github action that allows me to sync all the forks and store a report in markdown file, generated by github copilot

sync_forks_and_report.sh

#!/usr/bin/env bash
set -euo pipefail

# Config
USER_LOGIN="${1:-alexlib}"
REPORT_FILE="${2:-fork-sync-report.md}"
SYNC="${SYNC:-1}"            # SYNC=1 to sync clean forks, SYNC=0 to only report
PER_PAGE="${PER_PAGE:-100}"  # pagination size

tmp_json="$(mktemp)"
trap 'rm -f "$tmp_json"' EXIT

echo "# Fork sync report for \`$USER_LOGIN\`" > "$REPORT_FILE"
echo "" >> "$REPORT_FILE"
echo "_Generated: $(date -u +"%Y-%m-%d %H:%M:%SZ")_" >> "$REPORT_FILE"
echo "" >> "$REPORT_FILE"

echo "| Fork | Upstream | Default branch | Behind | Ahead | Action | Notes |" >> "$REPORT_FILE"
echo "|---|---|---:|---:|---:|---|---|" >> "$REPORT_FILE"

page=1
total_processed=0

while :; do
  # Fetch forks for the user (only repositories where fork=true)
  gh api "users/${USER_LOGIN}/repos?type=owner&per_page=${PER_PAGE}&page=${page}" > "$tmp_json"

  # Stop if empty
  if [[ "$(jq 'length' < "$tmp_json")" -eq 0 ]]; then
    break
  fi

  # Iterate repos; filter fork=true
  jq -c '.[] | select(.fork == true) | {full_name, html_url, default_branch, archived, disabled}' < "$tmp_json" \
  | while read -r repo; do
      total_processed=$((total_processed+1))

      full_name="$(jq -r '.full_name' <<<"$repo")"
      fork_url="$(jq -r '.html_url' <<<"$repo")"
      default_branch="$(jq -r '.default_branch' <<<"$repo")"
      archived="$(jq -r '.archived' <<<"$repo")"
      disabled="$(jq -r '.disabled' <<<"$repo")"

      action="skipped"
      notes=""

      # Determine upstream via the repo API (parent exists for forks)
      parent_full_name="$(gh api "repos/${full_name}" --jq '.parent.full_name // empty' 2>/dev/null || true)"
      parent_url="$(gh api "repos/${full_name}" --jq '.parent.html_url // empty' 2>/dev/null || true)"

      if [[ -z "${parent_full_name}" ]]; then
        # Not all forks expose parent (or permissions), but usually they do.
        echo "| [\`${full_name}\`](${fork_url}) | (unknown) | \`${default_branch}\` |  |  | skipped | no upstream parent found (not a fork? permissions?) |" >> "$REPORT_FILE"
        continue
      fi

      # Skip archived/disabled forks
      if [[ "${archived}" == "true" || "${disabled}" == "true" ]]; then
        notes="archived/disabled"
        echo "| [\`${full_name}\`](${fork_url}) | [\`${parent_full_name}\`](${parent_url}) | \`${default_branch}\` |  |  | skipped | ${notes} |" >> "$REPORT_FILE"
        continue
      fi

      # Compare upstream default branch to fork default branch.
      # This works even if branch names differ, but we use each repo's default branch.
      upstream_default_branch="$(gh api "repos/${parent_full_name}" --jq '.default_branch')"

      # Compare: base=upstream, head=fork (needs owner:branch syntax)
      compare_json="$(gh api "repos/${parent_full_name}/compare/${upstream_default_branch}...${full_name}:${default_branch}" 2>/dev/null || true)"

      if [[ -z "${compare_json}" ]]; then
        echo "| [\`${full_name}\`](${fork_url}) | [\`${parent_full_name}\`](${parent_url}) | \`${default_branch}\` |  |  | skipped | compare failed (branch mismatch? force-push? permissions?) |" >> "$REPORT_FILE"
        continue
      fi

      behind_by="$(jq -r '.behind_by // empty' <<<"$compare_json")"
      ahead_by="$(jq -r '.ahead_by // empty' <<<"$compare_json")"
      status="$(jq -r '.status // empty' <<<"$compare_json")"

      # Decide action
      if [[ "${behind_by}" =~ ^[0-9]+$ && "${ahead_by}" =~ ^[0-9]+$ ]]; then
        if [[ "${behind_by}" -gt 0 && "${ahead_by}" -eq 0 ]]; then
          if [[ "${SYNC}" == "1" ]]; then
            if gh repo sync "${full_name}" --branch "${default_branch}" >/dev/null 2>&1; then
              action="synced"
              notes="clean fork; fast-forwarded from upstream (${upstream_default_branch})"
            else
              action="failed"
              notes="sync command failed"
            fi
          else
            action="would-sync"
            notes="clean fork; report-only mode"
          fi
        elif [[ "${behind_by}" -eq 0 && "${ahead_by}" -eq 0 ]]; then
          action="up-to-date"
          notes="no changes"
        elif [[ "${ahead_by}" -gt 0 && "${behind_by}" -eq 0 ]]; then
          action="skipped"
          notes="fork is ahead of upstream (local commits); not syncing"
        else
          action="skipped"
          notes="diverged (ahead and behind); not syncing"
        fi
      else
        action="skipped"
        notes="could not parse ahead/behind"
      fi

      # Add helpful compare link
      compare_url="https://github.com/${parent_full_name}/compare/${upstream_default_branch}...${full_name}:${default_branch}"

      echo "| [\`${full_name}\`](${fork_url}) | [\`${parent_full_name}\`](${parent_url}) | \`${default_branch}\` | ${behind_by:-} | ${ahead_by:-} | ${action} | ${notes}. [Compare](${compare_url}) |" >> "$REPORT_FILE"
    done

  page=$((page+1))
done

echo "" >> "$REPORT_FILE"
echo "## How to read this report" >> "$REPORT_FILE"
echo "" >> "$REPORT_FILE"
echo "- **synced**: fork was behind and had no local commits; it was fast-forwarded." >> "$REPORT_FILE"
echo "- **skipped (ahead/diverged)**: fork has commits not in upstream and needs manual review (PR/rebase/cherry-pick)." >> "$REPORT_FILE"
echo "- **compare failed**: usually branch mismatch or permission/API limitation; open the repo and verify default branch/upstream." >> "$REPORT_FILE"

echo "Wrote report to: ${REPORT_FILE}" >&2