Only check for conflicts/merging if the PR has not been merged in the interim

models/pull.go

@@ -514,10 +514,20 @@ func (pr *PullRequest) SetMerged() (err error) {
 		return err
 	}
 
+	if count, err := sess.Where("id = ? AND has_merged != ?", pr.ID, true).Count(new(PullRequest)); err != nil {
+		return err
+	} else if count < 1 {
+		return nil
+	}
+
 	if err = pr.loadIssue(sess); err != nil {
 		return err
 	}
 
+	if pr.Issue.IsClosed {
+		return nil
+	}
+
 	if err = pr.Issue.loadRepo(sess); err != nil {
 		return err
 	}
@@ -707,6 +717,12 @@ func (pr *PullRequest) UpdateCols(cols ...string) error {
 	return err
 }
 
+// UpdateColsIfNotMerged updates specific fields of a pull request if it has not been merged
+func (pr *PullRequest) UpdateColsIfNotMerged(cols ...string) error {
+	_, err := x.ID(pr.ID).Where("has_merged = ?", false).Cols(cols...).Update(pr)
+	return err
+}
+
 // IsWorkInProgress determine if the Pull Request is a Work In Progress by its title
 func (pr *PullRequest) IsWorkInProgress() bool {
 	if err := pr.LoadIssue(); err != nil {

services/pull/check.go

@@ -32,7 +32,7 @@ func AddToTaskQueue(pr *models.PullRequest) {
 	go func() {
 		err := prQueue.PushFunc(strconv.FormatInt(pr.ID, 10), func() error {
 			pr.Status = models.PullRequestStatusChecking
-			err := pr.UpdateCols("status")
+			err := pr.UpdateColsIfNotMerged("status")
 			if err != nil {
 				log.Error("AddToTaskQueue.UpdateCols[%d].(add to queue): %v", pr.ID, err)
 			} else {
@@ -205,7 +205,7 @@ func handle(data ...queue.Data) {
 		if err != nil {
 			log.Error("GetPullRequestByID[%s]: %v", prID, err)
 			continue
-		} else if pr.Status != models.PullRequestStatusChecking {
+		} else if pr.HasMerged {
 			continue
 		} else if manuallyMerged(pr) {
 			continue