From 2eacf6fbc446620fecb30d58cac637d7826afcf8 Mon Sep 17 00:00:00 2001
From: Sebastiaan de Schaetzen <sebastiaan.de.schaetzen@gmail.com>
Date: Sun, 16 Mar 2025 11:38:31 +0100
Subject: [PATCH] Improve migration handling and error forwarding in deferred
 statements

---
 migrator.go   |  3 +++
 query.go      |  4 ++--
 query_test.go | 13 +++++++++++--
 util.go       |  7 +++++++
 4 files changed, 23 insertions(+), 4 deletions(-)
 create mode 100644 util.go

diff --git a/migrator.go b/migrator.go
index ce4af77..68bc011 100644
--- a/migrator.go
+++ b/migrator.go
@@ -74,6 +74,9 @@ func performSingleMigration(d *Db, migrationScript []byte, targetVersion int) er
 
 	for _, statement := range statements {
 		statement = strings.TrimSpace(statement)
+		if statement == "" {
+			continue
+		}
 		err = tx.Query(statement).Exec()
 		if err != nil {
 			return fmt.Errorf("error performing migration: %v", err)
diff --git a/query.go b/query.go
index 829b530..7e7aad4 100644
--- a/query.go
+++ b/query.go
@@ -58,7 +58,7 @@ func (q *Query) Exec() (rerr error) {
 	defer q.unlock()
 
 	if q.stmt != nil {
-		defer func() { rerr = q.stmt.Finalize() }()
+		defer func() { forwardError(q.stmt.Finalize(), &rerr) }()
 	}
 	if q.err != nil {
 		return q.err
@@ -84,7 +84,7 @@ func (q *Query) ScanSingle(results ...any) (rerr error) {
 	defer q.unlock()
 	// Scan rows
 	if q.stmt != nil {
-		defer func() { rerr = q.stmt.Finalize() }()
+		defer func() { forwardError(q.stmt.Finalize(), &rerr) }()
 	}
 	if q.err != nil {
 		return q.err
diff --git a/query_test.go b/query_test.go
index 355125e..0ea4ba0 100644
--- a/query_test.go
+++ b/query_test.go
@@ -73,11 +73,20 @@ func TestUpdateQuery(t *testing.T) {
 		tx := db.MustBegin()
 		defer tx.MustRollback()
 		tx.Query("insert into mytable(key, value) values ('lorem', 'bar')").MustExec()
-		tx.Query("update mytable set value = 'ipsum' where key = 'lorem'").MustExec()
+		value := "ipsum"
+		key := "lorem"
+		tx.Query("update mytable set value = ? where key = ?").Bind(value, key).MustExec()
 		tx.MustCommit()
 	}()
 
 	var value string
-	db.Query("select value from mytable where value = 'ipsum'").MustScanSingle(&value)
+	db.Query("select value from mytable where key = 'lorem'").MustScanSingle(&value)
 	require.Equal(t, "ipsum", value)
 }
+
+func TestUpdateQueryWithWrongArguments(t *testing.T) {
+	db := openTestDb(t)
+	value := "ipsum"
+	err := db.Query("insert into mytable(key, value) values ('lorem', ?)").Bind(&value).Exec()
+	require.Error(t, err)
+}
diff --git a/util.go b/util.go
new file mode 100644
index 0000000..148c965
--- /dev/null
+++ b/util.go
@@ -0,0 +1,7 @@
+package mysqlite
+
+func forwardError(from error, to *error) {
+	if from != nil {
+		*to = from
+	}
+}