Handle change_column error when column has default binding or indexes.

Tests for #455.

Author: Etienne Massip

lib/arjdbc/mssql/adapter.rb

@@ -363,9 +363,24 @@ def rename_column(table_name, column_name, new_column_name)
 
     # @override
     def change_column(table_name, column_name, type, options = {})
+
+      indexes = []
+      column_object = columns(table_name).detect { |c| c.name.to_s == column_name.to_s }
+
+      if options_include_default?(options) || (column_object && column_object.type != type.to_sym)
+        remove_default_constraint(table_name, column_name)
+        indexes = indexes(table_name).select{ |index| index.columns.include?(column_name.to_s) }
+        remove_indexes(table_name, column_name)
+      end
+
       clear_cached_table(table_name)
       change_column_type(table_name, column_name, type, options)
       change_column_default(table_name, column_name, options[:default]) if options_include_default?(options)
+
+      #Add any removed indexes back
+      indexes.each do |index|
+        execute "CREATE INDEX #{quote_table_name(index.name)} ON #{quote_table_name(table_name)} (#{index.columns.collect {|c|quote_column_name(c)}.join(', ')})"
+      end
     end
 
     def change_column_type(table_name, column_name, type, options = {})

test/models/entry.rb

@@ -3,6 +3,7 @@ def self.up
     create_table "entries", :force => true do |t|
       t.column :title, :string, :limit => 100
       t.column :content, :text
+      t.column :status, :string, :default => 'unknown'
       t.column :rating, :decimal, :precision => 10, :scale => 2
       t.column :user_id, :integer
       t.column :updated_on, :datetime # treated as date "_on" convention

test/simple.rb

@@ -618,6 +618,36 @@ def test_add_null_column_with_no_default
     end
   end
 
+  def test_change_column_whithout_default_option_should_drop_existing_default
+
+    Entry.reset_column_information
+    status_column = Entry.columns.find { |c| c.name == 'status' }
+    assert_equal :string, status_column.type
+    assert_equal 'unknown', status_column.default
+
+    Entry.connection.change_column :entries, :status, :text
+
+    Entry.reset_column_information
+    status_column = Entry.columns.find { |c| c.name == 'status' }
+    assert_equal :text, status_column.type
+    assert !status_column.default
+  end
+
+  def test_change_column_whith_default_option_should_set_new_default
+
+    Entry.reset_column_information
+    status_column = Entry.columns.find { |c| c.name == 'status' }
+    assert_equal :string, status_column.type
+    assert_equal 'unknown', status_column.default
+
+    Entry.connection.change_column :entries, :status, :text, :default => 'new'
+
+    Entry.reset_column_information
+    status_column = Entry.columns.find { |c| c.name == 'status' }
+    assert_equal :text, status_column.type
+    assert_equal 'new', status_column.default
+  end
+ 
   def test_add_null_column_with_nil_default
     # You must specify a default value with most databases
     if ActiveRecord::Base.connection.adapter_name =~ /mysql/i
@@ -1164,6 +1194,7 @@ def test_select_rows
       when 'id' then assert_not_nil row[i]
       when 'title' then assert_equal 'title 1', row[i]
       when 'content' then assert_equal 'content 1', row[i]
+      when 'status' then assert_equal 'unknown', row[i]
       when 'user_id'
         if defined? JRUBY_VERSION
           assert_equal user.id, row[i]
@@ -1182,6 +1213,7 @@ def test_select_rows
       when 'id' then assert_not_nil row[i]
       when 'title' then assert_equal 'title 2', row[i]
       when 'content' then assert_equal 'content 2', row[i]
+      when 'status' then assert_equal 'unknown', row[i]
       when 'user_id'
         if defined? JRUBY_VERSION
           assert_equal user.id, row[i]