From 1c47715ed16c43bc8eb8baeb871bf6eaa22e51be Mon Sep 17 00:00:00 2001
From: Tim Abbott <tabbott@zulip.com>
Date: Mon, 15 Jan 2024 16:58:34 -0800
Subject: [PATCH] tools: Add a tool for backporting PRs.

(cherry picked from commit ef3f990324644aeed8748ae90f05f3a528c06b6d)
---
 tools/backport-pull-request | 35 +++++++++++++++++++++++++++++++++++
 1 file changed, 35 insertions(+)
 create mode 100755 tools/backport-pull-request

diff --git a/tools/backport-pull-request b/tools/backport-pull-request
new file mode 100755
index 0000000000..73aee49b1f
--- /dev/null
+++ b/tools/backport-pull-request
@@ -0,0 +1,35 @@
+#!/usr/bin/env bash
+set -e
+
+usage() {
+    cat >&2 <<EOF
+usage: $0 PULL_REQUEST_ID COMMIT_COUNT [REMOTE]
+
+Fetch the given GitHub pull request branch and backport it to
+the current branch using 'git cherry-pick -x'.
+
+Typical usage is:
+  git fetch upstream
+  git checkout -b 8.x upstream/8.x
+  $0 FIRST_PR_ID FIRST_PR_COMMIT_COUNT
+  $0 SECOND_PR_ID SECOND_PR_COMMIT_COUNT
+  git push origin +HEAD:backport-changes
+EOF
+    exit 1
+}
+
+remote_default="$(git config zulip.zulipRemote || echo upstream)"
+
+request_id="$1"
+commit_count="$2"
+
+if [ -z "$request_id" ] || [ -z "$commit_count" ]; then
+    usage
+fi
+
+remote=${3:-"$remote_default"}
+
+set -x
+
+git fetch "$remote" "pull/$request_id/head"
+git cherry-pick -x FETCH_HEAD~"$commit_count"..FETCH_HEAD