Remove existing migration when using 'rails generate model' with --force [#5526 state:committed]

Signed-off-by: José Valim <jose.valim@gmail.com>

railties/lib/rails/generators/migration.rb

@@ -53,7 +53,11 @@ module Rails
         destination = self.class.migration_exists?(migration_dir, @migration_file_name)
 
         if behavior == :invoke
-          raise Error, "Another migration is already named #{@migration_file_name}: #{destination}" if destination
+          if destination && options.force?
+            remove_file(destination)
+          elsif destination
+            raise Error, "Another migration is already named #{@migration_file_name}: #{destination}"
+          end
           destination = File.join(migration_dir, "#{@migration_number}_#{@migration_file_name}.rb")
         end
 

railties/test/generators/model_generator_test.rb

@@ -165,6 +165,15 @@ class ModelGeneratorTest < Rails::Generators::TestCase
     assert_no_migration "db/migrate/create_accounts.rb"
   end
 
+  def test_existing_migration_is_removed_on_force
+    run_generator
+    old_migration = Dir["#{destination_root}/db/migrate/*_create_accounts.rb"].first
+    error = capture(:stderr) { run_generator ["Account", "--force"] }
+    assert_no_match /Another migration is already named create_foos/, error
+    assert_no_file old_migration
+    assert_migration 'db/migrate/create_accounts.rb'
+  end
+
   def test_invokes_default_test_framework
     run_generator
     assert_file "test/unit/account_test.rb", /class AccountTest < ActiveSupport::TestCase/