Fix yet another pointer

Reviewed-on: #1

errors.go

@@ -0,0 +1,5 @@
+package mysqlite
+
+import "errors"
+
+var ErrNoRows = errors.New("mysqlite: no rows returned")

migrator.go

@@ -42,7 +42,7 @@ func (d *Db) MigrateDb(filesystem ReadDirFileFS, directory string) error {
 	log.Printf("Current version is %d, max migration version is %d", currentVersion, latestVersion)
 
 	// Create a backup if we're not on the latest version
-	if currentVersion != latestVersion && d.source != ":memory:" {
+	if currentVersion != 0 && currentVersion != latestVersion && d.source != ":memory:" {
 		target := d.source + ".backup." + strconv.Itoa(currentVersion)
 		log.Printf("Creating backup of database to %s", target)
 		data, err := d.Db.Serialize("main")

query.go

@@ -44,6 +44,18 @@ func (q *Query) bindInto(into *int, args ...any) *Query {
 	}
 	for i, arg := range args {
 		*into++
+		if arg == nil {
+			q.stmt.BindNull(*into)
+			continue
+		}
+		v := reflect.ValueOf(arg)
+		if v.Kind() == reflect.Ptr {
+			if v.IsNil() {
+				q.stmt.BindNull(*into)
+				continue
+			}
+			arg = v.Elem().Interface()
+		}
 		if asString, ok := arg.(string); ok {
 			q.stmt.BindText(*into, asString)
 		} else if asInt, ok := arg.(int); ok {
@@ -54,7 +66,7 @@ func (q *Query) bindInto(into *int, args ...any) *Query {
 			q.stmt.BindBool(*into, asBool)
 		} else {
 			// Check if the argument is a slice or array of any type
-			v := reflect.ValueOf(arg)
+			v = reflect.ValueOf(arg)
 			if v.Kind() == reflect.Slice || v.Kind() == reflect.Array {
 				*into--
 				for i := 0; i < v.Len(); i++ {
@@ -116,7 +128,7 @@ func (q *Query) ScanSingle(results ...any) (rerr error) {
 		return err
 	}
 	if !hasResult {
-		return fmt.Errorf("did not return any rows")
+		return ErrNoRows
 	}
 
 	// Scan its columns

query_test.go

@@ -1,6 +1,7 @@
 package mysqlite
 
 import (
+	"errors"
 	"github.com/stretchr/testify/require"
 	"testing"
 )
@@ -19,6 +20,14 @@ func TestSimpleQuery(t *testing.T) {
 	require.Equal(t, 1, count, "expected empty count")
 }
 
+func TestSimpleQueryWithNoResults(t *testing.T) {
+	db := openTestDb(t)
+	var count int
+	err := db.Query("select 1 from mytable where key=999").ScanSingle(&count)
+	require.Equal(t, ErrNoRows, err)
+	require.True(t, errors.Is(err, ErrNoRows))
+}
+
 func TestSimpleQueryWithArgs(t *testing.T) {
 	db := openTestDb(t)
 	var value string
@@ -85,12 +94,70 @@ func TestUpdateQuery(t *testing.T) {
 }
 
 func TestUpdateQueryWithWrongArguments(t *testing.T) {
+	type S struct {
+		Field string
+	}
 	db := openTestDb(t)
-	value := "ipsum"
+	abc := S{
-	err := db.Query("insert into mytable(key, value) values ('lorem', ?)").Bind(&value).Exec()
+		Field: "ipsum",
+	}
+	err := db.Query("insert into mytable(key, value) values ('lorem', ?)").Bind(abc).Exec()
 	require.Error(t, err)
 }
 
+func TestUpdateQueryWithPointerValue(t *testing.T) {
+	db := openTestDb(t)
+	func() {
+		tx := db.MustBegin()
+		defer tx.MustRollback()
+		tx.Query("insert into mytable(key, value) values ('lorem', 'bar')").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 key = 'lorem'").MustScanSingle(&value)
+	require.Equal(t, "ipsum", value)
+}
+
+func TestUpdateQueryWithSetPointerValue(t *testing.T) {
+	type S struct {
+		value *string
+	}
+	db := openTestDb(t)
+	func() {
+		tx := db.MustBegin()
+		defer tx.MustRollback()
+		tx.Query("insert into mytable(key, value) values ('lorem', 'bar')").MustExec()
+		s := S{nil}
+		key := "lorem"
+		tx.Query("update mytable set value = ? where key = ?").Bind(s.value, key).MustExec()
+		tx.MustCommit()
+	}()
+
+	var value *string
+	db.Query("select value from mytable where key = 'lorem'").MustScanSingle(&value)
+	require.Equal(t, (*string)(nil), value)
+}
+
+func TestUpdateQueryWithNullValue(t *testing.T) {
+	db := openTestDb(t)
+	func() {
+		tx := db.MustBegin()
+		defer tx.MustRollback()
+		tx.Query("insert into mytable(key, value) values ('lorem', 'bar')").MustExec()
+		key := "lorem"
+		tx.Query("update mytable set value = ? where key = ?").Bind(nil, key).MustExec()
+		tx.MustCommit()
+	}()
+
+	var value *string
+	db.Query("select value from mytable where key = 'lorem'").MustScanSingle(&value)
+	require.Nil(t, value)
+}
+
 func TestQueryWithPointerStringArguments(t *testing.T) {
 	db := openTestDb(t)
 	var result *string
@@ -102,7 +169,7 @@ func TestQueryWithPointerStringArguments(t *testing.T) {
 
 func TestQueryWithPointerStringArgumentsCanSetToNull(t *testing.T) {
 	db := openTestDb(t)
-	db.Query("update mytable set value=NULL where key = 'foo'").MustExec()
+	db.Query("update mytable set value=null where key = 'foo'").MustExec()
 	myString := "some string"
 	var result *string
 	result = &myString