chore: test if agents are mergeable

testing for object equality is too strict, and it fails on tests
of 'reuses an existing network', because the agents are created in
different cyles

lib/syskit/network_generation/merge_solver.rb

@@ -242,7 +242,8 @@ def mergeable_agents?(merged_task, task)
 
                 return false unless merge_when_identical_agents?
 
-                return true if task.execution_agent == merged_task.execution_agent
+                return true if task.execution_agent
+                                   .can_merge?(merged_task.execution_agent)
 
                 false
             end

lib/syskit/network_generation/system_network_deployer.rb

@@ -56,15 +56,15 @@ def initialize(plan,
             #   will run on the generated network
             # @return [Set] the set of tasks for which the deployer could
             #   not find a deployment
-            def deploy(validate: true, reuse_deployments: false, deployment_tasks: {})
+            def deploy(validate: true, reuse_deployments: false)
                 debug "Deploying the system network"
 
                 all_tasks = plan.find_local_tasks(TaskContext).to_a
                 selected_deployments, missing_deployments =
                     select_deployments(all_tasks, reuse: reuse_deployments)
                 log_timepoint "select_deployments"
 
-                apply_selected_deployments(selected_deployments, deployment_tasks)
+                apply_selected_deployments(selected_deployments)
                 log_timepoint "apply_selected_deployments"
 
                 if validate
@@ -167,7 +167,8 @@ def select_deployments(tasks, reuse: false)
             # @param [Component=>Deployment] selected_deployments the
             #   component-to-deployment association
             # @return [void]
-            def apply_selected_deployments(selected_deployments, deployment_tasks = {})
+            def apply_selected_deployments(selected_deployments)
+                deployment_tasks = {}
                 selected_deployments.each do |task, deployed_task|
                     deployed_task, = deployed_task.instanciate(
                         plan,

lib/syskit/network_generation/system_network_generator.rb

@@ -209,16 +209,15 @@ def self.remove_abstract_composition_optional_children(plan)
                 end
             end
 
-            def deploy(deployment_tasks)
+            def deploy
                 network_deployer = SystemNetworkDeployer.new(
                     plan,
                     merge_solver: merge_solver,
                     default_deployment_group: default_deployment_group
                 )
 
                 missing = network_deployer.deploy(validate: false,
-                                                  reuse_deployments: true,
-                                                  deployment_tasks: deployment_tasks)
+                                                  reuse_deployments: true)
                 network_deployer.verify_all_tasks_deployed if validate_deployed_network?
 
                 raise unless missing.empty? # TODO
@@ -237,9 +236,7 @@ def compute_system_network(instance_requirements, garbage_collect: true,
 
                 @toplevel_instance_requirements = instance_requirements
 
-                deployment_tasks = {}
-
-                deploy(deployment_tasks) if early_deploy?
+                deploy if early_deploy?
 
                 merge_identical_tasks
                 log_timepoint "merge"
@@ -250,7 +247,7 @@ def compute_system_network(instance_requirements, garbage_collect: true,
                 link_to_busses
                 log_timepoint "link_to_busses"
 
-                deploy(deployment_tasks) if early_deploy?
+                deploy if early_deploy?
 
                 merge_identical_tasks