fix(issues): fix label bulk-load key and reduce log noise in LoadLabel (#38632) (#38643)

Backport #38632 by @eliroca

CommentList.loadLabels keyed the result map by label.ID but looked up by
comment.ID, so every label event fell back to individual DB queries.

This caused log spam for any comment where the label was deleted, since
ToTimelineComment calls LoadLabel unconditionally for all comment types
including those with LabelID=0.

Fix the map key, skip the query when LabelID=0, demote the now rarely
triggered orphaned-label log to Debug, and fix a typo ("Commit" ->
"Comment") in that message.

Signed-off-by: wxiaoguang <wxiaoguang@gmail.com>
Co-authored-by: Elisei Roca <eroca@suse.de>
Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>

models/issues/comment.go

@@ -544,6 +544,9 @@ func (c *Comment) GetSanitizedContentHTML() template.HTML {
 
 // LoadLabel if comment.Type is CommentTypeLabel, then load Label
 func (c *Comment) LoadLabel(ctx context.Context) error {
+	if c.LabelID == 0 {
+		return nil
+	}
 	var label Label
 	has, err := db.GetEngine(ctx).ID(c.LabelID).Get(&label)
 	if err != nil {
@@ -551,8 +554,8 @@ func (c *Comment) LoadLabel(ctx context.Context) error {
 	} else if has {
 		c.Label = &label
 	} else {
-		// Ignore Label is deleted, but not clear this table
+		// label was deleted but comment rows referencing it were not cleaned up
-		log.Warn("Commit %d cannot load label %d", c.ID, c.LabelID)
+		log.Debug("Comment %d references deleted label %d", c.ID, c.LabelID)
 	}
 
 	return nil

models/issues/comment_list.go

@@ -81,7 +81,7 @@ func (comments CommentList) loadLabels(ctx context.Context) error {
 	}
 
 	for _, comment := range comments {
-		comment.Label = commentLabels[comment.ID]
+		comment.Label = commentLabels[comment.LabelID]
 	}
 	return nil
 }