#!/bin/bash

set -e

#

# Handling community pull requests.

#

# The main way to handle community contributions is to contribute directly on the contributor's pull request.

# If not enabled, please ask the contributor to enable the option "Allow edits by maintainers".

# This allows maintainers to push commits to the contributor's branch.

# Then, use this script to mirror the PR to a new branch in the main repository.

# This allows running CI with the maintainer's permissions.

#

# Few hints:

# - Avoid merge commits with master and rebase the contributor's branch instead.

# - Avoid pushing changes to the mirror branch as it will be overwritten when rerunning the script.

#

# Usage: mirror-community-pull-request.sh <pr-number> [<target-branch>]

REPO="DataDog/dd-trace-java"

PR_NUMBER=$1

TARGET_BRANCH=${2:-master}

MIRROR_BRANCH="community-pr-$PR_NUMBER"

#

# Check arguments.

#

# Check if no arguments are provided

if [ $# -eq 0 ]; then

echo "Usage: $0 <pr-number> [<target-branch>]"

echo "<pr-number>: PR number to mirror"

echo "<target-branch>: Target branch for the mirror (default: master)"

echo ""

echo "This script mirrors a community PR to allow running CI with your own account."

echo "It creates a new branch 'community-pr-<number>' and pushes the PR changes."

exit 1

fi

# Check PR number is provided

if [ -z "$PR_NUMBER" ]; then

echo "❌ PR number is not provided"

exit 1

fi

# Validate PR number is numeric

if ! [[ "$PR_NUMBER" =~ ^[0-9]+$ ]]; then

echo "❌ PR number must be numeric"

exit 1

fi

#

# Check requirements.

#

echo "- Checking requirements"

# Check gh is installed

gh --version 1>/dev/null 2>&1 || { echo "❌ gh is not installed. Please install GitHub CLI."; exit 1; }

# Check that user is logged into gh cli

gh auth status 1>/dev/null 2>&1 || { echo "❌ Not logged into Github CLI. Please login with \`gh auth login\`."; exit 1; }

# Check jq is installed

jq --version 1>/dev/null 2>&1 || { echo "❌ jq is not installed. Please install jq."; exit 1; }

# Check there are no local changes

git diff --quiet --exit-code || { echo "❌ There are local changes. Please commit or stash them."; exit 1; }

#

# Fetch PR information.

#

echo "- Fetching PR #$PR_NUMBER details"

# Check if PR exists and get details

PR_DATA=$(gh pr view "$PR_NUMBER" --json headRepository,headRepositoryOwner,headRefName,title,number,state,author 2>/dev/null || echo "")

if [ -z "$PR_DATA" ]; then

echo "❌ PR #$PR_NUMBER not found"

exit 1

fi

# Parse PR details

FORK_REPO=$(echo "$PR_DATA" | jq -r '(.headRepository.nameWithOwner | select(. != "" and . != null)) // (.headRepositoryOwner.login + "/" + .headRepository.name) // empty')

FORK_BRANCH=$(echo "$PR_DATA" | jq -r '.headRefName // empty')

PR_TITLE=$(echo "$PR_DATA" | jq -r '.title // empty')

PR_AUTHOR=$(echo "$PR_DATA" | jq -r '.author.login // empty')

PR_LABELS=$(gh pr view "$PR_NUMBER" --json labels --jq '[.labels[].name] | join(",")')

if [ -z "$FORK_REPO" ] || [ -z "$FORK_BRANCH" ]; then

echo "❌ Could not determine fork repository or branch for PR #$PR_NUMBER"

exit 1

fi

#

# Create mirror branch.

#

echo "- Mirroring PR #$PR_NUMBER from $FORK_REPO:$FORK_BRANCH to $REPO:$MIRROR_BRANCH"

# Check if mirror branch already exists

echo "- Checking if mirror branch $MIRROR_BRANCH already exists locally"

if git show-ref --verify --quiet "refs/heads/$MIRROR_BRANCH" 2>/dev/null; then

echo -n "Branch $MIRROR_BRANCH already exists locally. Delete it to recreate? (y/n)"

read -r ANSWER

if [ "$ANSWER" = "y" ]; then

git branch -D "$MIRROR_BRANCH"

else

echo "Aborting."

exit 1

fi

fi

# Check if mirror branch exists on remote

echo "- Checking if mirror branch $MIRROR_BRANCH already exists on remote"

if git show-ref --verify --quiet "refs/remotes/origin/$MIRROR_BRANCH" 2>/dev/null; then

echo -n "Branch $MIRROR_BRANCH already exists on remote. Force push over it? (y/n)"

read -r ANSWER

if [ "$ANSWER" != "y" ]; then

echo "Aborting."

