Reject rowid-changing updates on virtual tables

sqlite3_opt_vtable_test.go

@@ -280,6 +280,19 @@ func TestVUpdate(t *testing.T) {
 		t.Fatalf("expected table vt entry 1 to be [117 f e], instead: %v", vt.data[1])
 	}
 
+	// a rowid-changing update cannot be expressed via VTabUpdater and
+	// must be rejected instead of updating the wrong row
+	_, err = db.Exec(`update vt set rowid = rowid + 10 where f1 = 117`)
+	if err == nil {
+		t.Fatalf("expected error on rowid-changing update, got nil")
+	}
+	if !strings.Contains(err.Error(), "does not support changing the rowid") {
+		t.Fatalf("unexpected error on rowid-changing update: %v", err)
+	}
+	if !reflect.DeepEqual(vt.data[1], []any{int64(117), "f", "e"}) {
+		t.Fatalf("expected table vt entry 1 to be unchanged, instead: %v", vt.data[1])
+	}
+
 	// delete from vt
 	res, err = db.Exec(`delete from vt where f1 = 117`)
 	if err != nil {