Doc #75801 [NEW]: Mistake in documentation example for null coalesce operator

From: pieter at frenssen dot be Operating system: PHP version: Irrelevant Package: Documentation problem Bug Type: Documentation Problem Bug description:Mistake in documentation example for null coalesce operator Description: ------------ --- From manual page: http://www.php.net/language.operators.comparison --- The example given for the null coalesce operator is not correct. This is the current example: <?php // Example usage for: Null Coalesce Operator $action = $_POST['action'] ?? 'default'; // The above is identical to this if/else statement if (isset($_POST['action'])) { $action = $_POST['action']; } else { $action = 'default'; } ?> It says that it is equivalent to using isset() in an if/else statement, but this is not true. If $_POST['action'] would be set with the value NULL then the first expression would assign the value default, but the second would assign the value NULL. In fact it is equivalent to using !empty(), so the example should be corrected to the following: <?php // Example usage for: Null Coalesce Operator $action = $_POST['action'] ?? 'default'; // The above is identical to this if/else statement if (!empty($_POST['action'])) { $action = $_POST['action']; } else { $action = 'default'; } ?> or possibly to the following, if we want to keep using isset() which is also mentioned elsewhere in the documentation: <?php // Example usage for: Null Coalesce Operator $action = $_POST['action'] ?? 'default'; // The above is identical to this if/else statement if (isset($_POST['action']) && !is_null($_POST['action'])) { $action = $_POST['action']; } else { $action = 'default'; } ?> -- Edit bug report at https://bugs.php.net/bug.php?id=75801&edit=1 -- Try a snapshot (PHP 5.4): https://bugs.php.net/fix.php?id=75801&r=trysnapshot54 Try a snapshot (PHP 5.5): https://bugs.php.net/fix.php?id=75801&r=trysnapshot55 Try a snapshot (trunk): https://bugs.php.net/fix.php?id=75801&r=trysnapshottrunk Fixed in SVN: https://bugs.php.net/fix.php?id=75801&r=fixed Fixed in release: https://bugs.php.net/fix.php?id=75801&r=alreadyfixed Need backtrace: https://bugs.php.net/fix.php?id=75801&r=needtrace Need Reproduce Script: https://bugs.php.net/fix.php?id=75801&r=needscript Try newer version: https://bugs.php.net/fix.php?id=75801&r=oldversion Not developer issue: https://bugs.php.net/fix.php?id=75801&r=support Expected behavior: https://bugs.php.net/fix.php?id=75801&r=notwrong Not enough info: https://bugs.php.net/fix.php?id=75801&r=notenoughinfo Submitted twice: https://bugs.php.net/fix.php?id=75801&r=submittedtwice register_globals: https://bugs.php.net/fix.php?id=75801&r=globals PHP 4 support discontinued: https://bugs.php.net/fix.php?id=75801&r=php4 Daylight Savings: https://bugs.php.net/fix.php?id=75801&r=dst IIS Stability: https://bugs.php.net/fix.php?id=75801&r=isapi Install GNU Sed: https://bugs.php.net/fix.php?id=75801&r=gnused Floating point limitations: https://bugs.php.net/fix.php?id=75801&r=float No Zend Extensions: https://bugs.php.net/fix.php?id=75801&r=nozend MySQL Configuration Error: https://bugs.php.net/fix.php?id=75801&r=mysqlcfg