Add LGTM timestamp checking.

contrib/submit-queue/github/github.go

@@ -86,6 +86,28 @@ type FilterConfig struct {
 	RequiredStatusContexts []string
 }
 
+func validateLGTMAfterPush(client *github.Client, user, project string, pr *github.PullRequest) (bool, error) {
+	var lgtmTime *time.Time
+	events, _, err := client.Issues.ListIssueEvents(user, project, *pr.Number, &github.ListOptions{})
+	if err != nil {
+		glog.Errorf("Error getting events for issue: %v", err)
+		return false, err
+	}
+	for ix := range events {
+		event := &events[ix]
+		if *event.Event == "labeled" && *event.Label.Name == "lgtm" {
+			*lgtmTime = *event.CreatedAt
+		}
+	}
+	if lgtmTime == nil {
+		return false, fmt.Errorf("Couldn't find time for LGTM label, this shouldn't happen, skipping PR: %d", *pr.Number)
+	}
+	if pr.Head == nil || pr.Head.Repo == nil || pr.Head.Repo.PushedAt == nil {
+		return false, fmt.Errorf("Couldn't find push time for PR, this shouldn't happen, skipping PR: %d", *pr.Number)
+	}
+	return pr.Head.Repo.PushedAt.Before(*lgtmTime), nil
+}
+
 // For each PR in the project that matches:
 //   * pr.Number > minPRNumber
 //   * is mergeable
@@ -124,6 +146,7 @@ func ForEachCandidatePRDo(client *github.Client, user, project string, fn PRFunc
 			glog.Errorf("Failed to get issue for PR: %v", err)
 			continue
 		}
+
 		glog.V(8).Infof("%v", issue.Labels)
 		if !hasLabels(issue.Labels, []string{"lgtm", "cla: yes"}) {
 			continue
@@ -133,6 +156,21 @@ func ForEachCandidatePRDo(client *github.Client, user, project string, fn PRFunc
 			continue
 		}
 
+		if ok, err := validateLGTMAfterPush(client, user, project, pr); err != nil {
+			glog.Errorf("Error validating LGTM: %v, Skipping: %d", err, *pr.Number)
+			continue
+		} else if !ok {
+			glog.Errorf("PR pushed after LGTM, attempting to remove LGTM and skipping")
+			staleLGTMBody := "LGTM was before last commit, removing LGTM"
+			if _, _, err := client.Issues.CreateComment(user, project, *pr.Number, &github.IssueComment{Body: &staleLGTMBody}); err != nil {
+				glog.Warningf("Failed to create remove label comment: %v", err)
+			}
+			if _, err := client.Issues.RemoveLabelForIssue(user, project, *pr.Number, "lgtm"); err != nil {
+				glog.Warningf("Failed to remove 'lgtm' label for stale lgtm on %d", *pr.Number)
+			}
+			continue
+		}
+
 		// This is annoying, github appears to only temporarily cache mergeability, if it is nil, wait
 		// for an async refresh and retry.
 		if pr.Mergeable == nil {