Re: Re: Array dereference on scalar / null values

On 18 Mar 2014 06:17, "Tjerk Meesters" <tjerk.meesters@gmail.com> wrote: > > Hi internals, > > I've done some bug report gathering on essentially the following behaviour: > > $a = 123; var_dump($a[1]); // "NULL" > $b = true; var_dump($b[1]); // "NULL" > $f = fopen('file', 'r'); var_dump($f[1]); // "NULL" > $n = null; var_dump($n[1]); // "NULL" > > Bug reports: > > https://bugs.php.net/bug.php?id=37676 > https://bugs.php.net/bug.php?id=40692 > https://bugs.php.net/bug.php?id=62769 > https://bugs.php.net/bug.php?id=64194 > https://bugs.php.net/bug.php?id=65484 > > From the comments it seems that there's some disagreement within the group, > for example: > > Nikita: "I would tentatively classify this as a bug." > Tony: "Reclassified as feature request.." > Xinchen: "there was a similar bug report of this behavior, and I seems made > a fix for it." > Ilia: "this is not a bug." x 2 > Joe: "it is the only reasonable thing _to expect_" > > From my understanding, developers are expecting to see notices when this > happens, something like "Cannot use integer/boolean/resource/null as array > in %s on line %d"; I think they're okay with the fact that the end result > will still be "NULL", though. > > The list() operator has since complicated matters; if we would > indeed > introduce notices as requested, the following code would cause issues: > > $array = [1, 2, 3]; > while (list($key, $value) = each($array)) { > echo "$key = $value\n"; > } > > The return value of each() - as it has reached the end of an > array - is > false, so the above code would show two notices. Unfortunately, > we must > assume that all code in the manual are actually used and so it would surely > break stuff when introduced. > > We could mitigate this issue by having each() return > null instead and > introduce notices for all other scalars, but this code is not unlikely: > > while (($data = each($array)) !== false) { > echo "${data[0]} = ${data[1]}\n"; > } > > So my question is, how should we handle this? Close all bug reports and add > something to the documentation? Allow array dereference only on booleans > *and* null? > The alternative is treating list() as the special case and suppressing the error there. I'd prefer this over allowing bool/null to be dereferenced silently in the general case, since it would keep the special handling where it belongs - I.e. where the conflict is. > > Best, > Jack