fix(async): make wrapper clear methods await-safe for coroutine-decorated functions

clear_cache/clear_being_calculated on async-decorated wrappers
previously returned None, so await func.clear_cache() raised TypeError.
Return an immediate awaitable for coroutine wrappers while preserving
existing sync usage, and add a regression test covering both sync and
awaited calls.

Author: shaypal5

src/cachier/core.py

@@ -35,6 +35,18 @@
 ZERO_TIMEDELTA = timedelta(seconds=0)
 
 
+class _ImmediateAwaitable:
+    """Lightweight awaitable that yields an immediate value."""
+
+    def __init__(self, value: Any = None) -> None:
+        self._value = value
+
+    def __await__(self):
+        if False:
+            yield None
+        return self._value
+
+
 def _max_workers():
     return int(os.environ.get(MAX_WORKERS_ENVAR_NAME, DEFAULT_MAX_WORKERS))
 
@@ -593,10 +605,16 @@ def func_wrapper(*args, **kwargs):
         def _clear_cache():
             """Clear the cache."""
             core.clear_cache()
+            if is_coroutine:
+                return _ImmediateAwaitable()
+            return None
 
         def _clear_being_calculated():
             """Mark all entries in this cache as not being calculated."""
             core.clear_being_calculated()
+            if is_coroutine:
+                return _ImmediateAwaitable()
+            return None
 
         async def _aclear_cache():
             """Clear the cache asynchronously."""

tests/test_async_core.py

@@ -358,6 +358,27 @@ def sync_func(x):
         await sync_func.aclear_cache()
 
 
+@pytest.mark.memory
+@pytest.mark.asyncio
+class TestAsyncWrapperMaintenanceMethods:
+    """Tests for clear helpers exposed on async wrappers."""
+
+    async def test_clear_methods_are_await_safe(self):
+        """Async wrappers support both sync and awaited clear_cache usage."""
+
+        @cachier(backend="memory")
+        async def async_func(x):
+            return x
+
+        # Legacy sync usage should keep working.
+        async_func.clear_cache()
+        async_func.clear_being_calculated()
+
+        # Awaiting these methods should also work.
+        await async_func.clear_cache()
+        await async_func.clear_being_calculated()
+
+
 # =============================================================================
 # Argument Handling Tests
 # =============================================================================