Fix `bin/rails db:migrate` with specified `VERSION`

Ensure that `bin/rails db:migrate` with specified `VERSION` reverts
all migrations only if `VERSION` is `0`.
Raise error if target migration doesn't exist.

3 files changed, 28 insertions, 8 deletions

diff --git a/activerecord/lib/active_record/migration.rb b/activerecord/lib/active_record/migration.rb
index 1485687053..d12a979a7f 100644
--- a/activerecord/lib/active_record/migration.rb
+++ b/activerecord/lib/active_record/migration.rb
@@ -1224,7 +1224,7 @@ module ActiveRecord
 
       # Return true if a valid version is not provided.
       def invalid_target?
-        !target && @target_version && @target_version > 0
+        @target_version && @target_version != 0 && !target
       end
 
       def execute_migration_in_transaction(migration, direction)
diff --git a/activerecord/lib/active_record/railties/databases.rake b/activerecord/lib/active_record/railties/databases.rake
index 723272b4b2..3bca2982e0 100644
--- a/activerecord/lib/active_record/railties/databases.rake
+++ b/activerecord/lib/active_record/railties/databases.rake
@@ -97,16 +97,27 @@ db_namespace = namespace :db do
     task up: [:environment, :load_config] do
       raise "VERSION is required" if !ENV["VERSION"] || ENV["VERSION"].empty?
 
-      version = ENV["VERSION"] ? ENV["VERSION"].to_i : nil
-      ActiveRecord::Migrator.run(:up, ActiveRecord::Tasks::DatabaseTasks.migrations_paths, version)
+      ActiveRecord::Tasks::DatabaseTasks.check_target_version
+
+      ActiveRecord::Migrator.run(
+        :up,
+        ActiveRecord::Tasks::DatabaseTasks.migrations_paths,
+        ActiveRecord::Tasks::DatabaseTasks.target_version
+      )
       db_namespace["_dump"].invoke
     end
 
     # desc 'Runs the "down" for a given migration VERSION.'
     task down: [:environment, :load_config] do
       raise "VERSION is required - To go down one migration, use db:rollback" if !ENV["VERSION"] || ENV["VERSION"].empty?
-      version = ENV["VERSION"] ? ENV["VERSION"].to_i : nil
-      ActiveRecord::Migrator.run(:down, ActiveRecord::Tasks::DatabaseTasks.migrations_paths, version)
+
+      ActiveRecord::Tasks::DatabaseTasks.check_target_version
+
+      ActiveRecord::Migrator.run(
+        :down,
+        ActiveRecord::Tasks::DatabaseTasks.migrations_paths,
+        ActiveRecord::Tasks::DatabaseTasks.target_version
+      )
       db_namespace["_dump"].invoke
     end
 
diff --git a/activerecord/lib/active_record/tasks/database_tasks.rb b/activerecord/lib/active_record/tasks/database_tasks.rb
index ff388ff1f6..4657e51e6d 100644
--- a/activerecord/lib/active_record/tasks/database_tasks.rb
+++ b/activerecord/lib/active_record/tasks/database_tasks.rb
@@ -164,13 +164,12 @@ module ActiveRecord
       end
 
       def migrate
-        raise "Empty VERSION provided" if ENV["VERSION"] && ENV["VERSION"].empty?
+        check_target_version
 
         verbose = ENV["VERBOSE"] ? ENV["VERBOSE"] != "false" : true
-        version = ENV["VERSION"] ? ENV["VERSION"].to_i : nil
         scope = ENV["SCOPE"]
         verbose_was, Migration.verbose = Migration.verbose, verbose
-        Migrator.migrate(migrations_paths, version) do |migration|
+        Migrator.migrate(migrations_paths, target_version) do |migration|
           scope.blank? || scope == migration.scope
         end
         ActiveRecord::Base.clear_cache!
@@ -178,6 +177,16 @@ module ActiveRecord
         Migration.verbose = verbose_was
       end
 
+      def check_target_version
+        if target_version && !(Migration::MigrationFilenameRegexp.match?(ENV["VERSION"]) || /\A\d+\z/.match?(ENV["VERSION"]))
+          raise "Invalid format of target version: `VERSION=#{ENV['VERSION']}`"
+        end
+      end
+
+      def target_version
+        ENV["VERSION"].to_i if ENV["VERSION"] && !ENV["VERSION"].empty?
+      end
+
       def charset_current(environment = env)
         charset ActiveRecord::Base.configurations[environment]
       end