Fix potential bugs (#10513)

* use e if it is an option
* potential nil so check err first
* check err first
* m == nil already checked

4 files changed, 8 insertions, 4 deletions

diff --git a/models/action.go b/models/action.go
index 267a19bc62..fd49c6d4ed 100644
--- a/models/action.go
+++ b/models/action.go
@@ -213,7 +213,7 @@ func (a *Action) getCommentLink(e Engine) string {
 		return "#"
 	}
 	if a.Comment == nil && a.CommentID != 0 {
-		a.Comment, _ = GetCommentByID(a.CommentID)
+		a.Comment, _ = getCommentByID(e, a.CommentID)
 	}
 	if a.Comment != nil {
 		return a.Comment.HTMLURL()
diff --git a/models/attachment.go b/models/attachment.go
index 81f2e15dad..7e59c7eef4 100644
--- a/models/attachment.go
+++ b/models/attachment.go
@@ -199,7 +199,7 @@ func GetAttachmentsByCommentID(commentID int64) ([]*Attachment, error) {
 
 func getAttachmentsByCommentID(e Engine, commentID int64) ([]*Attachment, error) {
 	attachments := make([]*Attachment, 0, 10)
-	return attachments, x.Where("comment_id=?", commentID).Find(&attachments)
+	return attachments, e.Where("comment_id=?", commentID).Find(&attachments)
 }
 
 // getAttachmentByReleaseIDFileName return a file based on the the following infos:
diff --git a/models/issue_comment.go b/models/issue_comment.go
index 4abc3f9c1f..303cf3f9c1 100644
--- a/models/issue_comment.go
+++ b/models/issue_comment.go
@@ -765,8 +765,12 @@ func CreateRefComment(doer *User, repo *Repository, issue *Issue, content, commi
 
 // GetCommentByID returns the comment by given ID.
 func GetCommentByID(id int64) (*Comment, error) {
+	return getCommentByID(x, id)
+}
+
+func getCommentByID(e Engine, id int64) (*Comment, error) {
 	c := new(Comment)
-	has, err := x.ID(id).Get(c)
+	has, err := e.ID(id).Get(c)
 	if err != nil {
 		return nil, err
 	} else if !has {
diff --git a/models/notification.go b/models/notification.go
index c52d6c557a..a7a65c38a4 100644
--- a/models/notification.go
+++ b/models/notification.go
@@ -396,7 +396,7 @@ func (n *Notification) loadIssue(e Engine) (err error) {
 
 func (n *Notification) loadComment(e Engine) (err error) {
 	if n.Comment == nil && n.CommentID > 0 {
-		n.Comment, err = GetCommentByID(n.CommentID)
+		n.Comment, err = getCommentByID(e, n.CommentID)
 		if err != nil {
 			return fmt.Errorf("GetCommentByID [%d] for issue ID [%d]: %v", n.CommentID, n.IssueID, err)
 		}