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

On Wed, Apr 3, 2013 at 11:11 PM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
> In any case, the whole exercise is pointless if we don't change the
> visible behavior of array_dims et al.  So I think the idea that this
> would be without visible consequence is silly.  What's up for argument
> is just how much incompatibility is acceptable.

The only reasonable answer for this (a provably used, non-security,
non-standards violating, non-gross functionality breakage case) is
*zero*.  Our historically cavalier attitude towards compatibility
breakage has been an immense disservice to our users and encourages
very bad upgrade habits and is, IMNSHO, embarrassing.

Changing the way array_dims works for a minor functionality
enhancement is gratuitous and should be done, if at all, via a loudly
advertised deprecation/replacement cycle with a guarding GUC (yes, I
hate them too, but not nearly as much as the expense of qualifying
vast code bases against random compatibility breakages every release).

merlin