Fix cloudcomputes registration for structures (#15964)

* fix cloudcomputes
* updates cloudcompute registration
* changelog

(cherry picked from commit 90a4c02)

src/lightning_app/CHANGELOG.md

@@ -55,6 +55,7 @@ The format is based on [Keep a Changelog](http://keepachangelog.com/en/1.0.0/).
 - Fixed detection of a Lightning App running in debug mode ([#15951](https://github.com/Lightning-AI/lightning/pull/15951))
 - Fixed `ImportError` on Multinode if package not present ([#15963](https://github.com/Lightning-AI/lightning/pull/15963))
 - Fixed MultiNode Component to use separate cloud computes ([#15965](https://github.com/Lightning-AI/lightning/pull/15965))
+- Fixed Registration for CloudComputes of Works in `L.app.structures` ([#15964](https://github.com/Lightning-AI/lightning/pull/15964))
 
 
 ## [1.8.3] - 2022-11-22

src/lightning_app/core/flow.py

@@ -173,12 +173,19 @@ def __setattr__(self, name: str, value: Any) -> None:
             elif isinstance(value, (Dict, List)):
                 self._structures.add(name)
                 _set_child_name(self, value, name)
-                if getattr(self, "_backend", None) is not None:
-                    value._backend = self._backend
-                    for flow in value.flows:
-                        LightningFlow._attach_backend(flow, self._backend)
-                    for work in value.works:
-                        self._backend._wrap_run_method(_LightningAppRef().get_current(), work)
+
+                _backend = getattr(self, "backend", None)
+                if _backend is not None:
+                    value._backend = _backend
+
+                for flow in value.flows:
+                    if _backend is not None:
+                        LightningFlow._attach_backend(flow, _backend)
+
+                for work in value.works:
+                    work._register_cloud_compute()
+                    if _backend is not None:
+                        _backend._wrap_run_method(_LightningAppRef().get_current(), work)
 
             elif isinstance(value, Path):
                 # In the init context, the full name of the Flow and Work is not known, i.e., we can't serialize

tests/tests_app/core/test_lightning_flow.py

@@ -10,7 +10,8 @@
 import pytest
 from deepdiff import DeepDiff, Delta
 
-from lightning_app import LightningApp
+import lightning_app
+from lightning_app import CloudCompute, LightningApp
 from lightning_app.core.flow import LightningFlow
 from lightning_app.core.work import LightningWork
 from lightning_app.runners import MultiProcessRuntime
@@ -901,3 +902,29 @@ def run_patch(method):
     state = app.api_publish_state_queue.put._mock_call_args[0][0]
     call_hash = state["works"]["w"]["calls"]["latest_call_hash"]
     assert state["works"]["w"]["calls"][call_hash]["statuses"][0]["stage"] == "succeeded"
+
+
+def test_structures_register_work_cloudcompute():
+    class MyDummyWork(LightningWork):
+        def run(self):
+            return
+
+    class MyDummyFlow(LightningFlow):
+        def __init__(self):
+            super().__init__()
+            self.w_list = LList(*[MyDummyWork(cloud_compute=CloudCompute("gpu")) for i in range(5)])
+            self.w_dict = LDict(**{str(i): MyDummyWork(cloud_compute=CloudCompute("gpu")) for i in range(5)})
+
+        def run(self):
+            for w in self.w_list:
+                w.run()
+
+            for w in self.w_dict.values():
+                w.run()
+
+    MyDummyFlow()
+    assert len(lightning_app.utilities.packaging.cloud_compute._CLOUD_COMPUTE_STORE) == 10
+    for v in lightning_app.utilities.packaging.cloud_compute._CLOUD_COMPUTE_STORE.values():
+        assert len(v.component_names) == 1
+        assert v.component_names[0][:-1] in ("root.w_list.", "root.w_dict.")
+        assert v.component_names[0][-1].isdigit()