From fce05d04289d6cb7019b2a76763543dfce67189a Mon Sep 17 00:00:00 2001
From: Danny Kopping <danny@coder.com>
Date: Thu, 2 Apr 2026 15:19:06 +0200
Subject: [PATCH] feat: add backport PR script (#23973)

_Disclaimer: created using Claude Opus 4.6._

```
# Examples:
#   ./scripts/backport-pr.sh 2.30 23969
#   ./scripts/backport-pr.sh --dry-run 2.30 23969
```

Here's one I created: https://github.com/coder/coder/pull/23972

Signed-off-by: Danny Kopping <danny@coder.com>
---
 scripts/backport-pr.sh | 136 +++++++++++++++++++++++++++++++++++++++++
 1 file changed, 136 insertions(+)
 create mode 100755 scripts/backport-pr.sh

diff --git a/scripts/backport-pr.sh b/scripts/backport-pr.sh
new file mode 100755
index 0000000000..da370220c9
--- /dev/null
+++ b/scripts/backport-pr.sh
@@ -0,0 +1,136 @@
+#!/usr/bin/env bash
+# Usage: ./scripts/backport-pr.sh [--dry-run] <release-version> <pr-number>
+#
+# Backports a merged PR to a release branch by cherry-picking its merge commit
+# and opening a new PR targeting the release branch.
+#
+# Examples:
+#   ./scripts/backport-pr.sh 2.30 23969
+#   ./scripts/backport-pr.sh --dry-run 2.30 23969
+
+set -euo pipefail
+# shellcheck source=scripts/lib.sh
+source "$(dirname "${BASH_SOURCE[0]}")/lib.sh"
+cdroot
+
+dry_run=0
+
+# Parse flags.
+while [[ $# -gt 0 ]]; do
+	case "$1" in
+	--dry-run | -n)
+		dry_run=1
+		shift
+		;;
+	-*)
+		error "Unknown flag: $1"
+		;;
+	*)
+		break
+		;;
+	esac
+done
+
+if [[ $# -lt 2 ]]; then
+	echo "Usage: $0 [--dry-run] <release-version> <pr-number>" >&2
+	echo "  e.g. $0 2.30 23969" >&2
+	exit 1
+fi
+
+release_version="$1"
+pr_number="$2"
+release_branch="release/${release_version}"
+
+dependencies gh jq git
+
+# Authenticate with GitHub.
+gh_auth
+
+# Validate that the PR exists and is merged.
+log "Fetching PR #${pr_number}..."
+pr_json=$(gh pr view "$pr_number" --json mergeCommit,title,number,state,headRefName,url)
+
+pr_state=$(echo "$pr_json" | jq -r '.state')
+if [[ "$pr_state" != "MERGED" ]]; then
+	error "PR #${pr_number} is not merged (state: ${pr_state})."
+fi
+
+merge_commit=$(echo "$pr_json" | jq -r '.mergeCommit.oid')
+pr_title=$(echo "$pr_json" | jq -r '.title')
+pr_url=$(echo "$pr_json" | jq -r '.url')
+
+if [[ -z "$merge_commit" || "$merge_commit" == "null" ]]; then
+	error "Could not determine merge commit for PR #${pr_number}."
+fi
+
+log "PR:            #${pr_number} - ${pr_title}"
+log "Merge commit:  ${merge_commit}"
+log "Release branch: ${release_branch}"
+
+# Make sure we have the latest refs.
+maybedryrun "$dry_run" git fetch origin
+
+# Validate the release branch exists on the remote.
+if ! git rev-parse "origin/${release_branch}" >/dev/null 2>&1; then
+	error "Release branch '${release_branch}' does not exist on origin."
+fi
+
+backport_branch="backport/${pr_number}-to-${release_version}"
+log "Backport branch: ${backport_branch}"
+
+if [[ "$dry_run" == 1 ]]; then
+	log ""
+	log "DRYRUN: Would cherry-pick ${merge_commit} onto ${release_branch} via branch ${backport_branch}"
+	log "DRYRUN: Would create PR targeting ${release_branch}"
+	exit 0
+fi
+
+# Check for uncommitted changes that would block checkout.
+if ! git diff-index --quiet HEAD --; then
+	error "You have uncommitted changes. Please commit or stash them first."
+fi
+
+# Create the backport branch from the release branch.
+log "Creating branch ${backport_branch} from origin/${release_branch}..."
+git checkout -b "$backport_branch" "origin/${release_branch}"
+
+# Cherry-pick the merge commit.
+log "Cherry-picking ${merge_commit}..."
+if ! git cherry-pick "$merge_commit"; then
+	log ""
+	log "Cherry-pick failed due to conflicts."
+	log "Resolve the conflicts, then run:"
+	log "  git cherry-pick --continue"
+	log "  git push origin ${backport_branch}"
+	log "  gh pr create --base ${release_branch} --head ${backport_branch} --title \"chore: backport #${pr_number} to ${release_version}\" --body \"Backport of ${pr_url}\""
+	log ""
+	log "Or abort with: git cherry-pick --abort && git checkout - && git branch -D ${backport_branch}"
+	exit 1
+fi
+
+# Push the backport branch.
+log "Pushing ${backport_branch}..."
+git push origin "$backport_branch"
+
+# Create the PR.
+log "Creating PR..."
+backport_pr_url=$(gh pr create \
+	--draft \
+	--label "cherry-pick/v${release_version}" \
+	--base "$release_branch" \
+	--head "$backport_branch" \
+	--title "chore: backport #${pr_number} to ${release_version}" \
+	--body "$(
+		cat <<EOF
+Backport of ${pr_url}
+
+Original PR: #${pr_number} — ${pr_title}
+Merge commit: ${merge_commit}
+EOF
+	)")
+
+log ""
+log "Backport PR created: ${backport_pr_url}"
+
+# Return to previous branch.
+git checkout -