catchup

Catchup: Branch Activity Since Last Contribution

Produce a focused "welcome back" report for a developer returning to a feature branch, so they can catch up on what others (or they themselves) changed while they were away.

Input

$ARGUMENTS — optional identity of the returning developer:

• empty → use the local git config user.email (and user.name)
• an email → match commits by author.email
• a name (or fragment) → match commits by author.name (case-insensitive)

Examples:

• /catchup — catch up the current git user
• /catchup [email protected] — catch up Alice by email
• /catchup "Alice Martin" — catch up Alice by name

Workflow

1. Resolve context — run, in parallel where possible:

   • git rev-parse --abbrev-ref HEAD → current branch (abort with a clear message if HEAD is detached or the branch is main/master).
   • git config user.email and git config user.name → default identity.
   • git remote show origin | sed -n 's/.*HEAD branch: //p' (fallback to main) → base branch.
   • git fetch --quiet if a remote exists, so comparisons use up-to-date refs. Skip silently on failure (offline).

2. Resolve the developer:

   • Use $ARGUMENTS if provided; otherwise the local git identity.
   • Detect whether the argument looks like an email (contains @) to choose --author=<email> vs --author=<name>.
   • Record the resolved display string for the report header.

3. Find the developer's last commit on this branch (merge-base scoped):

   git log <base>..HEAD --author="<dev>" -n 1 --format="%H %ci %s"
   

   • If a commit is found → use it as the since anchor (<sha>..HEAD).
   • If none → the dev has never committed on this branch. Use the branch divergence point as the anchor: git merge-base <base> HEAD. Flag this in the report as "first time on this branch".

4. Gather activity between the anchor and HEAD (read-only commands only):

   • Commits with authors and dates: git log <anchor>..HEAD --format="%h|%an|%ae|%cr|%s" --no-merges
   • Author breakdown: git shortlog -sne <anchor>..HEAD --no-merges
   • Diff stats (files + lines): git diff --stat <anchor>..HEAD
   • Machine-readable per-file churn (for top-changed files): git diff --numstat <anchor>..HEAD
   • High-signal diffs for the top 3–5 most-changed files: git diff <anchor>..HEAD -- <path> (truncate each to the first ~200 lines of diff in the report; link the rest by filename).
   • Merge commits summary (if any), only listed — not expanded: git log <anchor>..HEAD --merges --format="%h %s"