fix(bun): spread variadic args correctly in ColumnExpr

pkg/common/adapters/database/bun.go

@@ -339,7 +339,7 @@ func (b *BunSelectQuery) Column(columns ...string) common.SelectQuery {
 
 func (b *BunSelectQuery) ColumnExpr(query string, args ...interface{}) common.SelectQuery {
 	if len(args) > 0 {
-		b.query = b.query.ColumnExpr(query, args)
+		b.query = b.query.ColumnExpr(query, args...)
 	} else {
 		b.query = b.query.ColumnExpr(query)
 	}

pkg/common/adapters/database/bun_columnexpr_test.go

@@ -0,0 +1,31 @@
+package database
+
+import (
+	"strings"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+// TestBunSelectQuery_ColumnExpr_SpreadsArgs is a regression test for a bug
+// where ColumnExpr passed its variadic args slice as a single argument
+// (b.query.ColumnExpr(query, args) instead of args...), causing bun to
+// serialize the arg slice itself (e.g. producing `'["{product,cost}"]'`
+// instead of `'{product,cost}'` for a JSON path parameter).
+func TestBunSelectQuery_ColumnExpr_SpreadsArgs(t *testing.T) {
+	db := setupBunTestDB(t)
+	defer db.Close()
+
+	adapter := NewBunAdapter(db)
+
+	sq := adapter.NewSelect().
+		Table("test_inserts").
+		ColumnExpr("(jsonvalue #>> ?::text[]) AS jsonvalue_product_cost", "{product,cost}")
+
+	bsq, ok := sq.(*BunSelectQuery)
+	require.True(t, ok, "expected *BunSelectQuery")
+
+	sqlStr := bsq.query.String()
+	require.NotContains(t, sqlStr, `["{product,cost}"]`, "arg slice must not be serialized as a JSON array: %s", sqlStr)
+	require.True(t, strings.Contains(sqlStr, `'{product,cost}'`), "expected the bound text[] literal in SQL: %s", sqlStr)
+}