From e6acce649b348cc497b999100a170866a90c87b8 Mon Sep 17 00:00:00 2001
From: Jimmy Praet <jimmy.praet@telenet.be>
Date: Sat, 2 Jan 2021 18:04:02 +0100
Subject: [PATCH] Send notifications for mentions in pulls, issues,
 (code-)comments (#14218)

Fixes #14187: mention handling extracted from email notification code
Fixes #14013: add notification for mentions in pull request code comments
Fixes #13450: Not receiving any emails with setting "Only Email on Mention"
---
 models/issue.go                         | 14 +++++++
 modules/notification/action/action.go   |  8 ++--
 modules/notification/base/notifier.go   | 11 ++---
 modules/notification/base/null.go       | 12 ++++--
 modules/notification/indexer/indexer.go |  6 +--
 modules/notification/mail/mail.go       | 28 ++++++++-----
 modules/notification/notification.go    | 23 +++++++----
 modules/notification/ui/ui.go           | 55 +++++++++++++++++++++++--
 modules/notification/webhook/webhook.go |  8 ++--
 services/comments/comments.go           |  7 +++-
 services/issue/issue.go                 |  7 +++-
 services/mailer/mail_comment.go         | 46 +++++++++++++--------
 services/mailer/mail_issue.go           | 34 ++++++---------
 services/pull/pull.go                   |  7 +++-
 services/pull/review.go                 | 27 +++++++++++-
 15 files changed, 205 insertions(+), 88 deletions(-)

diff --git a/models/issue.go b/models/issue.go
index eb47a74091..18d01d57d4 100644
--- a/models/issue.go
+++ b/models/issue.go
@@ -14,6 +14,7 @@ import (
 
 	"code.gitea.io/gitea/modules/base"
 	"code.gitea.io/gitea/modules/log"
+	"code.gitea.io/gitea/modules/references"
 	"code.gitea.io/gitea/modules/setting"
 	"code.gitea.io/gitea/modules/structs"
 	api "code.gitea.io/gitea/modules/structs"
@@ -1848,6 +1849,19 @@ func (issue *Issue) updateClosedNum(e Engine) (err error) {
 	return
 }
 
+// FindAndUpdateIssueMentions finds users mentioned in the given content string, and saves them in the database.
+func (issue *Issue) FindAndUpdateIssueMentions(ctx DBContext, doer *User, content string) (mentions []*User, err error) {
+	rawMentions := references.FindAllMentionsMarkdown(content)
+	mentions, err = issue.ResolveMentionsByVisibility(ctx, doer, rawMentions)
+	if err != nil {
+		return nil, fmt.Errorf("UpdateIssueMentions [%d]: %v", issue.ID, err)
+	}
+	if err = UpdateIssueMentions(ctx, issue.ID, mentions); err != nil {
+		return nil, fmt.Errorf("UpdateIssueMentions [%d]: %v", issue.ID, err)
+	}
+	return
+}
+
 // ResolveMentionsByVisibility returns the users mentioned in an issue, removing those that
 // don't have access to reading it. Teams are expanded into their users, but organizations are ignored.
 func (issue *Issue) ResolveMentionsByVisibility(ctx DBContext, doer *User, mentions []string) (users []*User, err error) {
diff --git a/modules/notification/action/action.go b/modules/notification/action/action.go
index 75d2aa3019..360906f076 100644
--- a/modules/notification/action/action.go
+++ b/modules/notification/action/action.go
@@ -29,7 +29,7 @@ func NewNotifier() base.Notifier {
 	return &actionNotifier{}
 }
 
-func (a *actionNotifier) NotifyNewIssue(issue *models.Issue) {
+func (a *actionNotifier) NotifyNewIssue(issue *models.Issue, mentions []*models.User) {
 	if err := issue.LoadPoster(); err != nil {
 		log.Error("issue.LoadPoster: %v", err)
 		return
@@ -88,7 +88,7 @@ func (a *actionNotifier) NotifyIssueChangeStatus(doer *models.User, issue *model
 
 // NotifyCreateIssueComment notifies comment on an issue to notifiers
 func (a *actionNotifier) NotifyCreateIssueComment(doer *models.User, repo *models.Repository,
-	issue *models.Issue, comment *models.Comment) {
+	issue *models.Issue, comment *models.Comment, mentions []*models.User) {
 	act := &models.Action{
 		ActUserID: doer.ID,
 		ActUser:   doer,
@@ -120,7 +120,7 @@ func (a *actionNotifier) NotifyCreateIssueComment(doer *models.User, repo *model
 	}
 }
 
