Improved type casting in the appender

appender.go

@@ -8,7 +8,6 @@ import "C"
 
 import (
 	"database/sql/driver"
-	"reflect"
 	"unsafe"
 )
 
@@ -187,18 +186,17 @@ func (a *Appender) newDataChunk(colCount int) {
 }
 
 func (a *Appender) appendRowSlice(args []driver.Value) error {
-	for i, v := range args {
+	for i, val := range args {
 		vec := a.vectors[i]
-		if v == nil {
-			vec.setNull(a.currSize)
-			continue
-		}
 
 		// Ensure that the types match before attempting to append anything.
-		if err := vec.typeMatch(reflect.TypeOf(v)); err != nil {
+		v, err := vec.tryCast(val)
+		if err != nil {
 			// Use 1-based indexing for readability, as we're talking about columns.
 			return columnError(err, i+1)
 		}
+
+		// Append the row to the data chunk.
 		vec.fn(&vec, a.currSize, v)
 	}
 

appender_test.go

@@ -4,6 +4,7 @@ import (
 	"context"
 	"database/sql"
 	"database/sql/driver"
+	"encoding/json"
 	"fmt"
 	"math/rand"
 	"testing"
@@ -761,3 +762,40 @@ func TestAppenderUint8SliceTinyInt(t *testing.T) {
 	require.NoError(t, res.Close())
 	cleanupAppender(t, c, con, a)
 }
+
+func TestAppenderWithJSON(t *testing.T) {
+	c, con, a := prepareAppender(t, `
+		CREATE TABLE test (
+		    id DOUBLE,
+			l DOUBLE[],
+			s STRUCT(a DOUBLE, b VARCHAR)
+	  	)`)
+
+	jsonBytes := []byte(`{"id": 42, "l":[1, 2, 3], "s":{"a":101, "b":"hello"}}`)
+	var jsonData map[string]interface{}
+	err := json.Unmarshal(jsonBytes, &jsonData)
+	require.NoError(t, err)
+
+	require.NoError(t, a.AppendRow(jsonData["id"], jsonData["l"], jsonData["s"]))
+	require.NoError(t, a.Flush())
+
+	// Verify results.
+	res, err := sql.OpenDB(c).QueryContext(context.Background(), `SELECT * FROM test`)
+	require.NoError(t, err)
+
+	for res.Next() {
+		var (
+			id uint64
+			l  interface{}
+			s  interface{}
+		)
+		err := res.Scan(&id, &l, &s)
+		require.NoError(t, err)
+		require.Equal(t, uint64(42), id)
+		require.Equal(t, "[1 2 3]", fmt.Sprint(l))
+		require.Equal(t, "map[a:101 b:hello]", fmt.Sprint(s))
+	}
+
+	require.NoError(t, res.Close())
+	cleanupAppender(t, c, con, a)
+}