Raise ExceptionGroup in PendingGroup when a pending fails.

src/async_kernel/pending.py

@@ -206,6 +206,7 @@ class PendingGroup(PendingTracker, anyio.AsyncContextManagerMixin):
     _cancel_scope: anyio.CancelScope
     _cancelled: str | None = None
     _leaving_context: bool = False
+    _failed: Fixed[Self, list[Pending]] = Fixed(list)
     cancellation_timeout = 10
     "The maximum time to wait for cancelled pending to be done."
 
@@ -236,7 +237,9 @@ async def __asynccontextmanager__(self) -> AsyncGenerator[Self]:
                     self.cancel(f"An error occurred: {e!r}")
                     raise
             if self._cancelled is not None:
-                raise PendingCancelled(self._cancelled)
+                exceptions = [e for pen in self._failed if isinstance(e := pen.exception(), Exception)]
+                msg = "One or more exceptions occurred in this context!"
+                raise ExceptionGroup(msg, exceptions)
         finally:
             self._leaving_context = True
             self._stop_tracking(token)
@@ -261,6 +264,7 @@ def on_pending_done(self, pen: Pending) -> None:
         try:
             self._pending.remove(pen)
             if self._active and (not pen.cancelled() and (pen.exception())):
+                self._failed.append(pen)
                 self.cancel(f"Exception in member: {pen}")
         except KeyError:
             pass

tests/test_pending.py

@@ -420,14 +420,14 @@ async def add_when_cancelled():
         assert not pm.active
 
     async def test_wait_exception(self, caller: Caller):
-        with pytest.raises(PendingCancelled):  # noqa: PT012
+        with pytest.raises(ExceptionGroup):  # noqa: PT012
             async with PendingGroup():
                 pen = caller.call_soon(anyio.sleep_forever)
                 Pending(PendingGroup).set_exception(RuntimeError("stop"))
         assert pen.cancelled()  # pyright: ignore[reportPossiblyUnboundVariable]
 
     async def test_cancelled_by_pending(self, caller: Caller):
-        with pytest.raises(PendingCancelled):  # noqa: PT012
+        with pytest.raises(ExceptionGroup):  # noqa: PT012
             async with PendingGroup() as pg:
                 assert caller.call_soon(lambda: 1 / 0) in pg.pending
                 await anyio.sleep_forever()
@@ -473,11 +473,9 @@ async def test_nested(self, caller: Caller):
         assert pen.cancelled()  # pyright: ignore[reportPossiblyUnboundVariable]
 
     async def test_nested_raises(self, caller: Caller):
-        with pytest.raises(PendingCancelled, match="division by zero"):  # noqa: PT012
-            async with caller.create_pending_group() as pg1:
-                async with pg1.caller.create_pending_group() as pg2:
-                    pen = pg2.caller.call_soon(lambda: 1 / 0)
-
+        with pytest.raises(ExceptionGroup):
+            async with caller.create_pending_group() as pg1, pg1.caller.create_pending_group() as pg2:
+                pen = pg2.caller.call_soon(lambda: 1 / 0)
         assert pen.exception()  # pyright: ignore[reportPossiblyUnboundVariable]
 
     async def test_queue(self, caller: Caller):