Don't error when target version has no migrations left to apply

migrate.go

@@ -680,7 +680,9 @@ func (ms MigrationSet) planMigrationCommon(db *sql.DB, dialect string, m Migrati
 	toApply := ToApply(migrations, record.Id, dir)
 	toApplyCount := len(toApply)
 
-	if version >= 0 {
+	// When a target version is requested but there are no migrations left to
+	// apply, we are already at that version, so there is nothing to do.
+	if version >= 0 && len(toApply) > 0 {
 		targetIndex := 0
 		for targetIndex < len(toApply) {
 			tempVersion := toApply[targetIndex].VersionInt()

migrate_test.go

@@ -229,6 +229,22 @@ func (s *SqliteMigrateSuite) TestMigrateVersionIntFailedWithInvalidVerion(c *C)
 	c.Assert(err, NotNil)
 }
 
+func (s *SqliteMigrateSuite) TestMigrateVersionIntAlreadyAtVersion(c *C) {
+	migrations := &FileMigrationSource{
+		Dir: "test-migrations",
+	}
+
+	// Migrate up to the latest version.
+	n, err := ExecVersion(s.Db, "sqlite3", migrations, Up, 2)
+	c.Assert(err, IsNil)
+	c.Assert(n, Equals, 2)
+
+	// Requesting the same version again has nothing to apply and must not error.
+	n, err = ExecVersion(s.Db, "sqlite3", migrations, Up, 2)
+	c.Assert(err, IsNil)
+	c.Assert(n, Equals, 0)
+}
+
 func (s *SqliteMigrateSuite) TestMigrateDown(c *C) {
 	migrations := &FileMigrationSource{
 		Dir: "test-migrations",