exit 1

fi

fi

# Fetch the PR branch from the fork directly (no remote needed)

git fetch --quiet "https://github.com/$FORK_REPO.git" "$FORK_BRANCH"

# Get list of commits from the PR to re-sign them

echo "- Getting list of commits from PR"

PR_COMMITS=$(gh pr view "$PR_NUMBER" --json commits --jq '.commits[].oid')

if [ -z "$PR_COMMITS" ]; then

echo "❌ No commits found in PR #$PR_NUMBER"

exit 1

fi

# Get current git branch for cleanup

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

# Create the mirror branch from target branch (we'll cherry-pick commits)

echo "- Creating mirror branch $MIRROR_BRANCH from $TARGET_BRANCH"

git fetch --quiet origin "$TARGET_BRANCH"

git checkout -b "$MIRROR_BRANCH" "origin/$TARGET_BRANCH"

#

# Mirror commits.

#

# Cherry-pick each commit with signature to ensure all commits are signed

echo "- Cherry-picking and signing commits from PR"

for COMMIT in $PR_COMMITS; do

echo " - Cherry-picking $COMMIT"

# Check if this is a merge commit

CHERRY_PICK_ARGS=("-S")

PARENT_COUNT=$(git rev-list --parents -n 1 "$COMMIT" 2>/dev/null | wc -w)

if [ "$PARENT_COUNT" -gt 2 ]; then

CHERRY_PICK_ARGS+=("-m" "1")

fi

if ! git cherry-pick "${CHERRY_PICK_ARGS[@]}" "$COMMIT"; then

# Check if it's an empty commit

if ! git diff --cached --quiet || ! git diff --quiet; then

echo "❌ Failed to cherry-pick merge commit $COMMIT"

echo "You may need to resolve conflicts manually"

exit 1

else

echo " (empty commit, skipping)"

git cherry-pick --skip

fi

fi

done

# Push the mirror branch to origin

echo "- Pushing $MIRROR_BRANCH to origin"

git push -u origin "$MIRROR_BRANCH" --no-verify --force-with-lease

#

# Create PR if it doesn't exist.

#

echo "- Checking if PR already exists for branch $MIRROR_BRANCH"

EXISTING_PR=$(gh pr list --head "$MIRROR_BRANCH" --json number --jq '.[0].number // empty' 2>/dev/null)

if [ -n "$EXISTING_PR" ]; then

MIRROR_PR_URL="https://github.com/$REPO/pull/$EXISTING_PR"

else

echo "- Creating new PR for mirror branch $MIRROR_BRANCH"

# Create PR body with reference to original

MIRROR_PR_BODY="This PR mirrors the changes from the original community contribution to enable CI testing with maintainer privileges.

**Original PR:** https://github.com/$REPO/pull/$PR_NUMBER

**Original Author:** @$PR_AUTHOR

**Original Branch:** $FORK_REPO:$FORK_BRANCH

Closes #$PR_NUMBER

---

*This is an automated mirror created to run CI checks. See tooling/mirror-community-pull-request.sh for details.*"

# Create the PR

CREATE_ARGS=(--base "$TARGET_BRANCH" --head "$MIRROR_BRANCH" --title "🪞 $PR_NUMBER - $PR_TITLE" --body "$MIRROR_PR_BODY")

if [ -n "$PR_LABELS" ]; then

CREATE_ARGS+=(--label "$PR_LABELS")

fi

MIRROR_PR_NUMBER=$(gh pr create "${CREATE_ARGS[@]}" 2>/dev/null | grep -o '[0-9]*$')

if [ -n "$MIRROR_PR_NUMBER" ]; then

echo "- Created mirror PR: #$MIRROR_PR_NUMBER"

MIRROR_PR_URL="https://github.com/$REPO/pull/$MIRROR_PR_NUMBER"

else

echo "- Failed to create PR automatically"

MIRROR_PR_URL="https://github.com/$REPO/compare/$TARGET_BRANCH...$MIRROR_BRANCH"

fi

fi

echo ""

echo "✅ Successfully mirrored PR #$PR_NUMBER"

echo " Original: https://github.com/$REPO/pull/$PR_NUMBER (@$PR_AUTHOR)"

echo " Mirror: $MIRROR_PR_URL"

echo " Branch: $REPO:$MIRROR_BRANCH"

#

# Clean up.

#

echo "- Restoring original branch"

git checkout "$CURRENT_BRANCH"

echo "Done."