Provide feedback when a user tries to double-reshare

app/controllers/reshares_controller.rb

@@ -4,7 +4,7 @@ class ResharesController < ApplicationController
 
   def create
     @reshare = current_user.build_post(:reshare, :root_guid => params[:root_guid])
-    if @reshare.save!
+    if @reshare.save
       current_user.add_to_streams(@reshare, current_user.aspects)
       current_user.dispatch_post(@reshare, :url => post_url(@reshare), :additional_subscribers => @reshare.root.author)
     end

app/helpers/reshares_helper.rb

 module ResharesHelper
+  def reshare_error_message(reshare)
+    if @reshare.errors[:root_guid].present?
+      escape_javascript(@reshare.errors[:root_guid].first)
+    else
+      escape_javascript(t('reshares.create.failure'))
+    end
+  end
 end

app/views/reshares/create.js.erb

-$('.stream_element#<%=params[:root_guid]%>').addClass('reshared');
-ContentUpdater.addPostToStream(
-    "<%= escape_javascript(render(:partial => 'shared/stream_element', :locals => {:post => @reshare }))=%>"
-);
+<% if @reshare.persisted? %>
+  $('.stream_element#<%=params[:root_guid]%>').addClass('reshared');
+  ContentUpdater.addPostToStream(
+      "<%= escape_javascript(render(:partial => 'shared/stream_element', :locals => {:post => @reshare }))=%>"
+  );
+  <% else  %>
+  Diaspora.widgets.flashes.render({success:false,
+    notice: "<%= reshare_error_message(@reshare)  %>"});
+<% end %>

config/locales/diaspora/en-US.yml

@@ -26,3 +26,4 @@
                   attributes:
                       from_id:
                           taken: "is a duplicate of a pre-existing request."
+

config/locales/diaspora/en.yml

@@ -65,8 +65,10 @@ en:
           attributes:
             from_id:
               taken: "is a duplicate of a pre-existing request."
-
-
+        reshare:
+          attributes:
+            root_guid:
+              taken: "You've already reshared that post!"
   error_messages:
     helper:
       invalid_fields: "Invalid Fields"
@@ -579,7 +581,9 @@ en:
         few: "%{count} new requests!"
         many: "%{count} new requests!"
         other: "%{count} new requests!"
-
+  reshares:
+    create:
+      failure: "There was an error resharing this post."
   services:
     index:
       logged_in_as: "logged in as"

config/locales/javascript/javascript.en.yml

@@ -47,3 +47,5 @@ en:
       comments:
         show: "show all comments"
         hide: "hide comments"
+      reshares:
+        duplicate:"You've already reshared that post!"