Re: Re: On arrays starting with a negative index

On 01/03/2017 20:46, Pedro Magalhães wrote:

As a clarification, the current implementation of the PR affects arrays in general, not only array_fill. Any array that starts with a negative index would continue from that index instead of 0. Meaning that [-2 => true, true, true] would now return [-2 => true, -1 => true, 0 => true] instead of [-2 => true, 0 => true, 1 => true].

Hi Pedro, Would other behaviour also be affected? For instance: $foo = [ -2 => true ]; $foo[] = true; $foo[] = true; var_dump($foo); If so, this is a much wider BC break; if not, why not? Currently, this is completely consistent: https://3v4l.org/hXAsf Indeed, I would say this is the missing explanation of why array_fill works the way it does. Presumably, this is why there is a note on the manual page:

See also theArrays <http://php.net/manual/en/language.types.array.php> section of manual for a detailed explanation of negative keys.

Although as pointed out by Andrew Nester, this "detailed explanation" doesn't actually seem to exist. This seems to be the closest we get:

As mentioned above, if no key is specified, the maximum of the existing integer indices is taken, and the new key will be that maximum value plus 1 (but at least 0). If no integer indices exist yet, the key will be 0 (zero).

Hidden in that first rambling sentence is the key phrase "but at least 0"; and the second should really say "If no positive integer indices..." [It shouldn't say "exist", either, because as the next paragraph explains, it can actually be affected by keys that no longer exist; which I'd never actually realised before!] This deserves to be a full section rather than a note, and much more clearly articulated. It might even make sense to split that page into sub-pages in some way, but I'm drifting into a different discussion, for a different list. The point right now is that array_fill's behaviour is actually consistent with the rest of the language, and while the value of that behaviour is questionable, changing it now would be a major decision. Regards, -- Rowan Collins [IMSoP]