-func (a *actionNotifier) NotifyNewPullRequest(pull *models.PullRequest) {
+func (a *actionNotifier) NotifyNewPullRequest(pull *models.PullRequest, mentions []*models.User) {
 	if err := pull.LoadIssue(); err != nil {
 		log.Error("pull.LoadIssue: %v", err)
 		return
@@ -203,7 +203,7 @@ func (a *actionNotifier) NotifyForkRepository(doer *models.User, oldRepo, repo *
 	}
 }
 
-func (a *actionNotifier) NotifyPullRequestReview(pr *models.PullRequest, review *models.Review, comment *models.Comment) {
+func (a *actionNotifier) NotifyPullRequestReview(pr *models.PullRequest, review *models.Review, comment *models.Comment, mentions []*models.User) {
 	if err := review.LoadReviewer(); err != nil {
 		log.Error("LoadReviewer '%d/%d': %v", review.ID, review.ReviewerID, err)
 		return
diff --git a/modules/notification/base/notifier.go b/modules/notification/base/notifier.go
index 7b8eb7b1f1..b01026dfc5 100644
--- a/modules/notification/base/notifier.go
+++ b/modules/notification/base/notifier.go
@@ -20,7 +20,7 @@ type Notifier interface {
 	NotifyRenameRepository(doer *models.User, repo *models.Repository, oldRepoName string)
 	NotifyTransferRepository(doer *models.User, repo *models.Repository, oldOwnerName string)
 
-	NotifyNewIssue(*models.Issue)
+	NotifyNewIssue(issue *models.Issue, mentions []*models.User)
 	NotifyIssueChangeStatus(*models.User, *models.Issue, *models.Comment, bool)
 	NotifyIssueChangeMilestone(doer *models.User, issue *models.Issue, oldMilestoneID int64)
 	NotifyIssueChangeAssignee(doer *models.User, issue *models.Issue, assignee *models.User, removed bool, comment *models.Comment)
@@ -32,15 +32,16 @@ type Notifier interface {
 	NotifyIssueChangeLabels(doer *models.User, issue *models.Issue,
 		addedLabels []*models.Label, removedLabels []*models.Label)
 
-	NotifyNewPullRequest(*models.PullRequest)
+	NotifyNewPullRequest(pr *models.PullRequest, mentions []*models.User)
 	NotifyMergePullRequest(*models.PullRequest, *models.User)
 	NotifyPullRequestSynchronized(doer *models.User, pr *models.PullRequest)
-	NotifyPullRequestReview(*models.PullRequest, *models.Review, *models.Comment)
+	NotifyPullRequestReview(pr *models.PullRequest, review *models.Review, comment *models.Comment, mentions []*models.User)
+	NotifyPullRequestCodeComment(pr *models.PullRequest, comment *models.Comment, mentions []*models.User)
 	NotifyPullRequestChangeTargetBranch(doer *models.User, pr *models.PullRequest, oldBranch string)
 	NotifyPullRequestPushCommits(doer *models.User, pr *models.PullRequest, comment *models.Comment)
 
-	NotifyCreateIssueComment(*models.User, *models.Repository,
-		*models.Issue, *models.Comment)
+	NotifyCreateIssueComment(doer *models.User, repo *models.Repository,
+		issue *models.Issue, comment *models.Comment, mentions []*models.User)
 	NotifyUpdateComment(*models.User, *models.Comment, string)
 	NotifyDeleteComment(*models.User, *models.Comment)
 
diff --git a/modules/notification/base/null.go b/modules/notification/base/null.go
index 7a9ad0b2ce..d80ba859f3 100644
--- a/modules/notification/base/null.go
+++ b/modules/notification/base/null.go
@@ -23,11 +23,11 @@ func (*NullNotifier) Run() {
 
 // NotifyCreateIssueComment places a place holder function
 func (*NullNotifier) NotifyCreateIssueComment(doer *models.User, repo *models.Repository,
-	issue *models.Issue, comment *models.Comment) {
+	issue *models.Issue, comment *models.Comment, mentions []*models.User) {
 }
 
 // NotifyNewIssue places a place holder function
-func (*NullNotifier) NotifyNewIssue(issue *models.Issue) {
+func (*NullNotifier) NotifyNewIssue(issue *models.Issue, mentions []*models.User) {
 }
 
 // NotifyIssueChangeStatus places a place holder function
@@ -35,11 +35,15 @@ func (*NullNotifier) NotifyIssueChangeStatus(doer *models.User, issue *models.Is
 }
 
 // NotifyNewPullRequest places a place holder function
-func (*NullNotifier) NotifyNewPullRequest(pr *models.PullRequest) {
+func (*NullNotifier) NotifyNewPullRequest(pr *models.PullRequest, mentions []*models.User) {
 }
 
