Aina za error/exception katika PHP ni zipi?

Question

Accepted Answer

PHP ina mifumo miwili sambamba ya matatizo: **errors** za jadi (warnings, notices, fatal errors) na **exceptions** (zenye msingi wa object, zinazoweza kunaswa kwa try/catch). PHP ya kisasa huunganisha mengi ya haya chini ya hierarchy ya `Throwable`, na mazoea mazuri hupendelea exceptions.

## Error levels za jadi

```text
E_NOTICE   → minor issues (e.g. using an undefined variable) — script continues
E_WARNING  → non-fatal problems (e.g. include of a missing file) — continues
E_ERROR / Fatal → serious errors (e.g. calling an undefined function) — script HALTS
E_DEPRECATED → use of deprecated features
```

Hizi ni errors za kawaida za PHP zenye msingi wa level. Notices na warnings huruhusu script kuendelea (lakini huashiria matatizo); fatal errors huisimamisha.

## Hierarchy ya Throwable (ya kisasa, yenye msingi wa object)

```text
Throwable (interface)
  ├── Error      → internal PHP/engine errors (TypeError, DivisionByZeroError, ...)
  │                 — typically PROGRAMMING bugs
  └── Exception  → application-level exceptions (the ones you throw and catch)
        ├── RuntimeException, LogicException
        ├── InvalidArgumentException, etc.
        └── your custom exceptions
```

PHP ya kisasa huwakilisha matatizo mazito kama **objects** zinazotekeleza `Throwable`, zikigawanywa katika `Error` (kiwango cha engine, mara nyingi bugs kama `TypeError`) na `Exception` (application errors unazozua na kushughulikia).

## Kunasa kwa try/catch

```php
try {
    $result = riskyOperation();
} catch (InvalidArgumentException $e) {     // catch a SPECIFIC type
    echo "Bad argument: " . $e->getMessage();
} catch (Throwable $e) {                     // catch anything (Error OR Exception)
    log($e);
} finally {
    cleanup();                                // always runs
}
```

Tangu PHP 7, hata `Error`s (kama `TypeError`) zinaweza kunaswa kama `Throwable` — kwa hivyo unaweza kunasa errors na exceptions zote.

## Kuzua exceptions

```php
function divide(int $a, int $b): float {
    if ($b === 0) {
        throw new InvalidArgumentException("Cannot divide by zero");   // raise
    }
    return $a / $b;
}
```

## Kusanidi error handling

```php
error_reporting(E_ALL);         // report ALL errors (development)
ini_set('display_errors', '0'); // production: DON'T show errors to users (log them instead)
set_error_handler(...);          // convert errors to exceptions, custom handling
```

## Kwa nini ni muhimu

Kuelewa mfumo wa error na exception wa PHP ni muhimu kwa kuandika applications imara na ku-debug kwa ufanisi.

Kujua **error levels** za jadi (notice/warning/fatal) hukusaidia kutafsiri ujumbe wa PHP na kutambua uzito wa matatizo, wakati kuelewa **hierarchy ya `Throwable`** ya kisasa (mgawanyo kati ya `Error`s za kiwango cha engine — mara nyingi programming bugs — na `Exception`s za application unazozua na kunasa) ni ufunguo wa error handling ya PHP ya kisasa.

Ujuzi wa kivitendo — kutumia `try/catch/finally` kushughulikia exceptions, kunasa types mahususi, kuzua exceptions zenye maana, na kwamba hata `Error`s zinaweza kunaswa kama `Throwable` (tangu PHP 7) — ni ujuzi wa kila siku kwa kujenga code ya kuaminika.

Muhimu, kujua mazoea ya production ya **kuandika logs za errors badala ya kuzionyesha kwa users** (kwa kuwa errors zinazoonyeshwa hufichua taarifa nyeti — jambo la usalama) ni muhimu kwa deployment salama.

PHP ya kisasa hupendelea njia yenye msingi wa exception na object-oriented, kwa hivyo kuelewa aina za error/exception, jinsi ya kuzishughulikia ipasavyo, na error configuration salama ni ujuzi wa msingi kwa kuandika PHP applications imara, zinazoweza ku-debug, na salama.