fix(runtime): guard sync API when called from async context (closes #1085)

Author: samojavo

python/cocoindex/runtime.py

@@ -8,7 +8,7 @@
 import inspect
 import warnings
 
-from typing import Any, Callable, Awaitable, TypeVar
+from typing import Any, Callable, Awaitable, TypeVar, Coroutine
 
 T = TypeVar("T")
 
@@ -35,7 +35,7 @@ def _runner(l: asyncio.AbstractEventLoop) -> None:
                 threading.Thread(target=_runner, args=(loop,), daemon=True).start()
             return self._event_loop
 
-    def run(self, coro):
+    def run(self, coro: Coroutine[Any, Any, T]) -> T:
         """Run a coroutine in the event loop, blocking until it finishes. Return its result."""
         try:
             running_loop = asyncio.get_running_loop()
@@ -69,4 +69,4 @@ def run(self, coro):
 def to_async_call(call: Callable[..., Any]) -> Callable[..., Awaitable[Any]]:
     if inspect.iscoroutinefunction(call):
         return call
-    return lambda *args, **kwargs: asyncio.to_thread(lambda: call(*args, **kwargs))
+    return lambda *args, **kwargs: asyncio.to_thread(lambda: call(*args, **kwargs))