 // NotifyPullRequestReview places a place holder function
-func (*NullNotifier) NotifyPullRequestReview(pr *models.PullRequest, r *models.Review, comment *models.Comment) {
+func (*NullNotifier) NotifyPullRequestReview(pr *models.PullRequest, r *models.Review, comment *models.Comment, mentions []*models.User) {
+}
+
+// NotifyPullRequestCodeComment places a place holder function
+func (*NullNotifier) NotifyPullRequestCodeComment(pr *models.PullRequest, comment *models.Comment, mentions []*models.User) {
 }
 
 // NotifyMergePullRequest places a place holder function
diff --git a/modules/notification/indexer/indexer.go b/modules/notification/indexer/indexer.go
index 8293d28570..205194ad3e 100644
--- a/modules/notification/indexer/indexer.go
+++ b/modules/notification/indexer/indexer.go
@@ -30,7 +30,7 @@ func NewNotifier() base.Notifier {
 }
 
 func (r *indexerNotifier) NotifyCreateIssueComment(doer *models.User, repo *models.Repository,
-	issue *models.Issue, comment *models.Comment) {
+	issue *models.Issue, comment *models.Comment, mentions []*models.User) {
 	if comment.Type == models.CommentTypeComment {
 		if issue.Comments == nil {
 			if err := issue.LoadDiscussComments(); err != nil {
@@ -45,11 +45,11 @@ func (r *indexerNotifier) NotifyCreateIssueComment(doer *models.User, repo *mode
 	}
 }
 
-func (r *indexerNotifier) NotifyNewIssue(issue *models.Issue) {
+func (r *indexerNotifier) NotifyNewIssue(issue *models.Issue, mentions []*models.User) {
 	issue_indexer.UpdateIssueIndexer(issue)
 }
 
-func (r *indexerNotifier) NotifyNewPullRequest(pr *models.PullRequest) {
+func (r *indexerNotifier) NotifyNewPullRequest(pr *models.PullRequest, mentions []*models.User) {
 	issue_indexer.UpdateIssueIndexer(pr.Issue)
 }
 
diff --git a/modules/notification/mail/mail.go b/modules/notification/mail/mail.go
index 847a2f30a7..ee8a0c436c 100644
--- a/modules/notification/mail/mail.go
+++ b/modules/notification/mail/mail.go
@@ -27,7 +27,7 @@ func NewNotifier() base.Notifier {
 }
 
 func (m *mailNotifier) NotifyCreateIssueComment(doer *models.User, repo *models.Repository,
-	issue *models.Issue, comment *models.Comment) {
+	issue *models.Issue, comment *models.Comment, mentions []*models.User) {
 	var act models.ActionType
 	if comment.Type == models.CommentTypeClose {
 		act = models.ActionCloseIssue
@@ -41,13 +41,13 @@ func (m *mailNotifier) NotifyCreateIssueComment(doer *models.User, repo *models.
 		act = 0
 	}
 
-	if err := mailer.MailParticipantsComment(comment, act, issue); err != nil {
+	if err := mailer.MailParticipantsComment(comment, act, issue, mentions); err != nil {
 		log.Error("MailParticipantsComment: %v", err)
 	}
 }
 
-func (m *mailNotifier) NotifyNewIssue(issue *models.Issue) {
-	if err := mailer.MailParticipants(issue, issue.Poster, models.ActionCreateIssue); err != nil {
+func (m *mailNotifier) NotifyNewIssue(issue *models.Issue, mentions []*models.User) {
+	if err := mailer.MailParticipants(issue, issue.Poster, models.ActionCreateIssue, mentions); err != nil {
 		log.Error("MailParticipants: %v", err)
 	}
 }
@@ -69,18 +69,18 @@ func (m *mailNotifier) NotifyIssueChangeStatus(doer *models.User, issue *models.
 		}
 	}
 
-	if err := mailer.MailParticipants(issue, doer, actionType); err != nil {
+	if err := mailer.MailParticipants(issue, doer, actionType, nil); err != nil {
 		log.Error("MailParticipants: %v", err)
 	}
 }
 
-func (m *mailNotifier) NotifyNewPullRequest(pr *models.PullRequest) {
-	if err := mailer.MailParticipants(pr.Issue, pr.Issue.Poster, models.ActionCreatePullRequest); err != nil {
+func (m *mailNotifier) NotifyNewPullRequest(pr *models.PullRequest, mentions []*models.User) {
+	if err := mailer.MailParticipants(pr.Issue, pr.Issue.Poster, models.ActionCreatePullRequest, mentions); err != nil {
 		log.Error("MailParticipants: %v", err)
 	}
 }
 
