Description:
------------
From the documentation, parse_ini_file() and parse_ini_string() should support value interpolation:

var_dump(parse_ini_string('
foo = bar
baz = ${foo}
'));

should produce:

array(2) {
  ["foo"]=>
  string(3) "bar"
  ["baz"]=>
  string(3) "bar"
}

but it produces this instead:

array(2) {
  ["foo"]=>
  string(3) "bar"
  ["baz"]=>
  string(0) ""
}

See it live: https://3v4l.org/K15ft

On the other hand, env var value interpolation seems to work:

var_dump(parse_ini_string('
path = ${PATH}
'));

result:

array(1) {
  ["path"]=>
  string(13) "/usr/bin:/bin"
}

See it live: https://3v4l.org/cE4dL



Test script:
---------------
var_dump(parse_ini_string('
foo = bar
baz = ${foo}
'));


Expected result:
----------------
array(2) {
  ["foo"]=>
  string(3) "bar"
  ["baz"]=>
  string(3) "bar"
}


Actual result:
--------------
array(2) {
  ["foo"]=>
  string(3) "bar"
  ["baz"]=>
  string(0) ""
}