Migrations: raise if a column is duplicated. Closes #7345.

git-svn-id: http://svn-commit.rubyonrails.org/rails/trunk@6961 5ecf4fe2-1ee6-0310-87b1-e25e094e27de

activerecord/CHANGELOG

@@ -1,5 +1,7 @@
 *SVN*
 
+* Migrations: raise if a column is duplicated.  #7345 [Jeremy McAnally, Josh Peek]
+
 * Fixtures: correctly delete and insert fixtures in a single transaction.  #8553 [Michael Schuerig]
 
 * Fixtures: people(:technomancy, :josh) returns both fixtures.  #7880 [technomancy, Josh Peek]

activerecord/lib/active_record/connection_adapters/abstract/schema_definitions.rb

@@ -351,7 +351,8 @@ module ActiveRecord
       # There's a short-hand method for each of the type values declared at the top. And then there's 
       # TableDefinition#timestamps that'll add created_at and updated_at as datetimes.
       def column(name, type, options = {})
-        column = self[name] || ColumnDefinition.new(@base, name, type)
+        raise "You already defined column '#{name}'." if self[name]
+        column = ColumnDefinition.new(@base, name, type)
         column.limit = options[:limit] || native[type.to_sym][:limit] if options[:limit] or native[type.to_sym]
         column.precision = options[:precision]
         column.scale = options[:scale]

activerecord/test/migration_test.rb

@@ -807,6 +807,22 @@ if ActiveRecord::Base.connection.supports_migrations?
       end
     end
 
+    def test_should_disallow_duplicate_column_definition
+      assert_raises(ActiveRecord::StatementInvalid) do
+        Person.connection.add_column("people", "full_name", :string, :limit => 40)
+        Person.connection.add_column("people", "full_name", :text)
+      end
+
+      assert_raises(RuntimeError) do
+        Person.connection.create_table :people_with_errors do |t|
+          t.column "full_name", :string, :limit => 40
+          t.column "full_name", :text
+        end
+      end
+
+      Person.reset_column_information
+    end
+
   end
 end