Merge pull request #3603 from consul/admin_stats_before_voting_phase

Avoid error when accessing final voting stats before the balloting phase

app/controllers/admin/stats_controller.rb

@@ -74,6 +74,9 @@ class Admin::StatsController < Admin::BaseController
 
   def budget_balloting
     @budget = Budget.find(params[:budget_id])
+
+    authorize! :read_admin_stats, @budget, message: t("admin.stats.budgets.no_data_before_balloting_phase")
+
     @user_count = @budget.ballots.select {|ballot| ballot.lines.any? }.count
 
     @vote_count = @budget.lines.count

app/models/abilities/administrator.rb

@@ -66,6 +66,8 @@ module Abilities
       can [:valuate, :comment_valuation], Budget::Investment
       can :create, Budget::ValuatorAssignment
 
+      can(:read_admin_stats, Budget) { |budget| budget.balloting_or_later? }
+
       can [:search, :edit, :update, :create, :index, :destroy], Banner
 
       can [:index, :create, :edit, :update, :destroy], Geozone

app/views/admin/stats/budgets.html.erb

@@ -9,8 +9,15 @@
         <strong><%= budget.name %></strong>
       </td>
       <td>
-        <%= link_to t("admin.stats.budgets.supporting_phase"), budget_supporting_admin_stats_path(budget_id: budget.id), class: "button hollow" %>
-        <%= link_to t("admin.stats.budgets.balloting_phase"), budget_balloting_admin_stats_path(budget_id: budget.id), class: "button hollow" %>
+        <%= link_to t("admin.stats.budgets.supporting_phase"),
+                    budget_supporting_admin_stats_path(budget_id: budget.id),
+                    class: "button hollow" %>
+
+        <% if can? :read_admin_stats, budget %>
+          <%= link_to t("admin.stats.budgets.balloting_phase"),
+                      budget_balloting_admin_stats_path(budget_id: budget.id),
+                      class: "button hollow" %>
+        <% end %>
       </td>
     </tr>
   </table>