list_append_perf_test.py

# From https://github.com/python/cpython/issues/132917
import itertools
import time

def performance_test(n_options=5, n_items=5, iterations=50):
    list = []
    
    def expensive_operation():
        # Create lists of tuples
        data = []
        for _ in range(n_options):
            data.append([(f"a{i}", f"b{i}") for i in range(n_items)])
        
        # Generate all combinations and create result tuples
        results = []
        for combo in itertools.product(*data):
            result = tuple((x[0], x[1], f"name_{i}") for i, x in enumerate(combo))
            results.append(result)
        
        # Commenting the following line solves the performance regression in free-threaded mode
        list.append(results)
        return results

    start = time.time()
    for _ in range(iterations):
        result = expensive_operation()
    
    duration = time.time() - start
    print(f"n_options={n_options}, n_items={n_items}, iterations={iterations}")
    print(f"Time: {duration:.4f}s, Combinations: {len(result)}")
    return duration

if __name__ == "__main__":
    print("Python Performance Regression Test")
    print("-" * 40)
    performance_test()