🎨 Improves empty-trash to avoid misleading the user (#7267)

Author: pcrespov

services/web/server/src/simcore_service_webserver/trash/_rest.py

@@ -1,3 +1,4 @@
+import asyncio
 import logging
 
 from aiohttp import web
@@ -20,10 +21,6 @@
 
 _logger = logging.getLogger(__name__)
 
-#
-# EXCEPTIONS HANDLING
-#
-
 
 _TO_HTTP_ERROR_MAP: ExceptionToHttpErrorMap = {
     ProjectRunningConflictError: HttpErrorInfo(
@@ -42,10 +39,6 @@
 )
 
 
-#
-# ROUTES
-#
-
 routes = web.RouteTableDef()
 
 
@@ -57,12 +50,24 @@ async def empty_trash(request: web.Request):
     user_id = get_user_id(request)
     product_name = get_product_name(request)
 
-    fire_and_forget_task(
-        _service.safe_empty_trash(
+    is_fired = asyncio.Event()
+
+    async def _empty_trash():
+        is_fired.set()
+        await _service.safe_empty_trash(
             request.app, product_name=product_name, user_id=user_id
-        ),
+        )
+
+    fire_and_forget_task(
+        _empty_trash(),
         task_suffix_name="rest.empty_trash",
         fire_and_forget_tasks_collection=request.app[APP_FIRE_AND_FORGET_TASKS_KEY],
     )
 
+    # NOTE: Ensures `fire_and_forget_task` is triggered; otherwise,
+    # when the front-end requests the trash item list,
+    # it may still display items, misleading the user into
+    # thinking the `empty trash` operation failed.
+    await is_fired.wait()
+
     return web.json_response(status=status.HTTP_204_NO_CONTENT)