Yield user-friendly error message when import fail

Author: ifyouseewendy

lib/active_admin_import/dsl.rb

@@ -35,7 +35,7 @@ module DSL
           flash[:notice] = I18n.t('active_admin_import.imported', count: result.imported_qty, model: model_name, plural_model: plural_model_name)
         end
         if result.has_failed?
-          flash[:error] = I18n.t('active_admin_import.failed', count: result.failed.count, model: model_name, plural_model: plural_model_name)
+          flash[:error] = I18n.t('active_admin_import.failed', count: result.failed.count, model: model_name, plural_model: plural_model_name, message: result.failed_message)
         end
       end
     end

lib/active_admin_import/import_result.rb

@@ -8,18 +8,18 @@ def initialize
     end
 
     def add(result, qty)
-       @failed += result.failed_instances
-       @total+=qty
+      @failed += result.failed_instances
+      @total  += qty
     end
-        
+
     def imported_qty
       total - failed.count
-    end 
-    
+    end
+
     def has_imported?
       imported_qty > 0
     end
-    
+
     def has_failed?
       @failed.any?
     end
@@ -28,5 +28,11 @@ def empty?
       total == 0
     end
 
+    def failed_message
+      failed.map{|record|
+        errors = record.errors
+        (errors.full_messages.zip errors.keys.map{|k| record.send k}).map{|ms| ms.join(' - ')}.join(', ')
+      }.join(" ; ")
+    end
   end
-end
+end