-func (m *mailNotifier) NotifyPullRequestReview(pr *models.PullRequest, r *models.Review, comment *models.Comment) {
+func (m *mailNotifier) NotifyPullRequestReview(pr *models.PullRequest, r *models.Review, comment *models.Comment, mentions []*models.User) {
 	var act models.ActionType
 	if comment.Type == models.CommentTypeClose {
 		act = models.ActionCloseIssue
@@ -89,11 +89,17 @@ func (m *mailNotifier) NotifyPullRequestReview(pr *models.PullRequest, r *models
 	} else if comment.Type == models.CommentTypeComment {
 		act = models.ActionCommentPull
 	}
-	if err := mailer.MailParticipantsComment(comment, act, pr.Issue); err != nil {
+	if err := mailer.MailParticipantsComment(comment, act, pr.Issue, mentions); err != nil {
 		log.Error("MailParticipantsComment: %v", err)
 	}
 }
 
+func (m *mailNotifier) NotifyPullRequestCodeComment(pr *models.PullRequest, comment *models.Comment, mentions []*models.User) {
+	if err := mailer.MailMentionsComment(pr, comment, mentions); err != nil {
+		log.Error("MailMentionsComment: %v", err)
+	}
+}
+
 func (m *mailNotifier) NotifyIssueChangeAssignee(doer *models.User, issue *models.Issue, assignee *models.User, removed bool, comment *models.Comment) {
 	// mail only sent to added assignees and not self-assignee
 	if !removed && doer.ID != assignee.ID && assignee.EmailNotifications() == models.EmailNotificationsEnabled {
@@ -115,7 +121,7 @@ func (m *mailNotifier) NotifyMergePullRequest(pr *models.PullRequest, doer *mode
 		return
 	}
 	pr.Issue.Content = ""
-	if err := mailer.MailParticipants(pr.Issue, doer, models.ActionMergePullRequest); err != nil {
+	if err := mailer.MailParticipants(pr.Issue, doer, models.ActionMergePullRequest, nil); err != nil {
 		log.Error("MailParticipants: %v", err)
 	}
 }
@@ -143,7 +149,7 @@ func (m *mailNotifier) NotifyPullRequestPushCommits(doer *models.User, pr *model
 	}
 	comment.Content = ""
 
-	m.NotifyCreateIssueComment(doer, comment.Issue.Repo, comment.Issue, comment)
+	m.NotifyCreateIssueComment(doer, comment.Issue.Repo, comment.Issue, comment, nil)
 }
 
 func (m *mailNotifier) NotifyNewRelease(rel *models.Release) {
diff --git a/modules/notification/notification.go b/modules/notification/notification.go
index 21f9dc87a8..7ced57ce2d 100644
--- a/modules/notification/notification.go
+++ b/modules/notification/notification.go
@@ -39,16 +39,16 @@ func NewContext() {
 
 // NotifyCreateIssueComment notifies issue comment related message to notifiers
 func NotifyCreateIssueComment(doer *models.User, repo *models.Repository,
-	issue *models.Issue, comment *models.Comment) {
+	issue *models.Issue, comment *models.Comment, mentions []*models.User) {
 	for _, notifier := range notifiers {
-		notifier.NotifyCreateIssueComment(doer, repo, issue, comment)
+		notifier.NotifyCreateIssueComment(doer, repo, issue, comment, mentions)
 	}
 }
 
 // NotifyNewIssue notifies new issue to notifiers
-func NotifyNewIssue(issue *models.Issue) {
+func NotifyNewIssue(issue *models.Issue, mentions []*models.User) {
 	for _, notifier := range notifiers {
-		notifier.NotifyNewIssue(issue)
+		notifier.NotifyNewIssue(issue, mentions)
 	}
 }
 
@@ -67,9 +67,9 @@ func NotifyMergePullRequest(pr *models.PullRequest, doer *models.User) {
 }
 
 // NotifyNewPullRequest notifies new pull request to notifiers
-func NotifyNewPullRequest(pr *models.PullRequest) {
+func NotifyNewPullRequest(pr *models.PullRequest, mentions []*models.User) {
 	for _, notifier := range notifiers {
-		notifier.NotifyNewPullRequest(pr)
+		notifier.NotifyNewPullRequest(pr, mentions)
 	}
 }
 
@@ -81,9 +81,16 @@ func NotifyPullRequestSynchronized(doer *models.User, pr *models.PullRequest) {
 }
 
