Re: [PATCH] Exorcise "zero-dimensional" arrays (Was: Re: Should array_length() Return NULL)

Robert Haas <robertmhaas@gmail.com> writes:
> Well, you could easily change array_ndims() to error out if ARR_NDIM()
> is negative or more than MAXDIM and return NULL only if it's exactly
> 0.  That wouldn't break backward compatibility because it would throw
> an error only if fed a value that shouldn't ever exist in the first
> place, short of a corrupted database.  I imagine the other functions
> are amenable to similar treatment.

I haven't looked at the patch in detail, but I thought one of the key
changes was that '{}' would now be interpreted as a zero-length 1-D
array rather than a zero-D array.  If we do that it seems a bit moot
to argue about whether we should exactly preserve backwards-compatible
behavior in array_ndims(), because the input it's looking at won't be
the same anymore anyway.

In any case, the entire point of this proposal is that the current
behavior around zero-D arrays is *broken* and we don't want to be
backwards-compatible with it anymore.  So if you wish to argue against
that opinion, do so; but it seems a bit beside the point to simply
complain that backwards compatibility is being lost.
        regards, tom lane