NetBeans "Variable $out seems to be uninitialized"

Question

While in general hints are a good thing, there's a situation which I find pretty annoying and was wondering if there's an easy way around it.

Consider a function which has an output-only variable:

function dumb_foo($param1, $param2, &$out = null) {
  $out = $param1.'||'.$param2;
  return $param1*$param2;
}

Now making a call such as:

dumb_foo(5, 6, $my_out);

Results in a hint even though it's filled by the function. So yes, it's possible to initialize the variable first

$my_out = null;
dumb_foo(5, 6, $my_out);

but it's redundant.

Is there any other way to avoid the hint in this situation without removing it completely or adding an unneeded initialization?

Answer 1

To the best of my knowledge, I think the best way is to first look at how pass by reference actually works.

case 1: Referenced variable $in already initialized but parameter$out NOT initialized

function increment(&$out) {
  $out++;
}

$in = 4 ; //NOTE: already initialized
increment($in);
echo $in; //add up to 5

case 2: Referenced variable $in NOT initialized but parameter$out initialized

    function increment(&$out = 4) {
      $out++;
    }

    //No initialization of $in
    increment($in);
    echo $in; // add up to 1
    //NOTE:No effect on referenced variable

case 3: Referenced variable $in NOT initialized and parameter$out NOT initialized

    function increment(&$out) {
      $out++;
    }

    //No initialization of $in
    increment($in);
    echo $in; //add up to 1

In my own opinion, case 3, will be a valid solution for the example you describe. Therefore removing the initialization of both $out and $my_out should do the work just fine. Something like this:

function dumb_foo($param1, $param2, &$out) {
  $out = $param1.'||'.$param2;
  return $param1*$param2;
}
dumb_foo(5, 6, $my_out);

Hope this helps!