ship

/ship

Preflight: worktree guard

Task-scoped mutating skill — must run from a worktree, not the main checkout. Contract: skills/_shared/worktree-guard.md.

TOPLEVEL="$(git rev-parse --show-toplevel 2>/dev/null || echo '')"
if [ -z "$TOPLEVEL" ]; then
  echo "✗ worktree-guard: not inside a git repository" >&2
  exit 1
fi
BRANCH="$(git branch --show-current 2>/dev/null || echo '')"
DEFAULT_BRANCH="$(git symbolic-ref --short refs/remotes/origin/HEAD 2>/dev/null | sed 's@^origin/@@' || echo 'main')"
if [ -f "$TOPLEVEL/.forge/worktree-task.json" ]; then
  echo "✓ worktree-guard: $TOPLEVEL ($BRANCH)"
elif [ "$BRANCH" = "${DEFAULT_BRANCH:-main}" ]; then
  echo "✗ worktree-guard: refusing to run on default branch '$BRANCH' from $TOPLEVEL" >&2
  echo "  Parallel Claude Code sessions on the main checkout clobber each other's HEAD." >&2
  echo "  → cd into an existing worktree, or run /pickup-task to create one." >&2
  exit 1
else
  echo "⚠ worktree-guard: no .forge/worktree-task.json at $TOPLEVEL (branch: $BRANCH)" >&2
  echo "  Proceeding, but this worktree may be manually-created or stale." >&2
fi

SPEC-changes signal (informational — never blocks the ship)

After the worktree guard and before the gates, surface whether spec/ changed since THIS task was claimed (FORGE-164 — the push-time half of the FORGE-114 mitigation). This is strictly informational: it NEVER blocks the ship; it just makes a stale-claim risk visible in the PR.

# TASK_ID is the current task (from .forge/worktree-task.json).
forge orchestrate spec-diff "$TASK_ID" --json

• If the data field is non-null (commits touching spec/ landed since the claim), do two things:
  1. Print the rendered block to the operator.
  2. Add a ### ⚠ SPEC changes since this task was claimed section to the PR body (see the template below) listing the commit summaries, plus a pointer to forge orchestrate spec-diff --all-active for OTHER affected tasks.
• If data is null, omit the section entirely — no SPEC drift to report.