Discussion #250.

conn.go

@@ -343,6 +343,9 @@ func (c *Conn) GetInterrupt() context.Context {
 //
 // https://sqlite.org/c3ref/interrupt.html
 func (c *Conn) SetInterrupt(ctx context.Context) (old context.Context) {
+	if ctx == nil {
+		panic("nil Context")
+	}
 	old = c.interrupt
 	c.interrupt = ctx
 	return old
@@ -406,11 +409,8 @@ func (c *Conn) BusyHandler(cb func(ctx context.Context, count int) (retry bool))
 
 func busyCallback(ctx context.Context, mod api.Module, pDB ptr_t, count int32) (retry int32) {
 	if c, ok := ctx.Value(connKey{}).(*Conn); ok && c.handle == pDB && c.busy != nil {
-		interrupt := c.interrupt
-		if interrupt == nil {
-			interrupt = context.Background()
-		}
-		if interrupt.Err() == nil && c.busy(interrupt, int(count)) {
+		if interrupt := c.interrupt; interrupt.Err() == nil &&
+			c.busy(interrupt, int(count)) {
 			retry = 1
 		}
 	}

driver/driver.go

@@ -358,13 +358,10 @@ func (c *conn) Commit() error {
 }
 
 func (c *conn) Rollback() error {
-	err := c.Conn.Exec(`ROLLBACK` + c.txReset)
-	if errors.Is(err, sqlite3.INTERRUPT) {
+	// ROLLBACK even if interrupted.
 	old := c.Conn.SetInterrupt(context.Background())
 	defer c.Conn.SetInterrupt(old)
-		err = c.Conn.Exec(`ROLLBACK` + c.txReset)
-	}
-	return err
+	return c.Conn.Exec(`ROLLBACK` + c.txReset)
 }
 
 func (c *conn) Prepare(query string) (driver.Stmt, error) {

tests/conn_test.go

@@ -146,10 +146,7 @@ func TestConn_SetInterrupt(t *testing.T) {
 	}
 	defer stmt.Close()
 
-	go func() {
-		time.Sleep(time.Millisecond)
-		cancel()
-	}()
+	time.AfterFunc(time.Millisecond, cancel)
 
 	// Interrupting works.
 	err = stmt.Exec()

txn.go

@@ -20,6 +20,8 @@ type Txn struct {
 }
 
 // Begin starts a deferred transaction.
+// Panics if a transaction is already in-progress.
+// For nested transactions, use [Conn.Savepoint].
 //
 // https://sqlite.org/lang_transaction.html
 func (c *Conn) Begin() Txn {
@@ -119,6 +121,7 @@ func (tx Txn) Commit() error {
 //
 // https://sqlite.org/lang_transaction.html
 func (tx Txn) Rollback() error {
+	// ROLLBACK even if interrupted.
 	return tx.c.exec(`ROLLBACK`)
 }