How to create a stable cache key from function arguments in Python

import hashlib
import json
from unittest.mock import Mock


def make_cache_key(*args, **kwargs):
    """Normalize args/kwargs into a stable hash key for caching."""
    normalized = {
        "args": [repr(arg) for arg in args],
        "kwargs": {key: repr(value) for key, value in sorted(kwargs.items())}
    }
    payload = json.dumps(normalized, sort_keys=True)
    return hashlib.sha256(payload.encode()).hexdigest()


def cached_result(call_count):
    """Simple demo returning a result the mock will cache."""
    return f"result-{call_count}"


if __name__ == "__main__":
    mock_cache = Mock()
    mock_cache.get.return_value = None

    key1 = make_cache_key(42, "hello", foo="bar", count=3)
    key2 = make_cache_key(42, "hello", count=3, foo="bar")
    key3 = make_cache_key(43, "hello", foo="bar", count=3)

    print(f"key1: {key1}")
    print(f"key2: {key2}")
    print(f"key3: {key3}")
    print(f"key1 == key2 (same args, different order): {key1 == key2}")
    print(f"key1 == key3 (different arg): {key1 == key3}")