Re: The impact of a module's license on the requiring Lua

[Enrico Tassi <gares@...>]

On Tue, Apr 17, 2012 at 08:21:52AM +0200, steve donovan wrote:
> On Mon, Apr 16, 2012 at 10:26 PM, Jay Carlson <nop@nop.com> wrote:
> > Lua on Linux uses readline. This is not an abstract issue.
> 
> I've been worried ever since that linked document claimed that
> readline _was_ a problem for non-GPL software, despite Miles'
> assurances.

Well, on my Debian system '/usr/bin/lua5.1' is linked with readline.  
If Miles is wrong, and I don't think so, what happens? Nothing. The lua
interpreter inherits GPL and my lua scripts stays exaclty as they are,
under the license I gave to them. 
Well, one may complain that the copyright file included with the Lua
package is wrong, but still there is nothing illegal going on there. A
GPL version of the lua interpreter can still be distributed, it is still
free software, and its sources are freely available.

On my very same Debian system, all applications using stock lua link
against /usr/lib/.../liblua5.1.so.0.0.0 that is not itself linked with
readline. So They can be licensed as their authors wanted them to be.

Moreover, even if I find it ridicolous, one could still claim GPL infects 
lua.c, the interpreter main loop, but not the rest, that is clearly not
a derived work since it does not even use the readline APIs, and can be
built as a library not linked against readline.
Even in an embedded software that statically links the lua code, the
interpreter (lua.c) is very likely to be left out, and with it any
reference to readline.

Last, if you don't like readline, and you really think it's a problem to 
link against it, just link with libedit. "Problem" solved.

Please don't make the awesome lua list look like debian-legal!

Regards.
-- 
Enrico Tassi