Re: [HACKERS] Readline use in trouble?

Milan Zamazal <pdm@debian.cz> writes:
>>>>>> "TL" == Tom Lane <tgl@sss.pgh.pa.us> writes:
TL> The GPL does restrict the conditions under which GPL'd code can
TL> be distributed; in particular it can't be distributed as part of
TL> a program that is not all GPL'd (more or less --- I have not
TL> read the terms lately).  So, because we use BSD license rather
TL> than GNU, we cannot *include in our distribution* any library
TL> that is under GPL.

> I think that from the point of GPL there is basically no problem with
> PostgreSQL license, since it contains no restriction incompatible with
> GPL.

Actually it's the other way around: BSD-type license doesn't care about
GPL'd stuff in the same distribution ... but GPL license does.  The GPL
insists that all its terms, including its restrictions, apply exactly
to the whole of any program containing any GPL'd code.  So we'd be
violating the GPL if we had parts of Postgres under GPL and parts under
BSD, because BSD is *less* restrictive than GPL (it puts fewer
requirements on a recipient of the code than GPL does).  And we can't
just arbitrarily change the Berkeley-derived code from BSD to GPL.

In practice this is probably all just nit-picking; the Postgres group
itself isn't doing anything with Postgres that doesn't fall within the
terms of the GPL.  But from a legalistic point of view the two licenses
are not compatible.
        regards, tom lane