Pull Request for Issue #16970 .
Fix regression for Issue #15228 .

Summary of Changes

Revert to previous individual preg_match rather than combine them into 1.

Testing Instructions

Check your PHP error log.

or

Create the following PHP script and run it. 1st preg_match( (previous) outputs no error. 2nd preg_match( (current) outputs error.

<?php

$agent = "Mozilla/5.0 (iPad; CPU OS 10_3_2 like Mac OS X) AppleWebKit/603.1.30 (KHTML, like Gecko) CriOS/59.0.3071.102 Mobile/14F89 Safari/602.1";

echo 'v3.6.5 ';
preg_match('|CriOS[/ ]([0-9.]+)|', $agent, $version);
var_dump($version);
list ($majorVersion, $minorVersion) = explode('.', $version[1]);

echo 'v3.7.3 ';
preg_match('/Chrome[\/ ]([0-9.]+)|CrMo[\/ ]([0-9.]+)|CriOS[\/ ]([0-9.]+)/i', $agent, $version);
var_dump($version);
list ($majorVersion, $minorVersion) = explode('.', $version[1]);

?>

results (1st array is v3.6.5 and 2nd array is v3.7.3):

v3.6.5 array(2) {
  [0]=>
  string(19) "CriOS/59.0.3071.102"
  [1]=>
  string(13) "59.0.3071.102"
}
v3.7.3 array(4) {
  [0]=>
  string(19) "CriOS/59.0.3071.102"
  [1]=>
  string(0) ""
  [2]=>
  string(0) ""
  [3]=>
  string(13) "59.0.3071.102"
}
<br />
<b>Notice</b>:  Undefined offset: 1 in <b>C:\xampp\htdocs\agent.php</b> on line <b>14</b><br />

Expected result

No PHP Notice

Actual result

PHP message: PHP Notice: Undefined offset: 1 in /libraries/joomla/environment/browser.php on line 282\n

Documentation Changes Required

None