Hide label comments if labels were added and removed immediately (#17455)

* Hide label comments if labels were added and removed immediately

* Add comment and rename var

* Fix unit test

* Add test case

Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>

routers/web/repo/issue.go

@@ -2577,9 +2577,33 @@ func combineLabelComments(issue *models.Issue) {
 		if cur.Label != nil { // now cur MUST be label comment
 			if prev.Type == models.CommentTypeLabel { // we can combine them only prev is a label comment
 				if cur.Content != "1" {
-					prev.RemovedLabels = append(prev.RemovedLabels, cur.Label)
+					// remove labels from the AddedLabels list if the label that was removed is already
+					// in this list, and if it's not in this list, add the label to RemovedLabels
+					addedAndRemoved := false
+					for i, label := range prev.AddedLabels {
+						if cur.Label.ID == label.ID {
+							prev.AddedLabels = append(prev.AddedLabels[:i], prev.AddedLabels[i+1:]...)
+							addedAndRemoved = true
+							break
+						}
+					}
+					if !addedAndRemoved {
+						prev.RemovedLabels = append(prev.RemovedLabels, cur.Label)
+					}
 				} else {
-					prev.AddedLabels = append(prev.AddedLabels, cur.Label)
+					// remove labels from the RemovedLabels list if the label that was added is already
+					// in this list, and if it's not in this list, add the label to AddedLabels
+					removedAndAdded := false
+					for i, label := range prev.RemovedLabels {
+						if cur.Label.ID == label.ID {
+							prev.RemovedLabels = append(prev.RemovedLabels[:i], prev.RemovedLabels[i+1:]...)
+							removedAndAdded = true
+							break
+						}
+					}
+					if !removedAndAdded {
+						prev.AddedLabels = append(prev.AddedLabels, cur.Label)
+					}
 				}
 				prev.CreatedUnix = cur.CreatedUnix
 				// remove the current comment since it has been combined to prev comment

routers/web/repo/issue_test.go

@@ -51,16 +51,7 @@ func TestCombineLabelComments(t *testing.T) {
 					PosterID:    1,
 					Content:     "1",
 					CreatedUnix: 0,
-					AddedLabels: []*models.Label{
-						{
-							Name: "kind/bug",
-						},
-					},
-					RemovedLabels: []*models.Label{
-						{
-							Name: "kind/bug",
-						},
-					},
+					AddedLabels: []*models.Label{},
 					Label: &models.Label{
 						Name: "kind/bug",
 					},
@@ -310,6 +301,66 @@ func TestCombineLabelComments(t *testing.T) {
 				},
 			},
 		},
+		{
+			name: "kase 6",
+			beforeCombined: []*models.Comment{
+				{
+					Type:     models.CommentTypeLabel,
+					PosterID: 1,
+					Content:  "1",
+					Label: &models.Label{
+						Name: "kind/bug",
+					},
+					CreatedUnix: 0,
+				},
+				{
+					Type:     models.CommentTypeLabel,
+					PosterID: 1,
+					Content:  "1",
+					Label: &models.Label{
+						Name: "reviewed/confirmed",
+					},
+					CreatedUnix: 0,
+				},
+				{
+					Type:     models.CommentTypeLabel,
+					PosterID: 1,
+					Content:  "",
+					Label: &models.Label{
+						Name: "kind/bug",
+					},
+					CreatedUnix: 0,
+				},
+				{
+					Type:     models.CommentTypeLabel,
+					PosterID: 1,
+					Content:  "1",
+					Label: &models.Label{
+						Name: "kind/feature",
+					},
+					CreatedUnix: 0,
+				},
+			},
+			afterCombined: []*models.Comment{
+				{
+					Type:     models.CommentTypeLabel,
+					PosterID: 1,
+					Content:  "1",
+					Label: &models.Label{
+						Name: "kind/bug",
+					},
+					AddedLabels: []*models.Label{
+						{
+							Name: "reviewed/confirmed",
+						},
+						{
+							Name: "kind/feature",
+						},
+					},
+					CreatedUnix: 0,
+				},
+			},
+		},
 	}
 
 	for _, kase := range kases {