Fix the default TaskHandle name for start() on Trio

The Trio backend computed final_name from func for the nursery, but
built the TaskHandle from the raw name argument, which is None by
default. The handle then derived its name from the internal wrapper
coroutine instead of func, so it lost the module qualifier and did not
match the task's own name.

The asyncio backend already spawns the handle with final_name, so the
two backends disagreed:

    asyncio  TaskHandle.name = '__main__.taskfunc'  (matches TaskInfo)
    trio     TaskHandle.name = 'taskfunc'           (does not)

Build the handle from final_name too. An explicit name argument was
already honoured and is unaffected.

Closes #1231

Author: dipakchaudhari12717

docs/versionhistory.rst

@@ -3,6 +3,13 @@ Version history
 
 This library adheres to `Semantic Versioning 2.0 <http://semver.org/>`_.
 
+**UNRELEASED**
+
+- Fixed the default ``TaskHandle.name`` of a task started with ``TaskGroup.start()`` on
+  Trio being taken from the internal wrapper coroutine, so it lacked the module
+  qualifier and disagreed with the task's own name
+  (`#1231 <https://github.com/agronholm/anyio/issues/1231>`_)
+
 **4.14.2**
 
 - Changed ``ByteReceiveStream.receive()`` implementations to raise a ``ValueError`` when

src/anyio/_backends/_trio.py

@@ -286,6 +286,11 @@ async def start(
     ) -> Any:
         handle: TaskHandle[T_co]
 
+        # Derived from func, not from the wrapper coroutine the handle is built
+        # around, so that TaskHandle.name matches the task's own name (and the
+        # asyncio backend, which spawns with this same name).
+        final_name = get_callable_name(func, name)
+
         async def run_coro_with_task_status(
             *, task_status: trio.TaskStatus[Any]
         ) -> None:
@@ -297,11 +302,10 @@ async def run_coro_with_task_status(
             else:
                 wrapper_task_status.real_task_status = task_status
 
-            handle = TaskHandle(coro, name)
+            handle = TaskHandle(coro, final_name)
             await handle._run_coro()
 
         self._check_active()
-        final_name = get_callable_name(func, name)
         start_value = await self._nursery.start(
             run_coro_with_task_status, name=final_name
         )

tests/test_taskgroups.py

@@ -1827,6 +1827,42 @@ async def taskfunc(*, task_status: TaskStatus[int]) -> int:
         assert handle.start_value == 3
 
 
+async def test_start_name_default() -> None:
+    """Like ``TestCreateTask.test_task_name_default``, but for ``start()``.
+
+    The handle used to be named after the wrapper coroutine on Trio, which
+    dropped the module qualifier and disagreed with the task's own name.
+    """
+
+    async def taskfunc(*, task_status: TaskStatus[None]) -> str | None:
+        task_status.started()
+        return get_current_task().name
+
+    expected = f"{__name__}.test_start_name_default.<locals>.taskfunc"
+    async with create_task_group() as tg:
+        handle = await tg.start(taskfunc, return_handle=True)
+        assert re.match(
+            rf"<TaskHandle (pending|finished) name='{re.escape(expected)}' "
+            r"coro=<coroutine object(.+)>>",
+            repr(handle),
+        )
+        assert await handle == handle.name
+
+    assert handle.name == expected
+
+
+async def test_start_name_custom_name() -> None:
+    async def taskfunc(*, task_status: TaskStatus[None]) -> str | None:
+        task_status.started()
+        return get_current_task().name
+
+    async with create_task_group() as tg:
+        handle = await tg.start(taskfunc, name="custom name", return_handle=True)
+        assert await handle == "custom name"
+
+    assert handle.name == "custom name"
+
+
 @pytest.mark.skipif(
     sys.implementation.name == "pypy",
     reason=(