Migration-based property handlers don't recognize property writes (sealAllProperties)

[alies-dev]

Summary

ModelPropertyHandler::doesPropertyExist() (and ModelPropertyAccessorHandler, ModelRelationshipPropertyHandler) only handle read mode — they return null for write operations. This means migration-inferred properties are never recognized for assignments like $model->property = value.

Combined with sealAllProperties="true", this causes UndefinedMagicPropertyAssignment / UndefinedThisPropertyAssignment errors on every model property write for models that rely on migration-based schema inference (i.e., models without explicit @property PHPDoc).

Steps to reproduce

1. Configure sealAllProperties="true" in psalm.xml
2. Create a model without @property annotations (relying on migration-based inference)
3. Write to a model property:

$model->published_at = now();
// or inside the model:
$this->published_at = now();

4. Run Psalm

Expected behavior

The property should be recognized as valid since it exists in the migration schema.

Actual behavior

ERROR: UndefinedMagicPropertyAssignment
Magic instance property App\MyModel::$published_at is not defined

Root cause

In ModelPropertyHandler::doesPropertyExist():

public static function doesPropertyExist(PropertyExistenceProviderEvent $event): ?bool
{
    if (!$event->isReadMode()) {
        return null; // ← skips all writes, so the property is "unknown" to Psalm
    }
    // ...
}

The same pattern exists in ModelPropertyAccessorHandler::doesPropertyExist() and ModelRelationshipPropertyHandler.

Returning null means "I don't know about this property", so Psalm falls back to its default sealed-class behavior and reports the property as undefined.

Suggested fix

Remove or relax the isReadMode() guard in doesPropertyExist() so that migration-inferred columns are recognized for both reads and writes:

public static function doesPropertyExist(PropertyExistenceProviderEvent $event): ?bool
{
    // Handle both reads and writes for migration-inferred properties
    // ...
    $column = self::resolveColumn($fqClasslikeName, $propertyName);
    if ($column instanceof SchemaColumn) {
        return true;
    }
    return null;
}

Note: The isReadMode() guard should remain in getPropertyType() and isPropertyVisible() since those only apply to reads.

Workaround

Add @property PHPDoc annotations to the model — these are handled natively by Psalm for both reads and writes.

[alies-dev]

fixed