 // NotifyPullRequestReview notifies new pull request review
-func NotifyPullRequestReview(pr *models.PullRequest, review *models.Review, comment *models.Comment) {
+func NotifyPullRequestReview(pr *models.PullRequest, review *models.Review, comment *models.Comment, mentions []*models.User) {
 	for _, notifier := range notifiers {
-		notifier.NotifyPullRequestReview(pr, review, comment)
+		notifier.NotifyPullRequestReview(pr, review, comment, mentions)
+	}
+}
+
+// NotifyPullRequestCodeComment notifies new pull request code comment
+func NotifyPullRequestCodeComment(pr *models.PullRequest, comment *models.Comment, mentions []*models.User) {
+	for _, notifier := range notifiers {
+		notifier.NotifyPullRequestCodeComment(pr, comment, mentions)
 	}
 }
 
diff --git a/modules/notification/ui/ui.go b/modules/notification/ui/ui.go
index cadc9720d5..8e510e9cd4 100644
--- a/modules/notification/ui/ui.go
+++ b/modules/notification/ui/ui.go
@@ -51,7 +51,7 @@ func (ns *notificationService) Run() {
 }
 
 func (ns *notificationService) NotifyCreateIssueComment(doer *models.User, repo *models.Repository,
-	issue *models.Issue, comment *models.Comment) {
+	issue *models.Issue, comment *models.Comment, mentions []*models.User) {
 	var opts = issueNotificationOpts{
 		IssueID:              issue.ID,
 		NotificationAuthorID: doer.ID,
@@ -60,13 +60,31 @@ func (ns *notificationService) NotifyCreateIssueComment(doer *models.User, repo
 		opts.CommentID = comment.ID
 	}
 	_ = ns.issueQueue.Push(opts)
+	for _, mention := range mentions {
+		var opts = issueNotificationOpts{
+			IssueID:              issue.ID,
+			NotificationAuthorID: doer.ID,
+			ReceiverID:           mention.ID,
+		}
+		if comment != nil {
+			opts.CommentID = comment.ID
+		}
+		_ = ns.issueQueue.Push(opts)
+	}
 }
 
-func (ns *notificationService) NotifyNewIssue(issue *models.Issue) {
+func (ns *notificationService) NotifyNewIssue(issue *models.Issue, mentions []*models.User) {
 	_ = ns.issueQueue.Push(issueNotificationOpts{
 		IssueID:              issue.ID,
 		NotificationAuthorID: issue.Poster.ID,
 	})
+	for _, mention := range mentions {
+		_ = ns.issueQueue.Push(issueNotificationOpts{
+			IssueID:              issue.ID,
+			NotificationAuthorID: issue.Poster.ID,
+			ReceiverID:           mention.ID,
+		})
+	}
 }
 
 func (ns *notificationService) NotifyIssueChangeStatus(doer *models.User, issue *models.Issue, actionComment *models.Comment, isClosed bool) {
@@ -83,7 +101,7 @@ func (ns *notificationService) NotifyMergePullRequest(pr *models.PullRequest, do
 	})
 }
 
-func (ns *notificationService) NotifyNewPullRequest(pr *models.PullRequest) {
+func (ns *notificationService) NotifyNewPullRequest(pr *models.PullRequest, mentions []*models.User) {
 	if err := pr.LoadIssue(); err != nil {
 		log.Error("Unable to load issue: %d for pr: %d: Error: %v", pr.IssueID, pr.ID, err)
 		return
@@ -92,9 +110,16 @@ func (ns *notificationService) NotifyNewPullRequest(pr *models.PullRequest) {
 		IssueID:              pr.Issue.ID,
 		NotificationAuthorID: pr.Issue.PosterID,
 	})
+	for _, mention := range mentions {
+		_ = ns.issueQueue.Push(issueNotificationOpts{
+			IssueID:              pr.Issue.ID,
+			NotificationAuthorID: pr.Issue.PosterID,
+			ReceiverID:           mention.ID,
+		})
+	}
 }
 
-func (ns *notificationService) NotifyPullRequestReview(pr *models.PullRequest, r *models.Review, c *models.Comment) {
+func (ns *notificationService) NotifyPullRequestReview(pr *models.PullRequest, r *models.Review, c *models.Comment, mentions []*models.User) {
 	var opts = issueNotificationOpts{
 		IssueID:              pr.Issue.ID,
 		NotificationAuthorID: r.Reviewer.ID,
@@ -103,6 +128,28 @@ func (ns *notificationService) NotifyPullRequestReview(pr *models.PullRequest, r
 		opts.CommentID = c.ID
 	}
 	_ = ns.issueQueue.Push(opts)
+	for _, mention := range mentions {
+		var opts = issueNotificationOpts{
+			IssueID:              pr.Issue.ID,
+			NotificationAuthorID: r.Reviewer.ID,
+			ReceiverID:           mention.ID,
+		}
+		if c != nil {
+			opts.CommentID = c.ID
+		}
+		_ = ns.issueQueue.Push(opts)
+	}
+}
+
+func (ns *notificationService) NotifyPullRequestCodeComment(pr *models.PullRequest, c *models.Comment, mentions []*models.User) {
+	for _, mention := range mentions {
+		_ = ns.issueQueue.Push(issueNotificationOpts{
+			IssueID:              pr.Issue.ID,
+			NotificationAuthorID: c.Poster.ID,
+			CommentID:            c.ID,
+			ReceiverID:           mention.ID,
+		})
+	}
 }
 
