comment updates for gdb.Builder (#2513)

contrib/drivers/mysql/mysql_feature_model_builder_test.go

@@ -125,3 +125,17 @@ func Test_Model_Builder(t *testing.T) {
 		t.Assert(args, []interface{}{1})
 	})
 }
+
+func Test_Safe_Builder(t *testing.T) {
+	// test whether m.Builder() is chain safe
+	gtest.C(t, func(t *gtest.T) {
+		b := db.Model().Builder()
+		b.Where("id", 1)
+		_, args := b.Build()
+		t.AssertNil(args)
+
+		b = b.Where("id", 1)
+		_, args = b.Build()
+		t.Assert(args, g.Slice{1})
+	})
+}

database/gdb/gdb_model_builder.go

@@ -25,7 +25,7 @@ type WhereHolder struct {
 	Prefix   string        // Field prefix, eg: "user.", "order.".
 }
 
-// Builder creates and returns a WhereBuilder.
+// Builder creates and returns a WhereBuilder. Please note that the builder is chain-safe.
 func (m *Model) Builder() *WhereBuilder {
 	b := &WhereBuilder{
 		model:       m,
@@ -34,8 +34,7 @@ func (m *Model) Builder() *WhereBuilder {
 	return b
 }
 
-// getBuilder creates and returns a cloned WhereBuilder of current WhereBuilder if `safe` is true,
-// or else it returns the current WhereBuilder.
+// getBuilder creates and returns a cloned WhereBuilder of current WhereBuilder
 func (b *WhereBuilder) getBuilder() *WhereBuilder {
 	return b.Clone()
 }