Improve the `issue_comment` workflow trigger event (#29277)

Fix #29175
Replace #29207

This PR makes some improvements to the `issue_comment` workflow trigger
event.

1. Fix the bug that pull requests cannot trigger `issue_comment`
workflows
2. Previously the `issue_comment` event only supported the `created`
activity type. This PR adds support for the missing `edited` and
`deleted` activity types.
3. Some events (including `issue_comment`, `issues`, etc. ) only trigger
workflows that belong to the workflow file on the default branch. This
PR introduces the `IsDefaultBranchWorkflow` function to check for these
events.

2 files changed, 80 insertions, 27 deletions

diff --git a/services/actions/notifier.go b/services/actions/notifier.go
index 77848a3f58..e144484dab 100644
--- a/services/actions/notifier.go
+++ b/services/actions/notifier.go
@@ -224,37 +224,88 @@ func (n *actionsNotifier) CreateIssueComment(ctx context.Context, doer *user_mod
 ) {
 	ctx = withMethod(ctx, "CreateIssueComment")
 
-	permission, _ := access_model.GetUserRepoPermission(ctx, repo, doer)
-
 	if issue.IsPull {
-		if err := issue.LoadPullRequest(ctx); err != nil {
+		notifyIssueCommentChange(ctx, doer, comment, "", webhook_module.HookEventPullRequestComment, api.HookIssueCommentCreated)
+		return
+	}
+	notifyIssueCommentChange(ctx, doer, comment, "", webhook_module.HookEventIssueComment, api.HookIssueCommentCreated)
+}
+
+func (n *actionsNotifier) UpdateComment(ctx context.Context, doer *user_model.User, c *issues_model.Comment, oldContent string) {
+	ctx = withMethod(ctx, "UpdateComment")
+
+	if err := c.LoadIssue(ctx); err != nil {
+		log.Error("LoadIssue: %v", err)
+		return
+	}
+
+	if c.Issue.IsPull {
+		notifyIssueCommentChange(ctx, doer, c, oldContent, webhook_module.HookEventPullRequestComment, api.HookIssueCommentEdited)
+		return
+	}
+	notifyIssueCommentChange(ctx, doer, c, oldContent, webhook_module.HookEventIssueComment, api.HookIssueCommentEdited)
+}
+
+func (n *actionsNotifier) DeleteComment(ctx context.Context, doer *user_model.User, comment *issues_model.Comment) {
+	ctx = withMethod(ctx, "DeleteComment")
+
+	if err := comment.LoadIssue(ctx); err != nil {
+		log.Error("LoadIssue: %v", err)
+		return
+	}
+
+	if comment.Issue.IsPull {
+		notifyIssueCommentChange(ctx, doer, comment, "", webhook_module.HookEventPullRequestComment, api.HookIssueCommentDeleted)
+		return
+	}
+	notifyIssueCommentChange(ctx, doer, comment, "", webhook_module.HookEventIssueComment, api.HookIssueCommentDeleted)
+}
+
+func notifyIssueCommentChange(ctx context.Context, doer *user_model.User, comment *issues_model.Comment, oldContent string, event webhook_module.HookEventType, action api.HookIssueCommentAction) {
+	if err := comment.LoadIssue(ctx); err != nil {
+		log.Error("LoadIssue: %v", err)
+		return
+	}
+	if err := comment.Issue.LoadAttributes(ctx); err != nil {
+		log.Error("LoadAttributes: %v", err)
+		return
+	}
+
+	permission, _ := access_model.GetUserRepoPermission(ctx, comment.Issue.Repo, doer)
+
+	payload := &api.IssueCommentPayload{
+		Action:     action,
+		Issue:      convert.ToAPIIssue(ctx, comment.Issue),
+		Comment:    convert.ToAPIComment(ctx, comment.Issue.Repo, comment),
+		Repository: convert.ToRepo(ctx, comment.Issue.Repo, permission),
+		Sender:     convert.ToUser(ctx, doer, nil),
+		IsPull:     comment.Issue.IsPull,
+	}
+
+	if action == api.HookIssueCommentEdited {
+		payload.Changes = &api.ChangesPayload{
+			Body: &api.ChangesFromPayload{
+				From: oldContent,
+			},
+		}
+	}
+
+	if comment.Issue.IsPull {
+		if err := comment.Issue.LoadPullRequest(ctx); err != nil {
 			log.Error("LoadPullRequest: %v", err)
 			return
 		}
-		newNotifyInputFromIssue(issue, webhook_module.HookEventPullRequestComment).
+		newNotifyInputFromIssue(comment.Issue, event).
 			WithDoer(doer).
-			WithPayload(&api.IssueCommentPayload{
-				Action:     api.HookIssueCommentCreated,
-				Issue:      convert.ToAPIIssue(ctx, issue),
-				Comment:    convert.ToAPIComment(ctx, repo, comment),
-				Repository: convert.ToRepo(ctx, repo, permission),
-				Sender:     convert.ToUser(ctx, doer, nil),
-				IsPull:     true,
-			}).
-			WithPullRequest(issue.PullRequest).
+			WithPayload(payload).
+			WithPullRequest(comment.Issue.PullRequest).
 			Notify(ctx)
 		return
 	}
-	newNotifyInputFromIssue(issue, webhook_module.HookEventIssueComment).
+
+	newNotifyInputFromIssue(comment.Issue, event).
 		WithDoer(doer).
-		WithPayload(&api.IssueCommentPayload{
-			Action:     api.HookIssueCommentCreated,
-			Issue:      convert.ToAPIIssue(ctx, issue),
-			Comment:    convert.ToAPIComment(ctx, repo, comment),
-			Repository: convert.ToRepo(ctx, repo, permission),
-			Sender:     convert.ToUser(ctx, doer, nil),
-			IsPull:     false,
-		}).
+		WithPayload(payload).
 		Notify(ctx)
 }
 
@@ -496,7 +547,6 @@ func (n *actionsNotifier) DeleteRef(ctx context.Context, pusher *user_model.User
 	apiRepo := convert.ToRepo(ctx, repo, access_model.Permission{AccessMode: perm_model.AccessModeNone})
 
 	newNotifyInput(repo, pusher, webhook_module.HookEventDelete).
-		WithRef(refFullName.ShortName()). // FIXME: should we use a full ref name
 		WithPayload(&api.DeletePayload{
 			Ref:        refFullName.ShortName(),
 			RefType:    refFullName.RefType(),
diff --git a/services/actions/notifier_helper.go b/services/actions/notifier_helper.go
index 8852f23c5f..c20335af6f 100644
--- a/services/actions/notifier_helper.go
+++ b/services/actions/notifier_helper.go
@@ -136,12 +136,15 @@ func notify(ctx context.Context, input *notifyInput) error {
 	defer gitRepo.Close()
 
 	ref := input.Ref
-	if input.Event == webhook_module.HookEventDelete {
-		// The event is deleting a reference, so it will fail to get the commit for a deleted reference.
-		// Set ref to empty string to fall back to the default branch.
-		ref = ""
+	if ref != input.Repo.DefaultBranch && actions_module.IsDefaultBranchWorkflow(input.Event) {
+		if ref != "" {
+			log.Warn("Event %q should only trigger workflows on the default branch, but its ref is %q. Will fall back to the default branch",
+				input.Event, ref)
+		}
+		ref = input.Repo.DefaultBranch
 	}
 	if ref == "" {
+		log.Warn("Ref of event %q is empty, will fall back to the default branch", input.Event)
 		ref = input.Repo.DefaultBranch
 	}