PHP goto Isn't Evil: One Less Nesting Level for Retry Logic

Originally published at recca0120.github.io

The first instinct for retry logic is usually while (true). It works, but the try/catch ends up nested inside the loop, adding an extra indent level and burying the intent slightly.
PHP has goto, and most people skip right past it. But for retry logic specifically, it's one level flatter and the intent is clearer.

The while Version

The common approach:

while (true) {              // first level: the loop
    try {                   // second level: try
        $client = new Client();
        $response = $client->request($method, $uri, array_filter([
            'form_params' => $form_params,
            'multipart'   => $multipart,
        ]));

        return json_decode($response->getBody(), associative: true);

    } catch (ConnectException $e) {
        $times--;
        if (! $times) {
            throw $e;       // only throw when retries are exhausted
        }
        usleep(3000);
        // continue to next while iteration
    }
}

It works fine. But a few things are slightly awkward:

1. while (true) exists purely to "jump back" — it carries no business meaning
2. The entire try/catch is pushed one level right
3. The success path exits via return from inside a loop — it's a side exit, not a natural one

The goto Version

beginning:                  // label — the jump target
try {                       // top level, one less indent
    $client = new Client();
    $response = $client->request($method, $uri, array_filter([
        'form_params' => $form_params,
        'multipart'   => $multipart,
    ]));

    return json_decode($response->getBody(), associative: true);

} catch (ConnectException $e) {
    $times--;
    if (! $times) {
        throw $e;           // retries exhausted — throw
    }
    usleep(microseconds: 3000);
    goto beginning;         // explicitly says "retry" — jump back to label
}

The flow is direct:

• Success → return
• Failure with retries remaining → goto beginning
• Failure with no retries left → throw

The jump only happens when explicitly retrying. There's no implicit "loop continues" logic to reason about.

The Structural Difference

while version:
└── while(true)        ← first level
    └── try { ... }    ← second level
        └── catch

goto version:
└── try { ... }        ← first level (top)
    └── catch
        └── goto beginning

That saved level becomes very noticeable when the try block is long.

PHP goto Constraints

PHP's goto has a few rules:

// ✓ Can jump to a label in the same function
function doRequest() {
    retry:
    try { ... }
    catch (...) { goto retry; }
}

// ✗ Cannot jump into a loop or switch body
for (...) {
    inside:   // cannot goto here from outside the loop
}

// ✗ Cannot jump across functions
function a() { goto label; }
function b() { label: ... }  // not allowed

As long as the target label is in the same function and not inside a loop or switch body, it's valid.

Why goto Has a Bad Reputation

Historical reasons. In the C era, goto was heavily abused to produce spaghetti code with jumps flying everywhere. Dijkstra's 1968 letter "Go To Statement Considered Harmful" cemented goto's association with bad code, and the reputation stuck.

But that critique was aimed at arbitrary jumping, not every use of goto. Jumping backward for retry logic — with a clear, local target and obvious intent — is nothing like the kind of goto that caused problems.

In practice, the Linux kernel still uses goto for cleanup paths in C. You can find occasional goto in Symfony and other major PHP codebases too.

When This Pattern Fits

The goto retry pattern works well when:

• There's a fixed retry count
• Only specific exceptions trigger a retry (here: ConnectException)
• There's a delay between retries (usleep)
• The logic is simple and the jump target is obvious

If the retry logic becomes more complex — exponential backoff, multiple exception types, logging — wrap it in a helper function instead of stretching goto further.

Summary

goto isn't untouchable — it just needs the right context. For retry logic with a clear backward jump, no cross-function leaps, and an obvious target, goto expresses the intent more directly than while (true) and saves a level of nesting.

When you see goto, don't flinch. Look at where it jumps and why, then decide if it needs changing.

References

• PHP Manual: goto — goto syntax rules and constraints
• Dijkstra 1968: Go To Statement Considered Harmful — The seminal paper critiquing arbitrary goto usage
• PHP Manual: Exceptions — Complete guide to try/catch and exception handling