Feat: improve run_waypipe handling, without needing temporary files

home/zsh/files/waypipe.zsh

@@ -1,4 +1,15 @@
-if [ "$PREVIOUS_SESSION_ID" != "" ]; then
+if [ -n "$REMOTE_PATH" ]; then
+    # Fresh `s <host>` connection: the initial working directory is handed over in
+    # REMOTE_PATH (an env var is the only channel that survives waypipe's command
+    # transport intact — shell grouping like `cd …; exec …` does not). cd into it,
+    # then unset so it does NOT leak to child shells: a lingering exported
+    # REMOTE_PATH is what made every new zellij pane jump back to this same path
+    # instead of inheriting the pane's own cwd.
+    [ -d "$REMOTE_PATH" ] && cd "$REMOTE_PATH"
+    unset REMOTE_PATH
+fi
+
+if [ -n "$PREVIOUS_SESSION_ID" ]; then
     # Spawned as a new window/terminal for an existing remote session (by the
     # niri/hyprland keybind). Inherit that session's working directory: find a
     # live shell whose SSH_SESSION_ID (carried in its environment) matches and
@@ -12,7 +23,16 @@ if [ "$PREVIOUS_SESSION_ID" != "" ]; then
         # fail quietly into the pipe instead of raising a shell error.
         if cat "$_environ" 2>/dev/null | tr '\0' '\n' | grep -Fxq "SSH_SESSION_ID=$PREVIOUS_SESSION_ID"; then
             [ "$(cat /proc/$_pid/comm 2>/dev/null)" = zsh ] || continue
+            # SSH_SESSION_ID is exported, so transient `zsh -c …` subshells (prompt
+            # hooks, zellij helpers) inherit it too — but they aren't real session
+            # panes and often sit at /. Skip anything invoked in command mode; only
+            # interactive login/pane shells should count.
+            cat /proc/$_pid/cmdline 2>/dev/null | tr '\0' '\n' | grep -Fxq -- -c && continue
             _c=$(readlink -e /proc/$_pid/cwd 2>/dev/null) || continue
+            # A login shell still sitting at / is a helper forked during startup
+            # (e.g. p10k) that never ran the REMOTE_PATH cd, not a shell the user
+            # works in. Real panes have always cd'd somewhere; skip root.
+            [ "$_c" = / ] && continue
             if [ -n "$_c" ] && [ "$_pid" -gt "$_best_pid" ]; then
                 _best_pid=$_pid
                 _prev_cwd=$_c
@@ -30,18 +50,25 @@ function run_waypipe() {
     fi
     local SSH_SESSION_ID=$RANDOM REMOTE_PATH
     # Map the current path relative to $HOME so it resolves to the remote user's
-    # home even when the username differs (the remote shell expands $HOME).
+    # home even when the username differs (the remote shell expands $HOME while
+    # parsing the command below).
     if [[ "$PWD" == "$HOME" || "$PWD" == "$HOME"/* ]]; then
         REMOTE_PATH="\$HOME${PWD#$HOME}"
     else
         REMOTE_PATH="$PWD"
     fi
-    # cd into the mirrored path before the interactive shell starts, so the cwd
-    # is never carried in an inherited env var (which would leak to every child
-    # shell and override the cwd of new zellij panes). SSH_SESSION_ID stays in
-    # the environment on purpose: it is the token the WM keybind above uses to
-    # locate this session's shells later.
-    waypipe -n ssh -t "$1" "cd \"$REMOTE_PATH\" 2>/dev/null; exec env SSH_SESSION_ID=$SSH_SESSION_ID zsh --login"
+    # Hand off the initial cwd and session token as a plain `env VAR=val … zsh`
+    # argv. This must stay free of shell grouping/metacharacters: waypipe rejoins
+    # and re-splits the command on whitespace and runs the leading word as a
+    # program, so `env` (a real binary) works but `cd …; exec …` would not.
+    #
+    # SSH_SESSION_ID is placed in TWO environments on purpose:
+    #   - the leading prefix exports it into the LOCAL waypipe/ssh process, where
+    #     the niri/hyprland "duplicate window" keybind reads it out of
+    #     /proc/<ssh-pid>/environ to learn which session to clone;
+    #   - the `env SSH_SESSION_ID=…` sets it on the REMOTE zsh, where the scan
+    #     block above locates this session's shells by matching it.
+    SSH_SESSION_ID=$SSH_SESSION_ID waypipe -n ssh -t "$1" env REMOTE_PATH=\"$REMOTE_PATH\" SSH_SESSION_ID=$SSH_SESSION_ID zsh --login
 }
 
 alias s='run_waypipe'