turn the method into a protected one

app/models/work_package.rb

@@ -124,7 +124,7 @@ class WorkPackage < ActiveRecord::Base
 
   include OpenProject::NestedSet::WithRootIdScope
 
-  after_save :reschedule_following_issues,
+  after_save :reschedule_following_work_packages,
              :update_parent_attributes
 
   after_move :remove_invalid_relations,
@@ -369,27 +369,6 @@ class WorkPackage < ActiveRecord::Base
     ).compact.max
   end
 
-  # Updates start/due dates of following issues
-  def reschedule_following_issues
-    delta = date_rescheduling_delta
-
-    if delta < 0
-      relations_from.each { |r| r.move_target_dates_by(delta) }
-    elsif start_date_changed? || due_date_changed?
-      relations_from.each(&:set_dates_of_target)
-    end
-  end
-
-  def date_rescheduling_delta
-    if due_date.present?
-      due_date - (due_date_was || 0)
-    elsif start_date.present?
-      start_date - (start_date_was || 0)
-    else
-      0
-    end
-  end
-
   # Users/groups the work_package can be assigned to
   extend Forwardable
   def_delegator :project, :possible_assignees, :assignable_assignees
@@ -666,6 +645,42 @@ class WorkPackage < ActiveRecord::Base
     end
   end
 
+  # Updates start/due dates of following work packages.
+  # If
+  #   * there no start/due dates are set
+  #     => no scheduling will happen.
+  #   * a due date is set and the due date is moved backwards
+  #     => following work package is moved backwards as well
+  #   * a due date is set and the due date is moved forward
+  #     => following work package is moved forward to the point that
+  #        the work package is again scheduled to be after this work package.
+  #        If a delay is defined, that delay is adhered to.
+  #   * only a start date is set and the start date is moved backwards
+  #     => following work package is moved backwards as well
+  #   * only a start date is set and the start date is moved forward
+  #     => following work package is moved forward to the point that
+  #        the work package is again scheduled to be after this work package.
+  #        If a delay is defined, that delay is adhered to.
+  def reschedule_following_work_packages
+    delta = date_rescheduling_delta
+
+    if delta < 0
+      relations_from.each { |r| r.move_target_dates_by(delta) }
+    elsif start_date_changed? || due_date_changed?
+      relations_from.each(&:set_dates_of_target)
+    end
+  end
+
+  def date_rescheduling_delta
+    if due_date.present?
+      due_date - (due_date_was || 0)
+    elsif start_date.present?
+      start_date - (start_date_was || 0)
+    else
+      0
+    end
+  end
+
   def recalculate_attributes_for_former_parent
     recalculate_attributes_for(@former_parent_id) if @former_parent_id
   end