Auto merge PR that has label AutoMerge. Can be run regularly with cron job or similar

auto-merge-pr.sh

#!/bin/bash

set -euo pipefail

# Optional: Set to true to update the PR with the base branch before merging
UPDATE_BEFORE_MERGE=true

# Get current ISO timestamp minus 2 hours
TWO_HOURS_AGO=$(date -u -d '2 hours ago' +"%Y-%m-%dT%H:%M:%SZ")

# Function to update the PR branch with base (main)
update_branch() {
  local pr="$1"
  echo "🔄 Updating PR #$pr with base branch..."
  gh pr update-branch "$pr" || echo "⚠️ Could not update PR #$pr"
}

# Function to attempt merging a PR
try_merge() {
  local pr="$1"
  echo "🚀 Trying to merge PR #$pr..."
  if gh pr merge "$pr" --squash ; then
    echo "✅ Merged PR #$pr"
  else
    echo "❌ Merge failed or not ready for PR #$pr"
  fi
}

# If no PRs passed, discover eligible ones
if [ "$#" -eq 0 ]; then
  echo "🔍 Discovering mergeable PRs with label 'AutoMerge' updated in the last 2 hours..."

  mapfile -t PR_LIST < <(
    gh pr list --state open --label AutoMerge --json number,isDraft,labels,mergeable,updatedAt |
      jq --arg since "$TWO_HOURS_AGO" '
        [ .[] | select(
          .isDraft == false and
          .mergeable == "MERGEABLE" and
          (.labels[].name? | contains("AutoMerge")) and
          (.updatedAt > $since)
        ) | .number ] | .[]'
  )
else
  PR_LIST=("$@")
fi

if [ ${#PR_LIST[@]} -eq 0 ]; then
  echo "ℹ️ No eligible PRs to merge."
  exit 0
fi

# Merge each eligible PR
for pr in "${PR_LIST[@]}"; do
  echo "🔄 Processing PR #$pr..."
  $UPDATE_BEFORE_MERGE && update_branch "$pr"
  try_merge "$pr"
done

echo "✅ Done."