[Modular] update the collection behavior (#11963)

* only remove from the collection

src/diffusers/modular_pipelines/components_manager.py

@@ -386,6 +386,7 @@ class ComponentsManager:
                  id(component) is Python's built-in unique identifier for the object
         """
         component_id = f"{name}_{id(component)}"
+        is_new_component = True
 
         # check for duplicated components
         for comp_id, comp in self.components.items():
@@ -394,6 +395,7 @@ class ComponentsManager:
                 if comp_name == name:
                     logger.warning(f"ComponentsManager: component '{name}' already exists as '{comp_id}'")
                     component_id = comp_id
+                    is_new_component = False
                     break
                 else:
                     logger.warning(
@@ -426,7 +428,9 @@ class ComponentsManager:
                     logger.warning(
                         f"ComponentsManager: removing existing {name} from collection '{collection}': {comp_id}"
                     )
-                    self.remove(comp_id)
+                    # remove existing component from this collection (if it is not in any other collection, will be removed from ComponentsManager)
+                    self.remove_from_collection(comp_id, collection)
+
                 self.collections[collection].add(component_id)
                 logger.info(
                     f"ComponentsManager: added component '{name}' in collection '{collection}': {component_id}"
@@ -434,11 +438,29 @@ class ComponentsManager:
         else:
             logger.info(f"ComponentsManager: added component '{name}' as '{component_id}'")
 
-        if self._auto_offload_enabled:
+        if self._auto_offload_enabled and is_new_component:
             self.enable_auto_cpu_offload(self._auto_offload_device)
 
         return component_id
 
+    def remove_from_collection(self, component_id: str, collection: str):
+        """
+        Remove a component from a collection.
+        """
+        if collection not in self.collections:
+            logger.warning(f"Collection '{collection}' not found in ComponentsManager")
+            return
+        if component_id not in self.collections[collection]:
+            logger.warning(f"Component '{component_id}' not found in collection '{collection}'")
+            return
+        # remove from the collection
+        self.collections[collection].remove(component_id)
+        # check if this component is in any other collection
+        comp_colls = [coll for coll, comps in self.collections.items() if component_id in comps]
+        if not comp_colls:  # only if no other collection contains this component, remove it
+            logger.warning(f"ComponentsManager: removing component '{component_id}' from ComponentsManager")
+            self.remove(component_id)
+
     def remove(self, component_id: str = None):
         """
         Remove a component from the ComponentsManager.

src/diffusers/modular_pipelines/modular_pipeline_utils.py

@@ -185,6 +185,8 @@ class ComponentSpec:
         Unique identifier for this spec's pretrained load, composed of repo|subfolder|variant|revision (no empty
         segments).
         """
+        if self.default_creation_method == "from_config":
+            return "null"
         parts = [getattr(self, k) for k in self.loading_fields()]
         parts = ["null" if p is None else p for p in parts]
         return "|".join(p for p in parts if p)