services: Use proper Message-IDs for release mails

When sending notification emails about a release, use a properly
formatted, RFC-compliant message id, rather than the release's HTML URL
wrapped in angle brackets (which would not be compliant).

Fixes #3105.

Signed-off-by: Gergely Nagy <forgejo@gergo.csillger.hu>

services/mailer/mail.go

@@ -389,6 +389,10 @@ func createReference(issue *issues_model.Issue, comment *issues_model.Comment, a
 	return fmt.Sprintf("<%s/%s/%d%s@%s>", issue.Repo.FullName(), path, issue.Index, extra, setting.Domain)
 }
 
+func createMessageIDForRelease(rel *repo_model.Release) string {
+	return fmt.Sprintf("<%s/releases/%d@%s>", rel.Repo.FullName(), rel.ID, setting.Domain)
+}
+
 func generateAdditionalHeaders(ctx *mailCommentContext, reason string, recipient *user_model.User) map[string]string {
 	repo := ctx.Issue.Repo
 

services/mailer/mail_release.go

@@ -86,11 +86,11 @@ func mailNewRelease(ctx context.Context, lang string, tos []string, rel *repo_mo
 
 	msgs := make([]*Message, 0, len(tos))
 	publisherName := rel.Publisher.DisplayName()
-	relURL := "<" + rel.HTMLURL() + ">"
+	msgID := createMessageIDForRelease(rel)
 	for _, to := range tos {
 		msg := NewMessageFrom(to, publisherName, setting.MailService.FromEmail, subject, mailBody.String())
 		msg.Info = subject
-		msg.SetHeader("Message-ID", relURL)
+		msg.SetHeader("Message-ID", msgID)
 		msgs = append(msgs, msg)
 	}
 

services/mailer/mailer_test.go

@@ -7,6 +7,7 @@ import (
 	"testing"
 	"time"
 
+	repo_model "code.gitea.io/gitea/models/repo"
 	"code.gitea.io/gitea/modules/setting"
 
 	"github.com/stretchr/testify/assert"
@@ -36,3 +37,17 @@ func TestGenerateMessageID(t *testing.T) {
 	gm = m.ToMessage()
 	assert.Equal(t, "<msg-d@domain.com>", gm.GetHeader("Message-ID")[0])
 }
+
+func TestGenerateMessageIDForRelease(t *testing.T) {
+	setting.Domain = "localhost"
+
+	rel := repo_model.Release{
+		ID: 42,
+		Repo: &repo_model.Repository{
+			OwnerName: "test",
+			Name:      "tag-test",
+		},
+	}
+	m := createMessageIDForRelease(&rel)
+	assert.Equal(t, "<test/tag-test/releases/42@localhost>", m)
+}