[postgis-devel] Hey, you broke... (SRID=0)

[Sandro Santilli]

On Thu, Sep 29, 2011 at 11:00:00AM +0200, Sandro Santilli wrote:
> On Wed, Sep 28, 2011 at 05:03:14PM -0700, Paul Ramsey wrote:
> > Well, it regresses...
> > While I like having SRID=0, I have the worry that this particular
> > change-for-changes sake will rebound on us poorly. It's done, but I'm
> > waffling. Knowing that, at a minimum, our own Java components embed
> > this backward compatibility issue is sobering. How many others also
> > do? Many, I'm sure.
> 
> I suggest setting up a wiki page listing all the breakage cases
> we may think of. I'm pretty dumb in that I can't see any serious
> compatibility problem.
> 
> Didn't check why java hard-coded the -1, for example.
> 
> BTW, does allowing -1 mean we need signed SRID in typmod and thus
> half the MAXALLOWEDSRID ?

Here's one case: scripting procedures handling SRID=-1 in a special way
to mean "dunno", like for example to assume the SRID is to be considered
as matching the one of the other operand.

We could "fix" this (in the long run) by having ST_SRID() return NULL
rather than -1 (or 0) when the SRID is semantically unknown.

--strk; 

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