Add active_record.config.validate_migration_timestamps config option.

When set, an `ActiveRecord::InvalidMigrationTimestampError` will be raised if the timestamp
prefix for a migration is more than a day ahead of the timestamp associated with the current time.
This is done to prevent forward-dating of migration files, which can impact migration generation
and other migration commands.

It is turned off by default, but will be turned on for applications starting in Rails 7.2.

activerecord/CHANGELOG.md

@@ -1,3 +1,12 @@
+*   Add `active_record.config.validate_migration_timestamps` option for validating migration timestamps.
+
+    When set, validates that the timestamp prefix for a migration is no more than a day ahead of
+    the timestamp associated with the current time. This is designed to prevent migrations prefixes
+    from being hand-edited to future timestamps, which impacts migration generation and other
+    migration commands.
+
+    *Adrianna Chang*
+
 *   Add support for generated columns in SQLite3 adapter
 
     Generated columns (both stored and dynamic) are supported since version 3.31.0 of SQLite.

activerecord/lib/active_record.rb

@@ -370,6 +370,14 @@ def self.global_executor_concurrency # :nodoc:
   singleton_class.attr_accessor :timestamped_migrations
   self.timestamped_migrations = true
 
+  ##
+  # :singleton-method:
+  # Specify whether or not to validate migration timestamps. When set, an error
+  # will be raised if a timestamp is more than a day ahead of the timestamp
+  # associated with the current time. +timestamped_migrations+ must be set to true.
+  singleton_class.attr_accessor :validate_migration_timestamps
+  self.validate_migration_timestamps = false
+
   ##
   # :singleton-method:
   # Specify strategy to use for executing migrations.

activerecord/lib/active_record/migration.rb

@@ -131,6 +131,22 @@ def initialize(name = nil)
     end
   end
 
+  class InvalidMigrationTimestampError < MigrationError # :nodoc:
+    def initialize(version = nil, name = nil)
+      if version && name
+        super(<<-MSG.squish)
+          Invalid timestamp #{version} for migration file: #{name}.\nTimestamp must be in form YYYYMMDDHHMMSS,
+          and less than #{(Time.now.utc + 1.day).strftime("%Y%m%d%H%M%S")}.
+        MSG
+      else
+        super(<<-MSG.squish)
+          Invalid timestamp for migration.\nTimestamp must be in form YYYYMMDDHHMMSS,
+          and less than #{(Time.now.utc + 1.day).strftime("%Y%m%d%H%M%S")}.
+        MSG
+      end
+    end
+  end
+
   class PendingMigrationError < MigrationError # :nodoc:
     include ActiveSupport::ActionableError
 
@@ -493,7 +509,11 @@ def initialize
   #
   #    20080717013526_your_migration_name.rb
   #
-  # The prefix is a generation timestamp (in UTC).
+  # The prefix is a generation timestamp (in UTC). Timestamps should not be
+  # modified manually. To validate that migration timestamps adhere to the
+  # format Active Record expects, you can use the following configuration option:
+  #
+  #    config.active_record.validate_migration_timestamps = true
   #
   # If you'd prefer to use numeric prefixes, you can turn timestamped migrations
   # off by setting:
@@ -1316,6 +1336,9 @@ def migrations # :nodoc:
       migrations = migration_files.map do |file|
         version, name, scope = parse_migration_filename(file)
         raise IllegalMigrationNameError.new(file) unless version
+        if validate_timestamp? && !valid_migration_timestamp?(version)
+          raise InvalidMigrationTimestampError.new(version, name)
+        end
         version = version.to_i
         name = name.camelize
 
@@ -1331,6 +1354,9 @@ def migrations_status # :nodoc:
       file_list = migration_files.filter_map do |file|
         version, name, scope = parse_migration_filename(file)
         raise IllegalMigrationNameError.new(file) unless version
+        if validate_timestamp? && !valid_migration_timestamp?(version)
+          raise InvalidMigrationTimestampError.new(version, name)
+        end
         version = schema_migration.normalize_migration_number(version)
         status = db_list.delete(version) ? "up" : "down"
         [status, version, (name + scope).humanize]
@@ -1375,6 +1401,14 @@ def parse_migration_filename(filename)
         File.basename(filename).scan(Migration::MigrationFilenameRegexp).first
       end
 