 func (ns *notificationService) NotifyPullRequestPushCommits(doer *models.User, pr *models.PullRequest, comment *models.Comment) {
diff --git a/modules/notification/webhook/webhook.go b/modules/notification/webhook/webhook.go
index 4b159f6248..a7357a51ca 100644
--- a/modules/notification/webhook/webhook.go
+++ b/modules/notification/webhook/webhook.go
@@ -261,7 +261,7 @@ func (m *webhookNotifier) NotifyIssueChangeStatus(doer *models.User, issue *mode
 	}
 }
 
-func (m *webhookNotifier) NotifyNewIssue(issue *models.Issue) {
+func (m *webhookNotifier) NotifyNewIssue(issue *models.Issue, mentions []*models.User) {
 	if err := issue.LoadRepo(); err != nil {
 		log.Error("issue.LoadRepo: %v", err)
 		return
@@ -283,7 +283,7 @@ func (m *webhookNotifier) NotifyNewIssue(issue *models.Issue) {
 	}
 }
 
-func (m *webhookNotifier) NotifyNewPullRequest(pull *models.PullRequest) {
+func (m *webhookNotifier) NotifyNewPullRequest(pull *models.PullRequest, mentions []*models.User) {
 	if err := pull.LoadIssue(); err != nil {
 		log.Error("pull.LoadIssue: %v", err)
 		return
@@ -399,7 +399,7 @@ func (m *webhookNotifier) NotifyUpdateComment(doer *models.User, c *models.Comme
 }
 
 func (m *webhookNotifier) NotifyCreateIssueComment(doer *models.User, repo *models.Repository,
-	issue *models.Issue, comment *models.Comment) {
+	issue *models.Issue, comment *models.Comment, mentions []*models.User) {
 	mode, _ := models.AccessLevel(doer, repo)
 
 	var err error
@@ -651,7 +651,7 @@ func (m *webhookNotifier) NotifyPullRequestChangeTargetBranch(doer *models.User,
 	}
 }
 
-func (m *webhookNotifier) NotifyPullRequestReview(pr *models.PullRequest, review *models.Review, comment *models.Comment) {
+func (m *webhookNotifier) NotifyPullRequestReview(pr *models.PullRequest, review *models.Review, comment *models.Comment, mentions []*models.User) {
 	var reviewHookType models.HookEventType
 
 	switch review.Type {
diff --git a/services/comments/comments.go b/services/comments/comments.go
index ed479e7110..ad79eec4fb 100644
--- a/services/comments/comments.go
+++ b/services/comments/comments.go
@@ -22,8 +22,11 @@ func CreateIssueComment(doer *models.User, repo *models.Repository, issue *model
 	if err != nil {
 		return nil, err
 	}
-
-	notification.NotifyCreateIssueComment(doer, repo, issue, comment)
+	mentions, err := issue.FindAndUpdateIssueMentions(models.DefaultDBContext(), doer, comment.Content)
+	if err != nil {
+		return nil, err
+	}
+	notification.NotifyCreateIssueComment(doer, repo, issue, comment, mentions)
 
 	return comment, nil
 }
diff --git a/services/issue/issue.go b/services/issue/issue.go
index 0f90a2bcd0..14de0290a1 100644
--- a/services/issue/issue.go
+++ b/services/issue/issue.go
@@ -23,7 +23,12 @@ func NewIssue(repo *models.Repository, issue *models.Issue, labelIDs []int64, uu
 		}
 	}
 
-	notification.NotifyNewIssue(issue)
+	mentions, err := issue.FindAndUpdateIssueMentions(models.DefaultDBContext(), issue.Poster, issue.Content)
+	if err != nil {
+		return err
+	}
+
+	notification.NotifyNewIssue(issue, mentions)
 
 	return nil
 }
diff --git a/services/mailer/mail_comment.go b/services/mailer/mail_comment.go
index 9edbfabd48..2f166720db 100644
--- a/services/mailer/mail_comment.go
+++ b/services/mailer/mail_comment.go
@@ -5,31 +5,20 @@
 package mailer
 
 import (
-	"fmt"
-
 	"code.gitea.io/gitea/models"
 	"code.gitea.io/gitea/modules/log"
-	"code.gitea.io/gitea/modules/references"
 )
 
