clean up migrations ordering

util/src/migration/mod.rs

@@ -180,12 +180,11 @@ impl Manager {
 
 	/// Adds new migration rules.
 	pub fn add_migration<T>(&mut self, migration: T) -> Result<(), Error> where T: Migration {
-		let version_match = match self.migrations.last() {
-			Some(last) => last.version() + 1 == migration.version(),
+		let is_new = match self.migrations.last() {
+			Some(last) => migration.version() > last.version(),
 			None => true,
 		};
-
-		match version_match {
+		match is_new {
 			true => Ok(self.migrations.push(Box::new(migration))),
 			false => Err(Error::CannotAddMigration),
 		}
@@ -238,9 +237,7 @@ impl Manager {
 
 	/// Find all needed migrations and arrange them.
 	fn migrations_from(&mut self, version: u32) -> Vec<&mut Box<Migration>> {
-		let mut to_apply: Vec<_> = self.migrations.iter_mut().filter(|m| m.version() > version).collect();
-		to_apply.sort_by_key(|m| m.version());
-		to_apply
+		self.migrations.iter_mut().filter(|m| m.version() > version).collect()
 	}
 }
 

util/src/migration/tests.rs

@@ -109,6 +109,18 @@ fn no_migration_needed() {
 	manager.execute(&db_path, 1).unwrap();
 }
 
+#[test]
+#[should_panic]
+fn wrong_adding_order() {
+	let dir = RandomTempPath::create_dir();
+	let db_path = db_path(dir.as_path());
+	let mut manager = Manager::new(Config::default());
+	make_db(&db_path, map![vec![] => vec![], vec![1] => vec![1]]);
+
+	manager.add_migration(Migration1).unwrap();
+	manager.add_migration(Migration0).unwrap();
+}
+
 #[test]
 fn multiple_migrations() {
 	let dir = RandomTempPath::create_dir();