+      def validate_timestamp?
+        ActiveRecord.timestamped_migrations && ActiveRecord.validate_migration_timestamps
+      end
+
+      def valid_migration_timestamp?(version)
+        version.to_i < (Time.now.utc + 1.day).strftime("%Y%m%d%H%M%S").to_i
+      end
+
       def move(direction, steps)
         migrator = Migrator.new(direction, migrations, schema_migration, internal_metadata)
 

activerecord/test/cases/migration_test.rb

@@ -1807,6 +1807,8 @@ def setup
       @verbose_was, ActiveRecord::Migration.verbose = ActiveRecord::Migration.verbose, false
       @schema_migration = ActiveRecord::Base.connection.schema_migration
       @internal_metadata = ActiveRecord::Base.connection.internal_metadata
+      @active_record_validate_timestamps_was = ActiveRecord.validate_migration_timestamps
+      ActiveRecord.validate_migration_timestamps = true
       ActiveRecord::Base.connection.schema_cache.clear!
 
       @migrations_path = MIGRATIONS_ROOT + "/temp"
@@ -1816,15 +1818,69 @@ def setup
     def teardown
       @schema_migration.create_table
       @schema_migration.delete_all_versions
+      ActiveRecord.validate_migration_timestamps = @active_record_validate_timestamps_was
       ActiveRecord::Migration.verbose = @verbose_was
     end
 
+    def test_migration_raises_if_timestamp_greater_than_14_digits
+      with_temp_migration_files(["201801010101010000_test_migration.rb"]) do
+        error = assert_raises(ActiveRecord::InvalidMigrationTimestampError) do
+          @migrator.up(201801010101010000)
+        end
+        assert_match(/Invalid timestamp 201801010101010000 for migration file: test_migration/, error.message)
+      end
+    end
+
+    def test_migration_raises_if_timestamp_is_future_date
+      timestamp = (Time.now.utc + 1.month).strftime("%Y%m%d%H%M%S").to_i
+      with_temp_migration_files(["#{timestamp}_test_migration.rb"]) do
+        error = assert_raises(ActiveRecord::InvalidMigrationTimestampError) do
+          @migrator.up(timestamp)
+        end
+        assert_match(/Invalid timestamp #{timestamp} for migration file: test_migration/, error.message)
+      end
+    end
+
+    def test_migration_succeeds_if_timestamp_is_less_than_one_day_in_the_future
+      timestamp = (Time.now.utc + 1.minute).strftime("%Y%m%d%H%M%S").to_i
+      with_temp_migration_files(["#{timestamp}_test_migration.rb"]) do
+        @migrator.up(timestamp)
+        assert_equal timestamp, @migrator.current_version
+      end
+    end
+
+    def test_migration_succeeds_despite_future_timestamp_if_validate_timestamps_is_false
+      validate_migration_timestamps_was = ActiveRecord.validate_migration_timestamps
+      ActiveRecord.validate_migration_timestamps = false
+
+      timestamp = (Time.now.utc + 1.month).strftime("%Y%m%d%H%M%S").to_i
+      with_temp_migration_files(["#{timestamp}_test_migration.rb"]) do
+        @migrator.up(timestamp)
+        assert_equal timestamp, @migrator.current_version
+      end
+    ensure
+      ActiveRecord.validate_migration_timestamps = validate_migration_timestamps_was
+    end
+
+    def test_migration_succeeds_despite_future_timestamp_if_timestamped_migrations_is_false
+      timestamped_migrations_was = ActiveRecord.timestamped_migrations
+      ActiveRecord.timestamped_migrations = false
+
+      timestamp = (Time.now.utc + 1.month).strftime("%Y%m%d%H%M%S").to_i
+      with_temp_migration_files(["#{timestamp}_test_migration.rb"]) do
+        @migrator.up(timestamp)
+        assert_equal timestamp, @migrator.current_version
+      end
+    ensure
+      ActiveRecord.timestamped_migrations = timestamped_migrations_was
+    end
+
     def test_copied_migrations_at_timestamp_boundary_are_valid
       migrations_path_source = MIGRATIONS_ROOT + "/temp_source"
       migrations_path_dest = MIGRATIONS_ROOT + "/temp_dest"
       migrations = ["20180101010101_test_migration.rb", "20180101010102_test_migration_two.rb", "20180101010103_test_migration_three.rb"]
 