 // MailParticipantsComment sends new comment emails to repository watchers
 // and mentioned people.
-func MailParticipantsComment(c *models.Comment, opType models.ActionType, issue *models.Issue) error {
-	return mailParticipantsComment(models.DefaultDBContext(), c, opType, issue)
+func MailParticipantsComment(c *models.Comment, opType models.ActionType, issue *models.Issue, mentions []*models.User) error {
+	return mailParticipantsComment(c, opType, issue, mentions)
 }
 
-func mailParticipantsComment(ctx models.DBContext, c *models.Comment, opType models.ActionType, issue *models.Issue) (err error) {
-	rawMentions := references.FindAllMentionsMarkdown(c.Content)
-	userMentions, err := issue.ResolveMentionsByVisibility(ctx, c.Poster, rawMentions)
-	if err != nil {
-		return fmt.Errorf("ResolveMentionsByVisibility [%d]: %v", c.IssueID, err)
-	}
-	if err = models.UpdateIssueMentions(ctx, c.IssueID, userMentions); err != nil {
-		return fmt.Errorf("UpdateIssueMentions [%d]: %v", c.IssueID, err)
-	}
-	mentions := make([]int64, len(userMentions))
-	for i, u := range userMentions {
-		mentions[i] = u.ID
+func mailParticipantsComment(c *models.Comment, opType models.ActionType, issue *models.Issue, mentions []*models.User) (err error) {
+	mentionedIDs := make([]int64, len(mentions))
+	for i, u := range mentions {
+		mentionedIDs[i] = u.ID
 	}
 	if err = mailIssueCommentToParticipants(
 		&mailCommentContext{
@@ -38,8 +27,29 @@ func mailParticipantsComment(ctx models.DBContext, c *models.Comment, opType mod
 			ActionType: opType,
 			Content:    c.Content,
 			Comment:    c,
-		}, mentions); err != nil {
+		}, mentionedIDs); err != nil {
 		log.Error("mailIssueCommentToParticipants: %v", err)
 	}
 	return nil
 }
+
+// MailMentionsComment sends email to users mentioned in a code comment
+func MailMentionsComment(pr *models.PullRequest, c *models.Comment, mentions []*models.User) (err error) {
+	mentionedIDs := make([]int64, len(mentions))
+	for i, u := range mentions {
+		mentionedIDs[i] = u.ID
+	}
+	visited := make(map[int64]bool, len(mentions)+1)
+	visited[c.Poster.ID] = true
+	if err = mailIssueCommentBatch(
+		&mailCommentContext{
+			Issue:      pr.Issue,
+			Doer:       c.Poster,
+			ActionType: models.ActionCommentPull,
+			Content:    c.Content,
+			Comment:    c,
+		}, mentionedIDs, visited, true); err != nil {
+		log.Error("mailIssueCommentBatch: %v", err)
+	}
+	return nil
+}
diff --git a/services/mailer/mail_issue.go b/services/mailer/mail_issue.go
index 30b54eb6cb..ffe2a4e471 100644
--- a/services/mailer/mail_issue.go
+++ b/services/mailer/mail_issue.go
@@ -9,7 +9,6 @@ import (
 
 	"code.gitea.io/gitea/models"
 	"code.gitea.io/gitea/modules/log"
-	"code.gitea.io/gitea/modules/references"
 )
 
 func fallbackMailSubject(issue *models.Issue) string {
@@ -80,6 +79,12 @@ func mailIssueCommentToParticipants(ctx *mailCommentContext, mentions []int64) e
 
 	// Avoid mailing the doer
 	visited[ctx.Doer.ID] = true
+
+	// =========== Mentions ===========
+	if err = mailIssueCommentBatch(ctx, mentions, visited, true); err != nil {
+		return fmt.Errorf("mailIssueCommentBatch() mentions: %v", err)
+	}
+
 	// Avoid mailing explicit unwatched
 	ids, err = models.GetIssueWatchersIDs(ctx.Issue.ID, false)
 	if err != nil {
@@ -93,11 +98,6 @@ func mailIssueCommentToParticipants(ctx *mailCommentContext, mentions []int64) e
 		return fmt.Errorf("mailIssueCommentBatch(): %v", err)
 	}
 
-	// =========== Mentions ===========
-	if err = mailIssueCommentBatch(ctx, mentions, visited, true); err != nil {
-		return fmt.Errorf("mailIssueCommentBatch() mentions: %v", err)
-	}
-
 	return nil
 }
 
