haphpiness

Multi-Catch — One Block, Many Exception Types

Two exception types, one recovery strategy, and no shared parent class. Before PHP 7.1 that meant copying the handler, or catching something far too broad and hoping.

// Before: the same three lines, twice.
try {
    $result = $client->send($request);
} catch (NetworkException $e) {
    $this->logger->warning('retrying', ['error' => $e->getMessage()]);
    return $this->retry($request);
} catch (TimeoutException $e) {
    $this->logger->warning('retrying', ['error' => $e->getMessage()]);
    return $this->retry($request);
}

// After: one block, both types, and $e is typed as the union.
try {
    $result = $client->send($request);
} catch (NetworkException | TimeoutException $e) {
    $this->logger->warning('retrying', ['error' => $e->getMessage()]);
    return $this->retry($request);
}

The alternative people actually reached for was catch (Exception $e), which quietly swallows the LogicException from your own broken code alongside the network blip you meant to handle. Multi-catch removed the incentive to be sloppy: naming both types is now shorter than being vague.

PHP 8.0 finished the thought by making the variable optional, for when the type is the information.

try {
    $config = $this->loadConfig();
} catch (FileNotFound | ParseError) {
    // We know what happened. We don't need the object.
    $config = Config::defaults();
}