-      with_temp_migration_files(migrations_path_source, migrations) do
+      with_temp_migration_files(migrations, migrations_path_source) do
         travel_to(Time.utc(2023, 12, 1, 10, 10, 59)) do
           ActiveRecord::Migration.copy(migrations_path_dest, temp: migrations_path_source)
 
@@ -1847,7 +1903,7 @@ def test_copied_migrations_at_timestamp_boundary_are_valid
     end
 
     private
-      def with_temp_migration_files(migrations_dir, filenames)
+      def with_temp_migration_files(filenames, migrations_dir = @migrations_path)
         Dir.mkdir(migrations_dir) unless Dir.exist?(migrations_dir)
 
         paths = []

guides/source/configuring.md

@@ -58,6 +58,10 @@ NOTE: If you need to apply configuration directly to a class, use a [lazy load h
 
 Below are the default values associated with each target version. In cases of conflicting values, newer versions take precedence over older versions.
 
+#### Default Values for Target Version 7.2
+
+- [`config.active_record.validate_migration_timestamps`](#config-active-record-validate-migration-timestamps): `true`
+
 #### Default Values for Target Version 7.1
 
 - [`config.action_dispatch.debug_exception_log_level`](#config-action-dispatch-debug-exception-log-level): `:error`
@@ -1047,6 +1051,20 @@ Specifies if an error should be raised if the order of a query is ignored during
 
 Controls whether migrations are numbered with serial integers or with timestamps. The default is `true`, to use timestamps, which are preferred if there are multiple developers working on the same application.
 
+#### `config.active_record.validate_migration_timestamps`
+
+Controls whether to validate migration timestamps. When set, an error will be raised if the
+timestamp prefix for a migration is more than a day ahead of the timestamp associated with the
+current time. This is done to prevent forward-dating of migration files, which can impact migration
+generation and other migration commands. `config.active_record.timestamped_migrations` must be set to `true`.
+
+The default value depends on the `config.load_defaults` target version:
+
+| Starting with version | The default value is |
+| --------------------- | -------------------- |
+| (original)            | `false`              |
+| 7.2                   | `true`               |
+
 #### `config.active_record.db_warnings_action`
 
 Controls the action to be taken when a SQL query produces a warning. The following options are available:

railties/lib/rails/application/configuration.rb

@@ -323,6 +323,10 @@ def load_defaults(target_version)
           end
         when "7.2"
           load_defaults "7.1"
+
+          if respond_to?(:active_record)
+            active_record.validate_migration_timestamps = true
+          end
         else
           raise "Unknown version #{target_version.to_s.inspect}"
         end

railties/lib/rails/generators/rails/app/templates/config/initializers/new_framework_defaults_7_2.rb.tt

@@ -8,3 +8,14 @@
 #
 # Read the Guide for Upgrading Ruby on Rails for more info on each option.
 # https://guides.rubyonrails.org/upgrading_ruby_on_rails.html
+
+###
+# Enable validation of migration timestamps. When set, an ActiveRecord::InvalidMigrationTimestampError
+# will be raised if the timestamp prefix for a migration is more than a day ahead of the timestamp
+# associated with the current time. This is done to prevent forward-dating of migration files, which can
+# impact migration generation and other migration commands.
+#
+# Applications with existing timestamped migrations that do not adhere to the
+# expected format can disable validation by setting this config to `false`.
+#++
+# Rails.application.config.active_record.validate_migration_timestamps = true

railties/test/application/loading_test.rb

@@ -319,6 +319,7 @@ class User
   test "columns migrations also trigger reloading" do
     add_to_config <<-RUBY
       config.enable_reloading = true
+      config.active_record.timestamped_migrations = false
     RUBY
 
     app_file "config/routes.rb", <<-RUBY

railties/test/application/rake/migrations_test.rb

@@ -8,6 +8,7 @@ class RakeMigrationsTest < ActiveSupport::TestCase
       def setup
         build_app
         FileUtils.rm_rf("#{app_path}/config/environments")
+        add_to_config("config.active_record.timestamped_migrations = false")
       end
 
       def teardown
@@ -17,7 +18,7 @@ def teardown
       test "running migrations with given scope" do
         rails "generate", "model", "user", "username:string", "password:string"
 
