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diff --git a/scripts/hypr-live-update-guard b/scripts/hypr-live-update-guard
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+#!/bin/sh
+# SPDX-License-Identifier: GPL-3.0-or-later
+# hypr-live-update-guard - abort a live GPU/compositor library upgrade.
+#
+# Installed as a pacman PreTransaction hook. When an upgrade transaction
+# includes GPU/compositor runtime libraries (mesa, hyprland, wayland, GPU
+# drivers, ...) AND a Hyprland session is running, this aborts the
+# transaction BEFORE any package is swapped. Replacing those libraries out
+# from under a live compositor makes the next GPU-lib call hit a now
+# "(deleted)" file and SIGABRT, taking the Wayland clients down with it
+# (hit on ratio 2026-06-07: mesa + hyprland upgraded live, Hyprland crashed
+# and took awww/insync/emacs with it). Aborting at PreTransaction is the
+# safe point: nothing has been replaced yet, so the running session is
+# untouched and the user can re-run the upgrade from a TTY.
+#
+# Pacman feeds the matched package names on stdin (NeedsTargets).
+#
+# Test seams / overrides (env):
+#   HYPR_GUARD_RUNNING     1/0 forces the running check (default: pgrep Hyprland)
+#   HYPR_ALLOW_LIVE_UPDATE 1 proceeds anyway (skip the guard)
+#   HYPR_GUARD_SENTINEL    path whose existence also proceeds anyway
+#                          (default /run/archsetup-allow-live-gpu-update,
+#                          cleared on reboot since /run is tmpfs)
+
+set -u
+
+sentinel="${HYPR_GUARD_SENTINEL:-/run/archsetup-allow-live-gpu-update}"
+
+# Explicit override: the user knows what they're doing.
+if [ "${HYPR_ALLOW_LIVE_UPDATE:-0}" = "1" ] || [ -e "$sentinel" ]; then
+    exit 0
+fi
+
+hyprland_running() {
+    if [ -n "${HYPR_GUARD_RUNNING:-}" ]; then
+        [ "$HYPR_GUARD_RUNNING" = "1" ]
+        return
+    fi
+    pgrep -x Hyprland >/dev/null 2>&1
+}
+
+# No live session means no live swap to worry about. Let the upgrade run --
+# this is exactly the from-a-TTY-after-logout path the warning points to.
+hyprland_running || exit 0
+
+# Collect the triggering packages (stdin from NeedsTargets) for the message.
+pkgs=$(cat 2>/dev/null | sort -u | tr '\n' ' ')
+
+cat >&2 <<EOF
+
+==========================================================================
+ BLOCKED: live GPU/compositor library upgrade while Hyprland is running
+==========================================================================
+ Packages in this upgrade can crash the running compositor if swapped now:
+   ${pkgs:-(GPU/compositor runtime libraries)}
+
+ Replacing these out from under a live Hyprland session makes the next
+ GPU-lib call hit a deleted library and SIGABRT, taking your Wayland apps
+ down with it (and risking an unclean shutdown).
+
+ Do it safely instead -- from a TTY with Hyprland stopped:
+   1. Log out of Hyprland, or switch to a console (Ctrl+Alt+F2) and log in.
+   2. Re-run the upgrade there:  sudo pacman -Syu
+
+ To override and proceed anyway (not recommended while Hyprland runs):
+   sudo touch $sentinel && sudo pacman -Syu
+==========================================================================
+
+EOF
+exit 1