simplify worker bootstrap

internal/worker.zsh

@@ -1,7 +1,7 @@
 # invoked in worker: _p9k_worker_main <timeout>
 function _p9k_worker_main() {
   emulate -L zsh
-  setopt no_hist_expand extended_glob no_prompt_bang prompt_percent prompt_subst no_aliases
+  setopt no_hist_expand extended_glob no_prompt_bang prompt_percent prompt_subst no_aliases no_bgnice
 
   zmodload zsh/system                || return
   zmodload zsh/zselect               || return
@@ -15,6 +15,7 @@ function _p9k_worker_main() {
   local -A inflight  # fd => id$'\x1f'sync
   local -ri _p9k_worker_runs_me=1
 
+  {
     while zselect -a ready 0 ${(k)inflight}; do
       [[ $ready[1] == -r ]] || return
       for fd in ${ready:1}; do
@@ -59,6 +60,9 @@ function _p9k_worker_main() {
         fi
       done
     done
+  } always {
+    kill -- -$$
+  }
 }
 
 typeset -g  _p9k__worker_pid
@@ -237,6 +241,7 @@ function _p9k_worker_receive() {
 }
 
 function _p9k_worker_start() {
+  setopt no_bgnice
   {
     [[ -n $_p9k__worker_resp_fd ]] && return
     _p9k__worker_file_prefix=${TMPDIR:-/tmp}/p10k.worker.$EUID.$$.$EPOCHSECONDS
@@ -253,17 +258,21 @@ function _p9k_worker_start() {
     trace=x
 
     local fifo=$_p9k__worker_file_prefix.fifo
-    local cmd=(
-      'emulate zsh'
-      '{ mkfifo '${(q)fifo}' && exec >&4 && echo -n "s$$\x1e" && exec 0<'${(q)fifo}' || exit } always { rm -f '${(q)fifo}' }'
-      'IFS= read -rd $'\''\x1e'\'' && eval $REPLY')
-    local setsid=${commands[setsid]:-/usr/local/opt/util-linux/bin/setsid}
-    [[ -x $setsid ]] && setsid=${(q)setsid} || setsid=
     local zsh=${${:-/proc/self/exe}:A}
     [[ -x $zsh ]] || zsh=zsh
-    cmd="$setsid ${(q)zsh} --nobgnice --noaliases -${trace}dfc ${(q)${(j:; :)cmd}} &!"
+    local bootstrap=(
+      '"emulate" "-L" "zsh" "-o" "no_aliases"'
+      '{ mkfifo '${(q)fifo}' && exec >&4 && echo -n "s$$\x1e" && exec 0<'${(q)fifo}' || exit } always { rm -f '${(q)fifo}' }'
+      'IFS= read -rd $'\''\x1e'\'' && eval $REPLY')
+    local child='"eval" "$_p9k_worker_bootstrap" &!'
+    local parent=(
+      '"emulate" "-L" "zsh" "-o" "no_aliases" "-o" "no_bgnice"'
+      ${(qqq)zsh}' -'${trace}'dfc '${(qqq)child}
+    )
     sysopen -r -o cloexec -u _p9k__worker_resp_fd <(
-      $zsh --nobgnice --noaliases -${trace}dfmc $cmd </dev/null 4>&1 &>>$log_file &!) || return
+      _p9k_worker_bootstrap=${(j:; :)bootstrap} \
+      </dev/null 4>&1 &>>$log_file $zsh -${trace}dfmc \
+      ${(j:; :)parent}) || return
     zle -F $_p9k__worker_resp_fd _p9k_worker_receive
     _p9k__worker_shell_pid=$sysparams[pid]
     add-zsh-hook zshexit _p9k_worker_cleanup