-        app_file "db/migrate/01_a_migration.bukkits.rb", <<-MIGRATION
+        app_file "db/migrate/02_a_migration.bukkits.rb", <<-MIGRATION
           class AMigration < ActiveRecord::Migration::Current
           end
         MIGRATION
@@ -200,6 +201,8 @@ class TwoMigration < ActiveRecord::Migration::Current
       end
 
       test "migration status" do
+        remove_from_config("config.active_record.timestamped_migrations = false")
+
         rails "generate", "model", "user", "username:string", "password:string"
         rails "generate", "migration", "add_email_to_users", "email:string"
         rails "db:migrate"
@@ -217,7 +220,7 @@ class TwoMigration < ActiveRecord::Migration::Current
       end
 
       test "migration status without timestamps" do
-        add_to_config("config.active_record.timestamped_migrations = false")
+        remove_from_config("config.active_record.timestamped_migrations = false")
 
         rails "generate", "model", "user", "username:string", "password:string"
         rails "generate", "migration", "add_email_to_users", "email:string"
@@ -236,6 +239,8 @@ class TwoMigration < ActiveRecord::Migration::Current
       end
 
       test "migration status after rollback and redo" do
+        remove_from_config("config.active_record.timestamped_migrations = false")
+
         rails "generate", "model", "user", "username:string", "password:string"
         rails "generate", "migration", "add_email_to_users", "email:string"
         rails "db:migrate"
@@ -259,6 +264,8 @@ class TwoMigration < ActiveRecord::Migration::Current
       end
 
       test "migration status after rollback and forward" do
+        remove_from_config("config.active_record.timestamped_migrations = false")
+
         rails "generate", "model", "user", "username:string", "password:string"
         rails "generate", "migration", "add_email_to_users", "email:string"
         rails "db:migrate"
@@ -283,6 +290,8 @@ class TwoMigration < ActiveRecord::Migration::Current
 
       test "raise error on any move when current migration does not exist" do
         Dir.chdir(app_path) do
+          remove_from_config("config.active_record.timestamped_migrations = false")
+
           rails "generate", "model", "user", "username:string", "password:string"
           rails "generate", "migration", "add_email_to_users", "email:string"
           rails "db:migrate"
@@ -382,8 +391,6 @@ class TwoMigration < ActiveRecord::Migration::Current
       end
 
       test "migration status after rollback and redo without timestamps" do
-        add_to_config("config.active_record.timestamped_migrations = false")
-
         rails "generate", "model", "user", "username:string", "password:string"
         rails "generate", "migration", "add_email_to_users", "email:string"
         rails "db:migrate"
@@ -497,6 +504,8 @@ class TwoMigration < ActiveRecord::Migration::Current
 
       test "migration status migrated file is deleted" do
         Dir.chdir(app_path) do
+          remove_from_config("config.active_record.timestamped_migrations = false")
+
           rails "generate", "model", "user", "username:string", "password:string"
           rails "generate", "migration", "add_email_to_users", "email:string"
           rails "db:migrate"
@@ -523,7 +532,7 @@ class ApplicationRecord < ActiveRecord::Base
 
           rails("db:migrate")
 
-          app_file "db/migrate/01_a_migration.bukkits.rb", <<-MIGRATION
+          app_file "db/migrate/02_a_migration.bukkits.rb", <<-MIGRATION
             class AMigration < ActiveRecord::Migration::Current
               def change
                 User.first

railties/test/application/rake/multi_dbs_test.rb

@@ -10,6 +10,7 @@ class RakeMultiDbsTest < ActiveSupport::TestCase
       def setup
         build_app(multi_db: true)
         FileUtils.rm_rf("#{app_path}/config/environments")
+        add_to_config("config.active_record.timestamped_migrations = false")
       end
 
       def teardown
@@ -779,11 +780,13 @@ class TwoMigration < ActiveRecord::Migration::Current
       end
 
       test "db:migrate:status works on all databases" do
+        remove_from_config("config.active_record.timestamped_migrations = false")
         require "#{app_path}/config/environment"
         db_migrate_and_migrate_status
       end
 
       test "db:migrate:status:namespace works" do
+        remove_from_config("config.active_record.timestamped_migrations = false")
         require "#{app_path}/config/environment"
         ActiveRecord::Base.configurations.configs_for(env_name: Rails.env).each do |db_config|
           db_migrate_namespaced db_config.name