From 7d95850461f7912b84bd08514eecfcd8e20c0cdb Mon Sep 17 00:00:00 2001
From: veg <veg@silentio.us>
Date: Sat, 4 Jul 2026 09:25:27 +0000
Subject: [PATCH] fix: .party-notify uses PARTY_TMUX, not bare tmux from PATH

---
 party                       | 15 ++++++++++++---
 tests/90-notifications.bats | 11 +++++++++++
 2 files changed, 23 insertions(+), 3 deletions(-)

diff --git a/party b/party
index cb6e1ce..b580934 100755
--- a/party
+++ b/party
@@ -441,14 +441,23 @@ tmux_party_setup_server() {
     # keeps it out of typical `ls` listings. The per-party private dir
     # hosts at most one socket so a fixed name is safe.
     notify_script="${sock%/*}/.party-notify"
-    cat > "$notify_script" <<'EOF'
+    # Two heredocs: the first (expanding) pins the tmux binary the party
+    # was hosted with — a bare `tmux` from the server's PATH may be a
+    # different, older binary than $PARTY_TMUX, which is the whole reason
+    # PARTY_TMUX exists. The second (quoted) is the static body. A
+    # PARTY_TMUX containing a double quote or $ would break the pin;
+    # that's accepted — it's the host's own env var on their own party.
+    cat > "$notify_script" <<EOF
 #!/bin/sh
+tmux="$PARTY_TMUX"
+EOF
+    cat >> "$notify_script" <<'EOF'
 # Auto-generated by party. Fan a display-message out to every client
 # of the party server. Args: $1 = socket, $2 = client_user, $3 = "joined"|"left"
 sock="$1"; user="$2"; verb="$3"
-tmux -S "$sock" list-clients -F '#{client_name}' 2>/dev/null \
+"$tmux" -S "$sock" list-clients -F '#{client_name}' 2>/dev/null \
   | while read -r c; do
-        tmux -S "$sock" display-message -c "$c" "$user $verb the party" 2>/dev/null || :
+        "$tmux" -S "$sock" display-message -c "$c" "$user $verb the party" 2>/dev/null || :
     done
 EOF
     chmod 0755 "$notify_script"
diff --git a/tests/90-notifications.bats b/tests/90-notifications.bats
index 1f6879b..6eb06a5 100644
--- a/tests/90-notifications.bats
+++ b/tests/90-notifications.bats
@@ -51,3 +51,14 @@ party_rec() { printf '%s/party-%s:%s.d/roster\n' "$PARTY_SOCKET_DIR" "$USER" "$1
   [ "$g" = "$TMUX_PARTY_GROUP" ] \
     || { echo "notify_script group=$g, expected $TMUX_PARTY_GROUP"; false; }
 }
+
+@test ".party-notify pins the PARTY_TMUX binary used at host time" {
+  "$PARTY_BIN" host pintmux
+  rec=$(party_rec pintmux)
+  sock=$(awk -F= '$1=="SOCKET"{print $2}' "$rec")
+  notify_script="${sock%/*}/.party-notify"
+  # The helper must not reach for a bare `tmux` from PATH: it pins the
+  # binary the party was hosted with (PARTY_TMUX, default "tmux").
+  grep -q "^tmux=\"${PARTY_TMUX:-tmux}\"$" "$notify_script"
+  ! grep -qE '^[[:space:]]*tmux -S' "$notify_script"
+}