Bash script to generate a markdown link for the Lotus CHANGELOG for a PR

lotus-pr.sh

#!/bin/bash

## lotus-pr.sh
# This script checks if the current branch has an open pull request on the Filecoin Lotus repository.
# If a PR is found, it will output the PR number and a markdown link for CHANGELOG.md.
# If no PR is found, it will predict the next PR number based on the latest PR in the repository.
# The script requires the 'jq' command-line JSON processor and 'xclip' or 'pbcopy' for copying to clipboard.

REPO="filecoin-project/lotus"
GITHUB_API="https://api.github.com"

if [ -n "$GITHUB_TOKEN" ]; then
  AUTH_HEADER="Authorization: token $GITHUB_TOKEN"
else
  echo "Warning: No GITHUB_TOKEN found. API rate limits will be more restrictive."
  AUTH_HEADER=""
fi

CURRENT_BRANCH=$(git rev-parse --abbrev-ref HEAD)

github_api_get() {
  local endpoint="$1"
  local url="${GITHUB_API}/${endpoint}"

  if [ -n "$AUTH_HEADER" ]; then
    curl -s -H "$AUTH_HEADER" "$url"
  else
    curl -s "$url"
  fi
}

# Check if current branch has an open PR
check_existing_pr() {
  echo "Checking if branch '$CURRENT_BRANCH' has an open pull request..."

  pr_data=$(github_api_get "repos/${REPO}/pulls?head=${REPO%/*}:${CURRENT_BRANCH}&state=open")

  # Check if the response contains any PRs
  if [ "$(echo "$pr_data" | jq 'length')" -gt 0 ]; then
    pr_number=$(echo "$pr_data" | jq '.[0].number')
    echo "Found existing PR #$pr_number for branch '$CURRENT_BRANCH'"
    format_pr_link "$pr_number"
    return 0
  else
    echo "No open PR found for branch '$CURRENT_BRANCH'"
    return 1
  fi
}

# Get the highest number from issues (which includes PRs) and increment it
predict_next_number() {
  echo "Predicting next number for PR or issue..."
  
  # Get the latest issue/PR (they share the same number space)
  latest=$(github_api_get "repos/${REPO}/issues?state=all&sort=created&direction=desc&per_page=1")
  
  if [ -z "$latest" ] || [ "$latest" = "[]" ]; then
    echo "Error: Could not fetch latest issue/PR data"
    exit 1
  fi
  
  latest_number=$(echo "$latest" | jq '.[0].number')
  next_number=$((latest_number + 1))
  
  echo "Latest issue/PR number is #$latest_number, next number will likely be #$next_number"
  format_pr_link "$next_number"
}

# Attempt to copy text to clipboard using xclip, pbcopy, wl-copy, or win32yank
copy_to_clipboard() {
  local text="$1"
  local copied=false
  
  # Try xclip (Linux)
  if command -v xclip >/dev/null 2>&1; then
    echo "$text" | xclip -selection clipboard >/dev/null 2>&1 && copied=true
  fi
  
  # Try pbcopy (macOS)
  if [ "$copied" = false ] && command -v pbcopy >/dev/null 2>&1; then
    echo "$text" | pbcopy >/dev/null 2>&1 && copied=true
  fi
  
  # Try wl-copy (Wayland on Linux)
  if [ "$copied" = false ] && command -v wl-copy >/dev/null 2>&1; then
    echo "$text" | wl-copy >/dev/null 2>&1 && copied=true
  fi
  
  # Try win32yank (WSL on Windows)
  if [ "$copied" = false ] && command -v win32yank >/dev/null 2>&1; then
    echo "$text" | win32yank -i >/dev/null 2>&1 && copied=true
  fi
  
  if [ "$copied" = true ]; then
    echo "The link has been copied to your clipboard"
  else
    echo "Could not copy to clipboard - clipboard utilities not found"
  fi
}

# Format the PR link for CHANGELOG.md
format_pr_link() {
  local pr_number="$1"
  link="([filecoin-project/lotus#${pr_number}](https://github.com/filecoin-project/lotus/pull/${pr_number}))"
  echo -e "\nMarkdown link for CHANGELOG.md:"
  echo "$link"
  echo -e ""
  copy_to_clipboard "$link"
}

if ! check_existing_pr; then
  predict_next_number
fi