@@ -145,22 +145,14 @@ func mailIssueCommentBatch(ctx *mailCommentContext, ids []int64, visited map[int
 
 // MailParticipants sends new issue thread created emails to repository watchers
 // and mentioned people.
-func MailParticipants(issue *models.Issue, doer *models.User, opType models.ActionType) error {
-	return mailParticipants(models.DefaultDBContext(), issue, doer, opType)
+func MailParticipants(issue *models.Issue, doer *models.User, opType models.ActionType, mentions []*models.User) error {
+	return mailParticipants(issue, doer, opType, mentions)
 }
 
-func mailParticipants(ctx models.DBContext, issue *models.Issue, doer *models.User, opType models.ActionType) (err error) {
-	rawMentions := references.FindAllMentionsMarkdown(issue.Content)
-	userMentions, err := issue.ResolveMentionsByVisibility(ctx, doer, rawMentions)
-	if err != nil {
-		return fmt.Errorf("ResolveMentionsByVisibility [%d]: %v", issue.ID, err)
-	}
-	if err = models.UpdateIssueMentions(ctx, issue.ID, userMentions); err != nil {
-		return fmt.Errorf("UpdateIssueMentions [%d]: %v", issue.ID, err)
-	}
-	mentions := make([]int64, len(userMentions))
-	for i, u := range userMentions {
-		mentions[i] = u.ID
+func mailParticipants(issue *models.Issue, doer *models.User, opType models.ActionType, mentions []*models.User) (err error) {
+	mentionedIDs := make([]int64, len(mentions))
+	for i, u := range mentions {
+		mentionedIDs[i] = u.ID
 	}
 	if err = mailIssueCommentToParticipants(
 		&mailCommentContext{
@@ -169,7 +161,7 @@ func mailParticipants(ctx models.DBContext, issue *models.Issue, doer *models.Us
 			ActionType: opType,
 			Content:    issue.Content,
 			Comment:    nil,
-		}, mentions); err != nil {
+		}, mentionedIDs); err != nil {
 		log.Error("mailIssueCommentToParticipants: %v", err)
 	}
 	return nil
diff --git a/services/pull/pull.go b/services/pull/pull.go
index 476c5dad54..35dcbf9604 100644
--- a/services/pull/pull.go
+++ b/services/pull/pull.go
@@ -53,7 +53,12 @@ func NewPullRequest(repo *models.Repository, pull *models.Issue, labelIDs []int6
 		return err
 	}
 
-	notification.NotifyNewPullRequest(pr)
+	mentions, err := pull.FindAndUpdateIssueMentions(models.DefaultDBContext(), pull.Poster, pull.Content)
+	if err != nil {
+		return err
+	}
+
+	notification.NotifyNewPullRequest(pr, mentions)
 
 	// add first push codes comment
 	baseGitRepo, err := git.OpenRepository(pr.BaseRepo.RepoPath())
diff --git a/services/pull/review.go b/services/pull/review.go
index 6781136061..8994a9e78a 100644
--- a/services/pull/review.go
+++ b/services/pull/review.go
@@ -57,7 +57,12 @@ func CreateCodeComment(doer *models.User, gitRepo *git.Repository, issue *models
 			return nil, err
 		}
 
-		notification.NotifyCreateIssueComment(doer, issue.Repo, issue, comment)
+		mentions, err := issue.FindAndUpdateIssueMentions(models.DefaultDBContext(), doer, comment.Content)
+		if err != nil {
+			return nil, err
+		}
+
+		notification.NotifyCreateIssueComment(doer, issue.Repo, issue, comment, mentions)
 
 		return comment, nil
 	}
@@ -226,7 +231,25 @@ func SubmitReview(doer *models.User, gitRepo *git.Repository, issue *models.Issu
 		return nil, nil, err
 	}
 
-	notification.NotifyPullRequestReview(pr, review, comm)
+	ctx := models.DefaultDBContext()
+	mentions, err := issue.FindAndUpdateIssueMentions(ctx, doer, comm.Content)
+	if err != nil {
+		return nil, nil, err
+	}
+
+	notification.NotifyPullRequestReview(pr, review, comm, mentions)
+
+	for _, lines := range review.CodeComments {
+		for _, comments := range lines {
+			for _, codeComment := range comments {
+				mentions, err := issue.FindAndUpdateIssueMentions(ctx, doer, codeComment.Content)
+				if err != nil {
+					return nil, nil, err
+				}
+				notification.NotifyPullRequestCodeComment(pr, codeComment, mentions)
+			}
+		}
+	}
 
 	return review, comm, nil
 }