4 files changed, 43 insertions, 0 deletions
diff --git a/modules/notification/base/notifier.go b/modules/notification/base/notifier.go
index 934ee80aa7..48846b3446 100644
--- a/modules/notification/base/notifier.go
+++ b/modules/notification/base/notifier.go
@@ -34,6 +34,7 @@ type Notifier interface {
 	NotifyMergePullRequest(*models.PullRequest, *models.User, *git.Repository)
 	NotifyPullRequestSynchronized(doer *models.User, pr *models.PullRequest)
 	NotifyPullRequestReview(*models.PullRequest, *models.Review, *models.Comment)
+	NotifyPullRequestChangeTargetBranch(doer *models.User, pr *models.PullRequest, oldBranch string)
 
 	NotifyCreateIssueComment(*models.User, *models.Repository,
 		*models.Issue, *models.Comment)
diff --git a/modules/notification/base/null.go b/modules/notification/base/null.go
index a04d0e8caa..bea4e55277 100644
--- a/modules/notification/base/null.go
+++ b/modules/notification/base/null.go
@@ -50,6 +50,10 @@ func (*NullNotifier) NotifyMergePullRequest(pr *models.PullRequest, doer *models
 func (*NullNotifier) NotifyPullRequestSynchronized(doer *models.User, pr *models.PullRequest) {
 }
 
+// NotifyPullRequestChangeTargetBranch places a place holder function
+func (*NullNotifier) NotifyPullRequestChangeTargetBranch(doer *models.User, pr *models.PullRequest, oldBranch string) {
+}
+
 // NotifyUpdateComment places a place holder function
 func (*NullNotifier) NotifyUpdateComment(doer *models.User, c *models.Comment, oldContent string) {
 }
diff --git a/modules/notification/notification.go b/modules/notification/notification.go
index ab671fa291..f567552df5 100644
--- a/modules/notification/notification.go
+++ b/modules/notification/notification.go
@@ -87,6 +87,13 @@ func NotifyPullRequestReview(pr *models.PullRequest, review *models.Review, comm
 	}
 }
 
+// NotifyPullRequestChangeTargetBranch notifies when a pull request's target branch was changed
+func NotifyPullRequestChangeTargetBranch(doer *models.User, pr *models.PullRequest, oldBranch string) {
+	for _, notifier := range notifiers {
+		notifier.NotifyPullRequestChangeTargetBranch(doer, pr, oldBranch)
+	}
+}
+
 // NotifyUpdateComment notifies update comment to notifiers
 func NotifyUpdateComment(doer *models.User, c *models.Comment, oldContent string) {
 	for _, notifier := range notifiers {
diff --git a/modules/notification/webhook/webhook.go b/modules/notification/webhook/webhook.go
index ee91a29f02..e0801445d8 100644
--- a/modules/notification/webhook/webhook.go
+++ b/modules/notification/webhook/webhook.go
@@ -559,6 +559,37 @@ func (*webhookNotifier) NotifyMergePullRequest(pr *models.PullRequest, doer *mod
 	}
 }
 
+func (m *webhookNotifier) NotifyPullRequestChangeTargetBranch(doer *models.User, pr *models.PullRequest, oldBranch string) {
+	issue := pr.Issue
+	if !issue.IsPull {
+		return
+	}
+	var err error
+
+	if err = issue.LoadPullRequest(); err != nil {
+		log.Error("LoadPullRequest failed: %v", err)
+		return
+	}
+	issue.PullRequest.Issue = issue
+	mode, _ := models.AccessLevel(issue.Poster, issue.Repo)
+	err = webhook_module.PrepareWebhooks(issue.Repo, models.HookEventPullRequest, &api.PullRequestPayload{
+		Action: api.HookIssueEdited,
+		Index:  issue.Index,
+		Changes: &api.ChangesPayload{
+			Ref: &api.ChangesFromPayload{
+				From: oldBranch,
+			},
+		},
+		PullRequest: issue.PullRequest.APIFormat(),
+		Repository:  issue.Repo.APIFormat(mode),
+		Sender:      doer.APIFormat(),
+	})
+
+	if err != nil {
+		log.Error("PrepareWebhooks [is_pull: %v]: %v", issue.IsPull, err)
+	}
+}
+
 func (m *webhookNotifier) NotifyPullRequestReview(pr *models.PullRequest, review *models.Review, comment *models.Comment) {
 	var reviewHookType models.HookEventType