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@@ -1,5 +1,7 @@
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 *Edge*
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+* MySQL: rename_column preserves column defaults.  #466 [Diego Algorta]
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+
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 * Add :from option to calculations.  #397 [Ben Munat]
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 * Add :validate option to associations to enable/disable the automatic validation of associated models. Resolves #301. [Jan De Poorter]

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@@ -450,8 +450,16 @@ module ActiveRecord
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       end
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       def rename_column(table_name, column_name, new_column_name) #:nodoc:
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+        options = {}
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+        if column = columns(table_name).find { |c| c.name == column_name.to_s }
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+          options[:default] = column.default
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+        else
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+          raise ActiveRecordError, "No such column: #{table_name}.#{column_name}"
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+        end
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         current_type = select_one("SHOW COLUMNS FROM #{quote_table_name(table_name)} LIKE '#{column_name}'")["Type"]
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-        execute "ALTER TABLE #{quote_table_name(table_name)} CHANGE #{quote_column_name(column_name)} #{quote_column_name(new_column_name)} #{current_type}"
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+        rename_column_sql = "ALTER TABLE #{quote_table_name(table_name)} CHANGE #{quote_column_name(column_name)} #{quote_column_name(new_column_name)} #{current_type}"
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+        add_column_options!(rename_column_sql, options)
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+        execute(rename_column_sql)
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       end
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       # Maps logical Rails types to MySQL-specific data types.

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@@ -483,6 +483,32 @@ if ActiveRecord::Base.connection.supports_migrations?
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       end
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     end
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+    def test_rename_column_preserves_default_value_not_null
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+      begin
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+        default_before = Developer.connection.columns("developers").find { |c| c.name == "salary" }.default
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+        assert_equal 70000, default_before
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+        Developer.connection.rename_column "developers", "salary", "anual_salary"
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+        Developer.reset_column_information
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+        assert Developer.column_names.include?("anual_salary")
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+        default_after = Developer.connection.columns("developers").find { |c| c.name == "anual_salary" }.default
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+        assert_equal 70000, default_after
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+      ensure
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+        Developer.connection.rename_column "developers", "anual_salary", "salary"
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+        Developer.reset_column_information
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+      end
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+    end
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+
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+    def test_rename_nonexistent_column
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+      ActiveRecord::Base.connection.create_table(:hats) do |table|
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+        table.column :hat_name, :string, :default => nil
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+      end
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+      assert_raises(ActiveRecord::ActiveRecordError) do
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+        Person.connection.rename_column "hats", "nonexistent", "should_fail"
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+      end
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+    ensure
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+      ActiveRecord::Base.connection.drop_table(:hats)
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+    end
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+
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     def test_rename_column_with_sql_reserved_word
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       begin
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         assert_nothing_raised { Person.connection.rename_column "people", "first_name", "group" }