receive-pack

#!/usr/bin/env bash
#
# Example objgitd receive-pack hook.
#
# objgitd runs this script after a successful push when started with
# -allow-hooks. It does NOT run on a normal `git` server — it only has meaning
# when this repository is served by objgitd.
#
# Execution environment (see CLAUDE.md "Push hooks"):
#   * It runs in a kefka virtual shell, NOT a real OS shell. Only kefka's
#     built-in commands are available (coreutils: cat, ls, echo, printf, head,
#     tail, cut, sort, uniq, wc, sha256sum, grep, ...). There is no PATH to
#     system binaries, no network, and no `git`.
#   * /src is a READ-ONLY checkout of the pushed commit. The working directory
#     starts here.
#   * /tmp is the only writable location (also $HOME and $TMPDIR). Writing
#     anywhere else fails; a redirect into /src aborts the script.
#   * The hook runs asynchronously after the push response, so it cannot reject
#     a push. Its stdout/stderr and exit status are written to the server log
#     only — the person pushing never sees them.
#   * One run happens per created or updated branch. Branch deletions are
#     skipped.
#
# These variables describe the ref that triggered this run:
#   OBJGIT_REPO      repository path, e.g. /myproject.git
#   OBJGIT_SERVICE   always "receive-pack"
#   OBJGIT_REF       full ref name, e.g. refs/heads/main
#   OBJGIT_BRANCH    short branch name, e.g. main
#   OBJGIT_OLD_SHA   previous tip (all zeros when the branch was created)
#   OBJGIT_NEW_SHA   new tip
# git's usual "<old> <new> <ref>" line is also fed on stdin.

echo "push to ${OBJGIT_REPO} ${OBJGIT_REF}: ${OBJGIT_OLD_SHA} -> ${OBJGIT_NEW_SHA}"

# /src is the checkout of the new commit. List what landed at the top level.
echo "top-level contents:"
ls /src

# Read a file out of the push and act on it.
if [ -f /src/go.mod ]; then
	module="$(head -n 1 /src/go.mod | cut -d' ' -f2)"
	echo "go module: ${module}"
fi

# Scratch work goes in /tmp. Here we record a tiny build manifest.
manifest=/tmp/manifest.txt
echo "ref ${OBJGIT_REF}" > "${manifest}"
echo "sha ${OBJGIT_NEW_SHA}" >> "${manifest}"
echo "manifest (${manifest}):"
cat "${manifest}"

echo "hook done"