phalcon/cphalcon · error · Phalcon\Support\Collection\Exceptions\ReadOnlyViolation

The object is read only

Error message

The object is read only

What it means

Phalcon\Support\Collection\ReadOnlyCollection is the immutable variant of Collection: it initializes once in the constructor and then all mutators are locked. clear() unconditionally throws Phalcon\Support\Collection\Exceptions\ReadOnlyViolation ("The object is read only") because wiping the data would mutate frozen state. The class exists so components can hand out safe, shareable views of data.

Solutions

1. Build a new object instead of clearing: $mutable = new Collection($readOnly->toArray()); then mutate the copy
2. Return a fresh empty instance if you need a 'cleared' value: new ReadOnlyCollection([])
3. Guard shared helpers: check instanceof ReadOnlyCollection before calling any mutator

Example fix

// before
$collection->clear(); // throws ReadOnlyViolation

// after
$collection = new Collection([]); // new instance, source untouched

use Phalcon\Support\Collection;
use Phalcon\Support\Collection\ReadOnlyCollection;

if ($collection instanceof ReadOnlyCollection) {
    $collection = new Collection($collection->toArray()); // mutable copy
}

$collection->clear();

function isReadOnlyCollection($collection): bool
{
    return $collection instanceof \Phalcon\Support\Collection\ReadOnlyCollection;
}

use Phalcon\Support\Collection\Exceptions\ReadOnlyViolation;

try {
    $collection->clear();
} catch (ReadOnlyViolation $e) {
    $collection = new \Phalcon\Support\Collection($collection->toArray());
}

When it happens

Trigger: Calling ->clear() on a ReadOnlyCollection obtained from a library or another component; reusing generic 'clear then repopulate' code written for the mutable Collection: $col->clear(); $col->init($newData);

Common situations: Library-returned value objects or shared config exposed as read-only on purpose. Generic collection utilities (cache reset, batch refresh) break when pointed at the immutable variant.

Related errors

• Row is an immutable ArrayAccess object
• The sort callback must be callable or null
• Value must be of type
• A dependency injection container is required to access…
• A dependency injection container is required to access the…

AI-assisted analysis of phalcon/cphalcon@b7419de9cd (2026-08-21). Data as JSON: /api/errors/1c5d3272e47c7c4d. Report an issue: GitHub.

Appendix: source

Thrown at phalcon/Support/Collection/ReadOnlyCollection.zep:73

        let this->constructed = false;

        try {
            parent::__unserialize(data);
        } catch \Throwable, ex {
            let this->constructed = true;

            throw ex;
        }

        let this->constructed = true;
    }

    /**
     * @throws ReadOnlyViolation
     */
    public function clear() -> void
    {
        throw new ReadOnlyViolation();
    }

    /**
     * @throws ReadOnlyViolation
     */
    public function init(array data = []) -> void
    {
        if (this->constructed) {
            throw new ReadOnlyViolation();
        }

        parent::init(data);
    }

    /**
     * Delete the element from the collection
     *
     * @throws ReadOnlyViolation

View on GitHub (pinned to b7419de9cd)