Re: Undefined variables and the array append operator

On Wed, Mar 30, 2022, at 9:11 AM, Claude Pache wrote: >> Le 29 mars 2022 à 21:44, Rowan Tommins <rowan.collins@gmail.com> a écrit : >> >> Hi all, >> >> If $foo is not defined, statements such as $foo += 1 and $foo .= 'blah' raise >> "undefined variable" Warnings in PHP 8, and will throw Errors in PHP 9. However, the very >> similar looking $foo[] = 1 succeeds silently. >> >> This seems odd to me, as "append to string" and "append to array" seem >> like very similar operations, with most of the same use cases and possible bugs. >> >> > > > Hi, > > There are various subcases to consider: > > (1) $x[] = 42; and $x['y'] = 42; where $x is undefined > > (2) $x[] = 42; and $x['y'] = 42; where $x is null > > (3) $x['y'][] = 42; and $x['y']['w'] = 42; where $x is an > array, and > $x['y'] is undefined. > > Of course, I agree that (1) should be an error. > > The case (3) is similar to (1), but I think it is more controversial to > change. I bet that they are various places in my code that take > advantage of that feature, although personally I don’t mind to write > $x['y'] ??= [ ]; when needed. We should probably also consider if there are other places where we're comfortable with ??= working correctly. I'm not sure off hand if it should be acceptable in 1 or 2, but it's a question we should think through and document decisions on. --Larry Garfield