post-commit/post-checkout hooks use `nohup`, which Git for Windows' shell lacks — rebuild fails silently

[rv-us]

Summary

The git hooks installed by graphify hook install background the graph rebuild with nohup ... &. Git for Windows' bundled shell (MSYS/MINGW64) does not ship nohup (nor
setsid), so the line dies with nohup: command not found and the rebuild never runs. Worse, it fails silently: git commit / git pull return success, no error surfaces to
the user, and the knowledge graph just quietly goes stale.

Environment

• OS: Windows 11
• Shell running the hooks: C:\Program Files\Git\usr\bin\sh.exe (Git for Windows, MSYSTEM=MINGW64)
• git version 2.42.0.windows.2
• graphify installed under conda Python; graphify hook install reported success and wrote post-commit + post-checkout.

Steps to reproduce

1. On Git for Windows, run graphify hook install in a repo with an existing graphify-out/.
2. git commit (or pull a branch that fires post-checkout).
3. Observe the rebuild log at ~/.cache/graphify-rebuild.log.

Expected

The graph rebuilds in the background and graph.json / GRAPH_REPORT.md update.

Actual

The log contains:

.git/hooks/post-commit: line 101: nohup: command not found

No rebuild happens. The commit/pull exits 0, so the user gets no signal that the graph is now stale. The same flaw is in the post-checkout hook.

Root cause

The hook templates use:

nohup "$GRAPHIFY_PYTHON" -c "...rebuild..." >> "$_GRAPHIFY_LOG" 2>&1 < /dev/null &
disown 2>/dev/null || true

nohup is a coreutils/util-linux tool that is absent from the minimal MSYS2 runtime Git for Windows bundles. setsid is also absent, so it isn't a drop-in substitute. There's no
package manager (pacman) in a stock Git for Windows install to add it either.

Suggested fix

graphify already requires Python, so let Python do the detaching instead of nohup/setsid — this is cross-platform and dependency-free. A tiny launcher spawns the real rebuild as
a fully detached process and returns immediately:

import os, sys, subprocess

cmd = [sys.executable, "-c", REBUILD_SRC]
kwargs = dict(stdout=open(LOG, "a", buffering=1),
              stderr=subprocess.STDOUT,
              stdin=subprocess.DEVNULL,
              cwd=os.getcwd(), close_fds=True)

if os.name == "nt":
    DETACHED_PROCESS = 0x00000008
    CREATE_NEW_PROCESS_GROUP = 0x00000200
    CREATE_BREAKAWAY_FROM_JOB = 0x01000000
    base = DETACHED_PROCESS | CREATE_NEW_PROCESS_GROUP
    try:
        subprocess.Popen(cmd, creationflags=base | CREATE_BREAKAWAY_FROM_JOB, **kwargs)
    except OSError:
        subprocess.Popen(cmd, creationflags=base, **kwargs)
else:
    subprocess.Popen(cmd, start_new_session=True, **kwargs)   # POSIX setsid equivalent

The hook then just runs "$GRAPHIFY_PYTHON" -c "$LAUNCHER" — no nohup, no &, returns instantly, and the detached child survives the hook (and its shell) exiting.