Type Mismatch in Polymorphic Relationships When Using PostgreSQL

[mathiasgrimm]

Laravel Version

11.x

PHP Version

8.4

Database Driver & Version

pgsql 17

Description

Type Mismatch in Polymorphic Relationships When Using PostgreSQL

Description

When using polymorphic relationships with PostgreSQL, there's a type mismatch issue between the parent model's ID (integer) and the morphed model's foreign key (string). This occurs because the getKeyType() method always returns 'int' for regular incrementing IDs, while the morphed table's foreign key is defined as a string.

Current Behavior

The query fails with the following PostgreSQL error:

SQLSTATE[42883]: Undefined function: 7 ERROR: operator does not exist: character varying = integer
LINE 1: ...om "integrations" where "integrations"."owner_id" in (1) and...
^
HINT: No operator matches the given name and argument types. You might need to add explicit type casts.

Database Schema

Integrations Table

Schema::create('integrations', function (Blueprint $table) {
    $table->id();
    $table->string('owner_type');
    $table->string('owner_id'); // Defined as string
    $table->string('provider');
    $table->timestamps();
});

Users Table

Schema::create('users', function (Blueprint $table) {
    $table->id(); // Integer type
    // ... other columns
});

Model Relationships

User Model

public function integrations(): MorphMany
{
    return $this->morphMany(Integration::class, 'owner');
}

Integration Model

public function owner(): MorphTo
{
    return $this->morphTo('owner');
}

Expected Behavior

The polymorphic relationship should handle the type casting between the integer primary key of the parent model and the string foreign key in the morphed table when using PostgreSQL.

Possible Solution

Consider implementing automatic type casting for morphed foreign keys based on the column type, rather than relying solely on the parent model's getKeyType() method.

Additional Context

• This issue specifically affects PostgreSQL due to its strict type checking
• MySQL handles this scenario without errors due to implicit type conversion
• The getKeyType() method currently only returns 'string' for UUID keys, defaulting to 'int' for all other cases

Tags

• Bug
• PostgreSQL
• Eloquent
• Polymorphic Relationships

Steps To Reproduce

Steps to Reproduce

1. Create the database tables:

// Create users table
Schema::create('users', function (Blueprint $table) {
    $table->id();
    $table->string('name');
    $table->string('email')->unique();
    $table->timestamps();
});

// Create integrations table
Schema::create('integrations', function (Blueprint $table) {
    $table->id();
    $table->string('owner_type');
    $table->string('owner_id');
    $table->string('provider');
    $table->timestamps();
});

2. Set up the models:

// User.php
class User extends Model
{
    public function integrations(): MorphMany
    {
        return $this->morphMany(Integration::class, 'owner');
    }
}

// Integration.php
class Integration extends Model
{
    public function owner(): MorphTo
    {
        return $this->morphTo('owner');
    }
}

3. Create a test user:

$user = User::create([
    'name' => 'Test User',
    'email' => 'test@example.com'
]);

4. Try to query the integrations for the user:

// This will trigger the error
$integrations = Integration::where('owner_id', $user->id)
    ->where('owner_type', User::class)
    ->get();

// Or alternatively, this will also trigger the error
$userIntegrations = $user->integrations()->get();

5. Observe the PostgreSQL error:

SQLSTATE[42883]: Undefined function: 7 ERROR: operator does not exist: character varying = integer
LINE 1: ...om "integrations" where "integrations"."owner_id" in (1) and...
^
HINT: No operator matches the given name and argument types. You might need to add explicit type casts.

Environment:

• Laravel Framework (latest version)
• PostgreSQL database
• PHP 8.x

The error occurs specifically with PostgreSQL due to its strict type checking between string and integer comparisons. The same code works in MySQL due to implicit type conversion.

[mathiasgrimm]

Additional context:

An important consideration for the solution is that we need to selectively define which polymorphic relationships should use string foreign keys. In this case, while the User-Integration relationship needs owner_id as a string, other polymorphic relationships on the same model might need to keep using integer IDs. Therefore, we need a way to configure the foreign key type on a per-relationship basis.

I was able to achieve it using the following workaround on the User model:

protected $idAsString = false;

public function integrations(): MorphMany
{
    $this->idAsString = true;
    $value = $this->morphMany(Integration::class, 'owner');

    return $value;
}

public function getKeyType()
{
    if ($this->idAsString) {
        $this->idAsString = false;
        return 'string';
    }

    return parent::getKeyType();
}

A potential solution could be implementing an array configuration like:

$foreignKeyTypes = [
    'integrations' => 'string',
];

This would allow the model to know when it needs to use string for specific relationships.