Add note about retriggering

Fixes #2127

packit_service/constants.py

@@ -52,6 +52,12 @@
     "You can retrigger the {job} by adding a comment (`{packit_comment_command_prefix} {command}`) "
     "into this {place}."
 )
+
+MSG_RETRIGGER_DISTGIT = (
+    "You can retrigger the {job} by adding a comment (`{packit_comment_command_prefix} {command}`) "
+    "into any open open pull request in dist-git."
+)
+
 COPR_CHROOT_CHANGE_MSG = (
     "Settings of a Copr project {owner}/{project} need to be updated, "
     "but Packit can't do that when there are previous builds still in progress.\n"

packit_service/worker/handlers/distgit.py

@@ -32,6 +32,7 @@
     MSG_GET_IN_TOUCH,
     MSG_DOWNSTREAM_JOB_ERROR_HEADER,
     DEFAULT_RETRY_BACKOFF,
+    MSG_RETRIGGER_DISTGIT,
     RETRY_LIMIT_RELEASE_ARCHIVE_DOWNLOAD_ERROR,
 )
 from packit_service.models import (
@@ -491,6 +492,14 @@ def run(self) -> TaskResults:
                 dist_git_url=self.packit_api.dg.local_project.git_url,
             )
             body_msg += f"{branch_errors}\n\n"
+
+            if self.task_name == TaskName.pull_from_upstream:
+                body_msg += MSG_RETRIGGER_DISTGIT.format(
+                    job="pull_from_upstream",
+                    packit_comment_command_prefix=self.service_config.comment_command_prefix,
+                    command="pull-from-upstream",
+                )
+
             self._report_errors_for_each_branch(body_msg)
             sync_release_run_model.set_status(status=SyncReleaseStatus.error)
             return TaskResults(