Engine Exceptions — Error Hierarchy (PHP 7.0)

TL;DR

Explanation

PHP 7.0 introduced the Error class (distinct from Exception) implementing Throwable. Engine errors that previously caused uncatchable fatals now throw Error subclasses: ParseError (eval syntax errors), TypeError (type declaration violations), ArithmeticError / DivisionByZeroError (math errors), AssertionError (assert() failures), Error (generic engine errors). catch (\Throwable $t) catches everything. catch (\Error $e) catches engine errors only. This unified PHP's error handling — no more register_shutdown_function() to detect fatal errors that were actually TypeError.

Common Misconception

Why It Matters

Common Mistakes

• Catching Exception when TypeError/Error should also be caught.
• Not knowing that each Error subclass can be caught specifically.
• Missing the Throwable interface — it's what unifies Error and Exception.

Code Examples

try {
    $result = intdiv(10, 0);
} catch (Exception $e) {
    // Never reached! DivisionByZeroError extends Error, not Exception
}

try {
    $result = intdiv(10, 0);
} catch (DivisionByZeroError $e) {
    $result = 0; // Specific
} catch (\Error $e) {
    throw new AppException('Engine error', previous: $e);
} catch (\Throwable $t) {
    // Catch-all for both Error and Exception
}

References

• ↗ https://www.php.net/manual/en/language.errors.php7.php

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