fix: exclude unexported default fields

document.go

@@ -49,33 +49,45 @@ type IDefaultSchema interface {
 // DefaultSchema is a struct that implements the IDefaultSchema interface.
 // It contains the default fields (ID,CreatedAt,UpdatedAt) that are added to a document.
 type DefaultSchema struct {
-	ID        primitive.ObjectID `json:"_id,omitempty"       bson:"_id,omitempty"`
-	CreatedAt time.Time          `json:"createdAt,omitempty" bson:"createdAt,omitempty"`
-	UpdatedAt time.Time          `json:"updatedAt,omitempty" bson:"updatedAt,omitempty"`
+	ID        *primitive.ObjectID `json:"_id,omitempty"       bson:"_id,omitempty"`
+	CreatedAt *time.Time          `json:"createdAt,omitempty" bson:"createdAt,omitempty"`
+	UpdatedAt *time.Time          `json:"updatedAt,omitempty" bson:"updatedAt,omitempty"`
 }
 
 func (s *DefaultSchema) GenerateID() {
-	s.ID = primitive.NewObjectID()
+	id := primitive.NewObjectID()
+	s.ID = &id
 }
 
 func (s *DefaultSchema) GenerateCreatedAt() {
-	s.CreatedAt = time.Now()
+	c := time.Now()
+	s.CreatedAt = &c
 }
 
 func (s *DefaultSchema) GenerateUpdatedAt() {
-	s.UpdatedAt = time.Now()
+	u := time.Now()
+	s.UpdatedAt = &u
 }
 
 func (s DefaultSchema) GetID() primitive.ObjectID {
-	return s.ID
+	if s.ID == nil {
+		return primitive.NilObjectID
+	}
+	return *s.ID
 }
 
 func (s DefaultSchema) GetCreatedAt() time.Time {
-	return s.CreatedAt
+	if s.CreatedAt == nil {
+		return time.Time{}
+	}
+	return *s.CreatedAt
 }
 
 func (s DefaultSchema) GetUpdatedAt() time.Time {
-	return s.UpdatedAt
+	if s.UpdatedAt == nil {
+		return time.Time{}
+	}
+	return *s.UpdatedAt
 }
 
 func (s DefaultSchema) GetUpdatedAtTag(t string) string {
@@ -91,7 +103,7 @@ func (s DefaultSchema) GetUpdatedAtTag(t string) string {
 // }
 
 func (s *DefaultSchema) SetUpdatedAt(t time.Time) {
-	s.UpdatedAt = t
+	s.UpdatedAt = &t
 }
 
 // Document is a struct that represents a document in a MongoDB collection.

model.go

@@ -13,8 +13,10 @@ import (
 	"go.mongodb.org/mongo-driver/mongo/options"
 )
 
+// SessionFunc is a callback function that's executed within a session transaction.
 type SessionFunc func(sessCtx mongo.SessionContext) (interface{}, error)
 
+// SessionLike is a Union type of all mongo types that a seeion can be derived from.
 type SessionLike interface {
 	*mongo.Database | *mongo.Collection | *mongo.SessionContext | *mongo.Client | *mongo.Session
 }
@@ -424,6 +426,7 @@ func (model *Model[T, P]) UpdateMany(ctx context.Context, query bson.M, update b
 
 // WithTransaction executes the callback function in a transaction.
 // When a transaction is started with [mongo.SessionContext] options are ignored because the session is already created.
+// This method only closes the session if it was created by this method.
 func WithTransaction[T SessionLike](ctx context.Context, sess T, fn SessionFunc, opts ...*options.TransactionOptions) (any, error) {
 	var session mongo.Session
 	var err error