <mailto:Python-ideas@python.org> > https://mail.python.org/mailman/listinfo/python-ideas > <https://mail.python.org/mailman/listinfo/python-ideas> > Code of Conduct: http://python.org/psf/codeofconduct/ > <http://python.org/psf/codeofconduct/> > > > > > -- > --Guido van Rossum (python.org/~guido <http://python.org/%7Eguido>) > > > _______________________________________________ > Python-ideas mailing list > Python-ideas@python.org > https://mail.python.org/mailman/listinfo/python-ideas > Code of Conduct: http://python.org/psf/codeofconduct/
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