Merge pull request #6665 from schneems/schneems/raise-migration-error

Notify A User they Have Pending Migrations

activerecord/lib/active_record/migration.rb

@@ -32,6 +32,12 @@ module ActiveRecord
     end
   end
 
+  class PendingMigrationError < ActiveRecordError#:nodoc:
+    def initialize
+      super("Migrations are pending run 'bundle exec rake db:migrate RAILS_ENV=#{ENV['RAILS_ENV']}' to resolve the issue")
+    end
+  end
+
   # = Active Record Migrations
   #
   # Migrations can manage the evolution of a schema used by several physical
@@ -326,10 +332,28 @@ module ActiveRecord
   class Migration
     autoload :CommandRecorder, 'active_record/migration/command_recorder'
 
+
+    # This class is used to verify that all migrations have been run before
+    # loading a web page if config.active_record.migration_error is set to :page_load
+    class CheckPending
+      def initialize(app)
+        @app = app
+      end
+
+      def call(env)
+        ActiveRecord::Migration.check_pending!
+        status, headers, body = @app.call(env)
+      end
+    end
+
     class << self
       attr_accessor :delegate # :nodoc:
     end
 
+    def self.check_pending!
+      raise ActiveRecord::PendingMigrationError if ActiveRecord::Migrator::needs_migrations?
+    end
+
     def self.method_missing(name, *args, &block) # :nodoc:
       (delegate || superclass.delegate).send(name, *args, &block)
     end
@@ -605,6 +629,14 @@ module ActiveRecord
         end
       end
 
+      def needs_migrations?
+        current_version < last_version
+      end
+
+      def last_version
+        migrations(migrations_paths).last.try(:version)||0
+      end
+
       def proper_table_name(name)
         # Use the Active Record objects own table_name, or pre/suffix from ActiveRecord::Base if name is a symbol/string
         name.table_name rescue "#{ActiveRecord::Base.table_name_prefix}#{name}#{ActiveRecord::Base.table_name_suffix}"

activerecord/lib/active_record/railtie.rb

@@ -59,6 +59,13 @@ module ActiveRecord
       ActiveSupport.on_load(:active_record) { self.logger ||= ::Rails.logger }
     end
 
+    initializer "active_record.migration_error" do |app|
+      if config.active_record.delete(:migration_error) == :page_load
+        config.app_middleware.insert_after "::ActionDispatch::Callbacks",
+          "ActiveRecord::Migration::CheckPending"
+      end
+    end
+
     initializer "active_record.set_configs" do |app|
       ActiveSupport.on_load(:active_record) do
         if app.config.active_record.delete(:whitelist_attributes)

activerecord/test/cases/migration_test.rb

@@ -56,6 +56,21 @@ class MigrationTest < ActiveRecord::TestCase
     Person.reset_column_information
   end
 
+  def test_migrator_versions
+    migrations_path = MIGRATIONS_ROOT + "/valid"
+    ActiveRecord::Migrator.migrations_paths = migrations_path
+
+    ActiveRecord::Migrator.up(migrations_path)
+    assert_equal 3, ActiveRecord::Migrator.current_version
+    assert_equal 3, ActiveRecord::Migrator.last_version
+    assert_equal false, ActiveRecord::Migrator.needs_migrations?
+
+    ActiveRecord::Migrator.down(MIGRATIONS_ROOT + "/valid")
+    assert_equal 0, ActiveRecord::Migrator.current_version
+    assert_equal 3, ActiveRecord::Migrator.last_version
+    assert_equal true, ActiveRecord::Migrator.needs_migrations?
+  end
+
   def test_create_table_with_force_true_does_not_drop_nonexisting_table
     if Person.connection.table_exists?(:testings2)
       Person.connection.drop_table :testings2

railties/lib/rails/generators/rails/app/templates/config/environments/development.rb.tt

@@ -26,6 +26,9 @@
   # Log the query plan for queries taking more than this (works
   # with SQLite, MySQL, and PostgreSQL).
   config.active_record.auto_explain_threshold_in_seconds = 0.5
+
+  # Raise an error on page load if there are pending migrations
+  config.active_record.migration_error = :page_load
   <%- end -%>
 
   <%- unless options.skip_sprockets? -%>

railties/lib/rails/generators/rails/app/templates/test/test_helper.rb

@@ -4,6 +4,8 @@ require 'rails/test_help'
 
 class ActiveSupport::TestCase
 <% unless  options[:skip_active_record] -%>
+  ActiveRecord::Migration.check_pending!
+
   # Setup all fixtures in test/fixtures/*.(yml|csv) for all tests in alphabetical order.
   #
   # Note: You'll currently still have to declare fixtures explicitly in integration tests

railties/test/application/configuration_test.rb

@@ -41,6 +41,21 @@ module ApplicationTests
       FileUtils.rm_rf(new_app) if File.directory?(new_app)
     end
 
+    test "a renders exception on pending migration" do
+      add_to_config <<-RUBY
+        config.active_record.migration_error    = :page_load
+        config.consider_all_requests_local      = true
+        config.action_dispatch.show_exceptions  = true
+      RUBY
+
+      require "#{app_path}/config/environment"
+      ActiveRecord::Migrator.stubs(:needs_migrations?).returns(true)
+
+      get "/foo"
+      assert_equal 500, last_response.status
+      assert_match "ActiveRecord::PendingMigrationError", last_response.body
+    end
+
     test "multiple queue construction is possible" do
       require 'rails'
       require "#{app_path}/config/environment"