What are common issues with undefined variables in PHP, especially when upgrading from PHP 5 to PHP 8?

Common issues with undefined variables in PHP, especially when upgrading from PHP 5 to PHP 8, include stricter error handling that may result in notices or warnings being thrown for accessing undefined variables. To solve this issue, ensure all variables are properly initialized before use to avoid errors. 

// Before PHP 8
$variable; // Notice: Undefined variable

// After PHP 8
$variable = ''; // Initialize variable to avoid errors

Keywords

undefined variables PHP 5 PHP 8 backward compatibility error_reporting

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