Re: Bug#189164: libdbd-mysql-perl uses GPL lib, may be used by GPL-incompatible apps
Anthony DeRobertis <email@example.com>:
> 1) Library GPLLib is under the GPL
> 2) Perl module Iface provides an interface to various implementations
> of similar features, and the user selects which implementation to
> 3) Perl modules PM uses GPLLib to implement Iface
> 4) Perl program P is under a GPL-incompatible license
> Is is permissible for P to use PM through Iface?
Yes, of course, because the GPL doesn't restrict use!
> I argue "yes" because I don't see how P could _possibly_ be held to be
> a derived worked of GPLLib, and thus is not subject to the GPLs
P is not a derived work of GPLLib, but P+GPLLib is likely to be a
derived work of GPLLib, in which case it is not allowed to distribute
them together. However, you could certainly distribute P on its own if
you could reasonably claim that P is useful without GPLLib.
> I further argue that if the answer is "no", there is no good reason to
> say changing the language from perl to shell script should matter, and
> thus no GPL-incompatibly licensed program can use GNU grep, ls, etc.
There are other implementations of grep, ls, etc, so it would
certainly be all right to distribute the GPL-incompatible shell script
on its own. Debian would distribute the shell script with GNU grep,
ls, etc, so you'd have to find another argument why the script is a
separate work from grep, ls, etc, which is probably doable if the
script makes relatively minor use of grep, etc to do something
independently interesting, but would be a bit harder if the script
implements a graphical interface to grep.
That's how I see it, anyway.