service: Avoid updating D-Bus nodes of devices tree

service/lib/agama/dbus/base_tree.rb

@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-# Copyright (c) [2023] SUSE LLC
+# Copyright (c) [2023-2024] SUSE LLC
 #
 # All Rights Reserved.
 #
@@ -47,11 +47,16 @@ def initialize(service, root_path, logger: nil)
       #
       # @param objects [Array]
       def objects=(objects)
-        try_add_objects(objects)
         try_update_objects(objects)
+        try_add_objects(objects)
         try_delete_objects(objects)
       end
 
+      # Unexports the current D-Bus objects of this tree.
+      def clean
+        dbus_objects.each { |o| service.unexport(o) }
+      end
+
     private
 
       # @return [::DBus::ObjectServer]

service/lib/agama/dbus/storage/device.rb

@@ -30,8 +30,15 @@ module Storage
       #
       # The D-Bus object includes the required interfaces for the storage object that it represents.
       class Device < BaseObject
-        # @return [Y2Storage::Device]
-        attr_reader :storage_device
+        # sid of the Y2Storage device.
+        #
+        # @note A Y2Storage device is a wrapper over a libstorage-ng object. If the source
+        #   devicegraph does not exist anymore (e.g., after reprobing), then the Y2Storage device
+        #   object cannot be used (memory error). The device sid is stored to avoid accessing to
+        #   the old Y2Storage device when updating the represented device, see {#storage_device=}.
+        #
+        # @return [Integer]
+        attr_reader :sid
 
         # Constructor
         #
@@ -43,6 +50,7 @@ def initialize(storage_device, path, tree, logger: nil)
           super(path, logger: logger)
 
           @storage_device = storage_device
+          @sid = storage_device.sid
           @tree = tree
           add_interfaces
         end
@@ -54,12 +62,13 @@ def initialize(storage_device, path, tree, logger: nil)
         #
         # @param value [Y2Storage::Device]
         def storage_device=(value)
-          if value.sid != storage_device.sid
+          if value.sid != sid
             raise "Cannot update the D-Bus object because the given device has a different sid: " \
-                  "#{value} instead of #{storage_device.sid}"
+                  "#{value} instead of #{sid}"
           end
 
           @storage_device = value
+          @sid = value.sid
 
           interfaces_and_properties.each do |interface, properties|
             dbus_properties_changed(interface, properties, [])
@@ -71,6 +80,9 @@ def storage_device=(value)
         # @return [DevicesTree]
         attr_reader :tree
 
+        # @return [Y2Storage::Device]
+        attr_reader :storage_device
+
         # Adds the required interfaces according to the storage object.
         def add_interfaces
           interfaces = Interfaces::Device.constants

service/lib/agama/dbus/storage/devices_tree.rb

@@ -36,10 +36,19 @@ def path_for(device)
           ::DBus::ObjectPath.new(File.join(root_path, device.sid.to_s))
         end
 
-        # Updates the D-Bus tree according to the given devicegraph
+        # Updates the D-Bus tree according to the given devicegraph.
+        #
+        # @note In the devices tree it is important to avoid updating D-Bus nodes. Note that an
+        #   already exported D-Bus object could require to add or remove interfaces (e.g., an
+        #   existing partition needs to add the Filesystem interface after formatting the
+        #   partition). Dynamically adding or removing intefaces is not possible with ruby-dbus
+        #   once the object is exported on D-Bus.
+        #
+        #   Updating the currently exported D-Bus objects is avoided by calling to {#clean} first.
         #
         # @param devicegraph [Y2Storage::Devicegraph]
         def update(devicegraph)
+          clean
           self.objects = devices(devicegraph)
         end
 
@@ -52,17 +61,17 @@ def create_dbus_object(device)
         end
 
         # @see BaseTree
-        # @param dbus_object [Device]
-        # @param device [Y2Storage::Device]
-        def update_dbus_object(dbus_object, device)
-          dbus_object.storage_device = device
+        #
+        # @note D-Bus objects representing devices cannot be safely updated, see {#update}.
+        def update_dbus_object(_dbus_object, _device)
+          nil
         end
 
         # @see BaseTree
         # @param dbus_object [Device]
         # @param device [Y2Storage::Device]
         def dbus_object?(dbus_object, device)
-          dbus_object.storage_device.sid == device.sid
+          dbus_object.sid == device.sid
         end
 
         # Devices to be exported.

service/test/agama/dbus/storage/device_test.rb

@@ -181,12 +181,6 @@
     context "if the given device has the same sid" do
       let(:new_device) { devicegraph.find_by_name("/dev/sda") }
 
-      it "sets the new device" do
-        subject.storage_device = new_device
-
-        expect(subject.storage_device).to equal(new_device)
-      end
-
       it "emits a properties changed signal for each interface" do
         subject.interfaces_and_properties.each_key do |interface|
           expect(subject).to receive(:dbus_properties_changed).with(interface, anything, anything)