handle no projects impacted case

Author: motatoes

backend/controllers/github.go

@@ -444,6 +444,10 @@ func handlePullRequestEvent(gh utils.GithubClientProvider, payload *github.PullR
 		utils.InitCommentReporter(ghService, prNumber, fmt.Sprintf(":x: Failed to comment initial status for jobs: %v", err))
 		return fmt.Errorf("failed to comment initial status for jobs")
 	}
+	
+	if len(jobsForImpactedProjects) == 0 {
+		return nil
+	}
 
 	err = utils.SetPRStatusForJobs(ghService, prNumber, jobsForImpactedProjects)
 	if err != nil {
@@ -573,7 +577,7 @@ func handleIssueCommentEvent(gh utils.GithubClientProvider, payload *github.Issu
 	issueNumber := *payload.Issue.Number
 
 	if *payload.Action != "created" {
-		log.Printf("comment is not created, ignoring")
+		log.Printf("comment is not of type 'created', ignoring")
 		return nil
 	}
 
@@ -610,7 +614,6 @@ func handleIssueCommentEvent(gh utils.GithubClientProvider, payload *github.Issu
 	}
 
 	jobs, _, err := dg_github.ConvertGithubIssueCommentEventToJobs(payload, impactedProjects, requestedProject, config.Workflows, prBranchName)
-
 	if err != nil {
 		log.Printf("Error converting event to jobs: %v", err)
 		utils.InitCommentReporter(ghService, issueNumber, fmt.Sprintf(":x: Error converting event to jobs: %v", err))
@@ -625,6 +628,10 @@ func handleIssueCommentEvent(gh utils.GithubClientProvider, payload *github.Issu
 		return fmt.Errorf("failed to comment initial status for jobs")
 	}
 
+	if len(jobs) == 0 {
+		return nil
+	}
+
 	err = utils.SetPRStatusForJobs(ghService, issueNumber, jobs)
 	if err != nil {
 		log.Printf("error setting status for PR: %v", err)

backend/utils/pr_comment.go

@@ -25,6 +25,27 @@ func InitCommentReporter(prService *github2.GithubService, prNumber int, comment
 }
 
 func ReportInitialJobsStatus(cr *CommentReporter, jobs []orchestrator.Job) error {
+	prNumber := cr.PrNumber
+	prService := cr.PrService
+	commentId := cr.CommentId
+	message := ""
+	if len(jobs) == 0 {
+		message = message + ":construction_worker: The following projects are impacted\n\n"
+		for _, job := range jobs {
+			message = message + fmt.Sprintf(""+
+				"<!-- PROJECTHOLDER %v -->\n"+
+				":clock11: **%v**: pending...\n"+
+				"<!-- PROJECTHOLDEREND %v -->\n"+
+				"", job.ProjectName, job.ProjectName, job.ProjectName)
+		}
+	} else {
+		message = message + ":construction_worker: No projects impacted"
+	}
+	err := prService.EditComment(prNumber, commentId, message)
+	return err
+}
+
+func ReportNoProjectsImpacted(cr *CommentReporter, jobs []orchestrator.Job) error {
 	prNumber := cr.PrNumber
 	prService := cr.PrService
 	commentId := cr.CommentId