Ensure async generators are awaited (open-telemetry#2792)

CHANGELOG.md

@@ -29,6 +29,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
   ([#2589](https://github.com/open-telemetry/opentelemetry-python-contrib/pull/2589))
 - `opentelemetry-instrumentation-celery` propagates baggage
   ([#2385](https://github.com/open-telemetry/opentelemetry-python-contrib/pull/2385))
+- `opentelemetry-instrumentation-asyncio` Fixes async generator coroutines not being awaited
+  ([#2792](https://github.com/open-telemetry/opentelemetry-python-contrib/pull/2792))
 
 ## Version 1.26.0/0.47b0 (2024-07-23)
 

instrumentation/opentelemetry-instrumentation-asyncio/src/opentelemetry/instrumentation/asyncio/__init__.py

@@ -262,7 +262,7 @@ def trace_item(self, coro_or_future):
 
     async def trace_coroutine(self, coro):
         if not hasattr(coro, "__name__"):
-            return coro
+            return await coro
         start = default_timer()
         attr = {
             "type": "coroutine",

instrumentation/opentelemetry-instrumentation-asyncio/tests/test_asyncio_anext.py

@@ -43,19 +43,23 @@ def tearDown(self):
 
     # Asyncio anext() does not have __name__ attribute, which is used to determine if the coroutine should be traced.
     # This test is to ensure that the instrumentation does not break when the coroutine does not have __name__ attribute.
+    # Additionally, ensure the coroutine is actually awaited.
     @skipIf(
         sys.version_info < (3, 10), "anext is only available in Python 3.10+"
     )
     def test_asyncio_anext(self):
         async def main():
             async def async_gen():
-                for it in range(2):
+                # nothing special about this range other than to avoid returning a zero
+                # from a function named 'main' (which might cause confusion about intent)
+                for it in range(2, 4):
                     yield it
 
             async_gen_instance = async_gen()
             agen = anext(async_gen_instance)
-            await asyncio.create_task(agen)
+            return await asyncio.create_task(agen)
 
-        asyncio.run(main())
+        ret = asyncio.run(main())
+        self.assertEqual(ret, 2)  # first iteration from range()
         spans = self.memory_exporter.get_finished_spans()
         self.assertEqual(len(spans), 0)