Add allow_missing_migration_files option

This PR allow use allow_missing_migration_files in config

ref to sequel commit jeremyevans/sequel@b64b812

README.md

@@ -166,6 +166,9 @@ You can configure some options with the usual rails mechanism, in
     # Allowed options: :sql, :ruby.
     config.sequel.schema_format = :sql
 
+    # Allowed options: true, false, default false
+    config.sequel.allow_missing_migration_files = true
+
     # Whether to dump the schema after successful migrations.
     # Defaults to false in production and test, true otherwise.
     config.sequel.schema_dump = true

lib/sequel_rails/migrations.rb

@@ -6,6 +6,7 @@ class << self
       def migrate(version = nil)
         opts = {}
         opts[:target] = version.to_i if version
+        opts[:allow_missing_migration_files] = !!SequelRails.configuration.allow_missing_migration_files
 
         if migrations_dir.directory?
           ::Sequel::Migrator.run(::Sequel::Model.db, migrations_dir, opts)
@@ -43,8 +44,6 @@ def migrations_dir
       def current_migration
         return unless available_migrations?
 
-        migrator_class = ::Sequel::Migrator.send(:migrator_class, migrations_dir)
-        migrator = migrator_class.new ::Sequel::Model.db, migrations_dir
         if migrator.respond_to?(:applied_migrations)
           migrator.applied_migrations.last
         elsif migrator.respond_to?(:current_version)
@@ -55,8 +54,6 @@ def current_migration
       def previous_migration
         return unless available_migrations?
 
-        migrator_class = ::Sequel::Migrator.send(:migrator_class, migrations_dir)
-        migrator = migrator_class.new ::Sequel::Model.db, migrations_dir
         if migrator.respond_to?(:applied_migrations)
           migrator.applied_migrations[-2] || '0'
         elsif migrator.respond_to?(:current_version)
@@ -67,6 +64,18 @@ def previous_migration
       def available_migrations?
         File.exist?(migrations_dir) && Dir[File.join(migrations_dir, '*')].any?
       end
+
+      def migrator
+        return @migrator if defined?(@migrator)
+
+        migrator_class = ::Sequel::Migrator.send(:migrator_class, migrations_dir)
+
+        @migrator = migrator_class.new(
+          ::Sequel::Model.db,
+          migrations_dir,
+          allow_missing_migration_files: !!SequelRails.configuration.allow_missing_migration_files
+        )
+      end
     end
   end
 end

spec/lib/sequel_rails/migrations_spec.rb

@@ -8,23 +8,40 @@
     describe ".#{migration_method}" do
       let(:result) { double(:result) }
       context 'with no version specified' do
-        let(:opts) { {} }
         it 'runs migrations using Sequel::Migrator' do
           expect(::Sequel::Migrator).to receive(:run).with(
-            db, Rails.root.join('db/migrate'), opts
+            db, Rails.root.join('db/migrate'), allow_missing_migration_files: false
           ).and_return result
           expect(described_class.send(migration_method)).to be(result)
         end
       end
       context 'with version specified' do
-        let(:opts) { { :target => 1 } }
         it 'runs migrations using Sequel::Migrator' do
           expect(::Sequel::Migrator).to receive(:run).with(
-            db, Rails.root.join('db/migrate'), opts
+            db, Rails.root.join('db/migrate'), allow_missing_migration_files: false, target: 1
           ).and_return result
           expect(described_class.send(migration_method, 1)).to be(result)
         end
       end
+
+      context 'with allow_missing_migration_files' do
+        around do |ex|
+          option = SequelRails.configuration.allow_missing_migration_files
+          SequelRails.configuration.allow_missing_migration_files = true
+
+          ex.run
+
+          SequelRails.configuration.allow_missing_migration_files = option
+        end
+
+        it 'runs migrations using Sequel::Migrator' do
+          expect(::Sequel::Migrator).to receive(:run).with(
+            db, Rails.root.join('db/migrate'), allow_missing_migration_files: true
+          ).and_return result
+
+          described_class.send(migration_method)
+        end
+      end
     end
   end