Controller (app/controllers/admin/deduplicate_patients_controller.rb):

 - Added filter_enabled? method that checks Flipper.enabled?(:patient_deduplication_filter, current_admin)
 - before_action :set_filter_options now only runs if filter is enabled
 - Filter logic in show action is conditional on feature flag

Author: sshinde-rtsl

app/controllers/admin/deduplicate_patients_controller.rb

@@ -1,23 +1,26 @@
 class Admin::DeduplicatePatientsController < AdminController
   skip_before_action :verify_authenticity_token
-  before_action :set_filter_options, only: [:show]
+  before_action :set_filter_options, only: [:show], if: :filter_enabled?
   DUPLICATE_LIMIT = 250
 
   def show
     facilities = current_admin.accessible_facilities(:manage)
     authorize { facilities.any? }
 
-    # Apply facility filter if selected
-    filtered_facilities = if @selected_facility.present?
+    # Apply facility filter if selected and feature flag is enabled
+    filtered_facilities = if filter_enabled? && @selected_facility.present?
       facilities.where(id: @selected_facility.id)
-    elsif @selected_district.present?
+    elsif filter_enabled? && @selected_district.present?
       facilities.where(id: @selected_district.facilities)
     else
       facilities
     end
 
     # Scoping by facilities is costly for users who have a lot of facilities
-    duplicate_patient_ids = if current_admin.accessible_organizations(:manage).any? && !@selected_district.present? && !@selected_facility.present?
+    use_all_organizations = current_admin.accessible_organizations(:manage).any? &&
+      (!filter_enabled? || (!@selected_district.present? && !@selected_facility.present?))
+
+    duplicate_patient_ids = if use_all_organizations
       PatientDeduplication::Strategies.identifier_excluding_full_name_match(limit: DUPLICATE_LIMIT)
     else
       PatientDeduplication::Strategies.identifier_excluding_full_name_match_for_facilities(
@@ -88,4 +91,8 @@ def populate_facilities
   def set_selected_facility
     @selected_facility = @facilities.find_by(id: params[:facility_id]) if params[:facility_id].present?
   end
+
+  def filter_enabled?
+    Flipper.enabled?(:patient_deduplication_filter, current_admin)
+  end
 end

app/views/admin/deduplicate_patients/show.html.erb

@@ -1,34 +1,36 @@
 <h1 class="page-title mb-3">Merge duplicate patients</h1>
 
-<%= bootstrap_form_with(url: admin_deduplication_path, method: :get, layout: :horizontal, class: "mb-4") do |form| %>
-  <% html_select_options = { onchange: "this.form.submit();" }
-     searchable_select_options = html_select_options.merge(class: "selectpicker", data: {live_search: true}) %>
-  <div class="form-row">
-    <div id="district-selector" class="form-group col-md-4">
-      <%= form.select :district_slug,
-                      @districts.order(:name).map { |district| [district.name, district.slug] },
-                      {
-                        hide_label: true,
-                        selected: @selected_district&.slug,
-                        wrapper: false
-                      },
-                      searchable_select_options
-      %>
-    </div>
-    <div id="facility-selector" class="form-group col-md-4">
-      <%= form.select :facility_id,
-                      @facilities.order(:name).map { |facility| [facility.label_with_district, facility.id] },
-                      {
+<% if Flipper.enabled?(:patient_deduplication_filter, current_admin) %>
+  <%= bootstrap_form_with(url: admin_deduplication_path, method: :get, layout: :horizontal, class: "mb-4") do |form| %>
+    <% html_select_options = { onchange: "this.form.submit();" }
+       searchable_select_options = html_select_options.merge(class: "selectpicker", data: {live_search: true}) %>
+    <div class="form-row">
+      <div id="district-selector" class="form-group col-md-4">
+        <%= form.select :district_slug,
+                        @districts.order(:name).map { |district| [district.name, district.slug] },
+                        {
                           hide_label: true,
-                          include_blank: "All facilities",
-                          selected: @selected_facility&.id,
+                          selected: @selected_district&.slug,
                           wrapper: false
-                      },
-                      searchable_select_options
-      %>
+                        },
+                        searchable_select_options
+        %>
+      </div>
+      <div id="facility-selector" class="form-group col-md-4">
+        <%= form.select :facility_id,
+                        @facilities.order(:name).map { |facility| [facility.label_with_district, facility.id] },
+                        {
+                            hide_label: true,
+                            include_blank: "All facilities",
+                            selected: @selected_facility&.id,
+                            wrapper: false
+                        },
+                        searchable_select_options
+        %>
+      </div>
     </div>
-  </div>
-  <%= form.submit "Filter", style: "display: none" %>
+    <%= form.submit "Filter", style: "display: none" %>
+  <% end %>
 <% end %>
 
 <div class="card">