workaround: disable some offline upgrade code, update only packages

the offline migration code does DUP from all, online migration
needs to do only DUP from the migration repositories

.rubocop.yml

@@ -1,3 +1,8 @@
 # use the shared Yast defaults
 inherit_from:
   /usr/share/YaST2/data/devtools/data/rubocop_yast_style.yml
+
+Style/MethodName:
+  Exclude:
+  # the mocked Update module methods break the Ruby naming rule
+  - test/main_workflow_test.rb

src/lib/migration/main_workflow.rb

@@ -105,6 +105,14 @@ def repositories
     end
 
     def proposals
+      # HACK: disable updating from _all_ repositories in update_proposal.rb
+      # client, pretend that the initialization has been already done
+      Yast::Update.did_init1 = true
+
+      # update only installed packages, updated based on patterns is used for
+      # product version upgrade (e.g. SLES11 -> SLES12)
+      Yast::Update.onlyUpdateInstalled = true
+
       Yast::WFM.CallFunction("migration_proposals")
     end
 

test/main_workflow_test.rb

@@ -22,9 +22,10 @@
 module Yast
   # Faked Update module
   class UpdateClass
-    # we need at least one non-default methods, otherwise ruby-bindings thinks
-    # it is just namespace
-    def fake_method
+    def did_init1=(_init)
+    end
+
+    def onlyUpdateInstalled=(_mode)
     end
   end
   Update = UpdateClass.new