symfony/var-dumper · error · LogicException

" " object holds non-iterable type " ".

Error message

"%s" object holds non-iterable type "%s".

What it means

Data::getIterator() implements Traversable over the underlying value, but only when that value is an array. Calling it on a Data wrapping a scalar, string, or other non-array type throws a LogicException because iteration is meaningless for those values.

Solutions

1. Check the value type before iterating: call $data->getValue() and is_array() it, or use $data->count()/type()
2. Only iterate Data objects that wrap arrays; use ->getValue() for scalars
3. If the value may be scalar, wrap iteration in an is_array guard

Example fix

// before
foreach ($data as $k => $v) { ... }
// after
$value = $data->getValue();
if (is_array($value)) {
    foreach ($value as $k => $v) { ... }
}

$value = $data->getValue();
if (!is_array($value)) {
    throw new \LogicException('Expected array value, got '.get_debug_type($value));
}

function isIterableData(\Symfony\Component\VarDumper\Cloner\Data $data): bool {
    return is_array($data->getValue());
}

try {
    foreach ($data as $k => $v) { /* ... */ }
} catch (\LogicException $e) {
    if (str_contains($e->getMessage(), 'non-iterable')) {
        // handle scalar: use $data->getValue() directly
    } else {
        throw $e;
    }
}

When it happens

Trigger: foreach over a Data object whose wrapped value is not an array, e.g. `foreach ($cloned->data as ...)` where the cloned value is a string, int, null, or object.

Common situations: Treating a dumped/cloned variable as always iterable; var-dumper clone results where the top-level value is scalar; code assuming dump output shape without checking the value type first.

Understand the failure class

Background: "is not a compatible type" / "cannot merge" errors: when a value's type doesn't match what the library requires — this error's family across 65 libraries.

Related errors

• objects are immutable.
• The nonce closure passed to

AI-assisted analysis of symfony/var-dumper@e9d9cf5dcd (2026-09-14). Data as JSON: /api/errors/4b8b4778a91dfb0b. Report an issue: GitHub.

Appendix: source

Thrown at Cloner/Data.php:118

                    }
                    $recursive[$v->position] = true;
                }
                $children[$k] = $children[$k]->getValue($recursive);
            }
        }

        return $children;
    }

    public function count(): int
    {
        return \count($this->getValue());
    }

    public function getIterator(): \Traversable
    {
        if (!\is_array($value = $this->getValue())) {
            throw new \LogicException(\sprintf('"%s" object holds non-iterable type "%s".', self::class, get_debug_type($value)));
        }

        yield from $value;
    }

    public function __get(string $key): mixed
    {
        if (null !== $data = $this->seek($key)) {
            $item = $this->getStub($data->data[$data->position][$data->key]);

            return $item instanceof Stub || [] === $item ? $data : $item;
        }

        return null;
    }

    public function __isset(string $key): bool
    {

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