[12.x] Fix/memory improvement

[CharrafiMed]

Fix memory leak in Blade @props directive

Problem

While investigating Blade's compilation process for a project bridging Blade and Alpine.js, I discovered a memory leak in the @props directive. The temporary variables $__key and $__value from foreach loops are not cleaned up after compilation. These variables persist in component scope, holding references to the last processed data attribute.

Impact:

• Laravel Octane: Memory accumulates across requests
• Queue workers: References build up during batch processing
• Long-running processes: Large objects never get freed

Example scenario:

<div x-data="{ tags: ['php','js'] }">
    <x-tags-input
        x-model="tags"
        placeholder="Add tags..."
        :langs="['arabic','french','english']"
        :suggestions="$largeDatasetArray" 
    />
</div>

Using get_defined_vars() to debug component scope reveals:

• $__key holds "suggestions"
• $__value holds the entire $largeDatasetArray array

If this component is the last processed in a request, these references persist indefinitely in long-running environments.

Solution

Add cleanup for temporary variables in the compileProps() method:

// Before:
unset($__defined_vars); ?>";

// After:  
unset($__defined_vars, $__key, $__value); ?>";

Benefits

• Improved memory efficiency for Octane and queue-based applications
• Zero breaking changes - only removes variables that shouldn't persist
• Automatic improvement for all applications using @props
• Identical functional behavior - compilation output unchanged except for cleanup

Testing

• All existing Blade tests continue to pass
• Added test case to verify temporary variable cleanup
• Confirmed compiled output is functionally identical except for additional cleanup