fix: add more information on the network generation application result

Now that we can capture errors, we have to add more information on the
result of the application of the generated network to the plan. This is
done by changing the return of #syskit_apply_resolution_results to a
struct that has information of the errors and the planned instances.

lib/syskit/network_generation/async.rb

@@ -119,9 +119,6 @@ def cancelled?
 
             class InvalidState < RuntimeError; end
 
-            SystemNetworkPlanApplyResult =
-                Struct.new :fulfilled, :instances, :errors, keyword_init: true
-
             # Apply the result of the generation
             #
             # @return [Boolean] true if the result has been applied, and false

lib/syskit/network_generation/resolution_error_handler.rb

@@ -11,6 +11,14 @@ def initialize(errors)
             end
         end
 
+        # Reports the result of the network generation application.
+        SystemNetworkPlanApplyResult =
+            Struct.new :fulfilled, :instances, :errors, keyword_init: true do
+                def fulfilled?
+                    fulfilled
+                end
+            end
+
         # This is used to capture failures during the network generation process. Each
         # failure bundles the toplevel tasks that are related to the task that originates
         # the failure. It should be transformed into a ResolutionError for each related

lib/syskit/runtime/apply_requirement_modifications.rb

@@ -103,7 +103,10 @@ def syskit_apply_async_resolution_results
 
                 begin
                     resolution_apply_result = syskit_current_resolution.apply
-                    return unless resolution_apply_result.fulfilled
+
+                    unless resolution_apply_result.fulfilled?
+                        return resolution_apply_result
+                    end
                 ensure
                     syskit_current_resolution_keepalive.discard_transaction
                     @syskit_current_resolution = nil
@@ -115,12 +118,14 @@ def syskit_apply_async_resolution_results
                 resolution_apply_result.errors.group_by(&:planning_task).each do |task, e|
                     task.failed_event.emit e.flat_map(&:original_exception)
                 end
-                nil
+                resolution_apply_result
             rescue ::Exception => e # rubocop:disable Lint/RescueException
                 running_requirement_tasks.each do |t|
                     t.failed_event.emit(e)
                 end
-                e
+                NetworkGeneration::SystemNetworkPlanApplyResult.new(
+                    fulfilled: false, errors: [e]
+                )
             end
         end
 

lib/syskit/test/instance_requirement_planning_handler.rb

@@ -56,17 +56,17 @@ def apply_requirements
                 )
             end
 
-            def finished?
+            def finished? # rubocop:disable Metrics/AbcSize
                 Thread.pass
 
                 if @plan.syskit_has_async_resolution?
                     return unless @plan.syskit_finished_async_resolution?
 
-                    error = @plan.syskit_apply_async_resolution_results
-                    return true if error
+                    resolution_results = @plan.syskit_apply_async_resolution_results
+                    return true unless resolution_results.fulfilled?
                     return unless @test.syskit_run_planner_stub?
 
-                    root_tasks = @planning_tasks.map(&:planned_task)
+                    root_tasks = resolution_results.instances.keys.map(&:planned_task)
                     stub_network = StubNetwork.new(@test)
 
                     # NOTE: this is a run-planner equivalent to syskit_stub_network