move source guard to the outer script

internal/p10k.zsh

@@ -27,13 +27,6 @@ if ! autoload -U is-at-least || ! is-at-least 5.1; then
   return 1
 fi
 
-if (( $+_P9K_SOURCED )); then
-  prompt_powerlevel9k_setup
-  return
-fi
-
-readonly _P9K_SOURCED=1
-
 source "${_p9k_installation_dir}/functions/utilities.zsh"
 source "${_p9k_installation_dir}/functions/icons.zsh"
 source "${_p9k_installation_dir}/functions/colors.zsh"

powerlevel9k.zsh-theme

@@ -20,14 +20,23 @@
 #zstyle ':vcs_info:*+*:*' debug true
 #set -o xtrace
 
-'builtin' 'typeset' "_p9k_aliases=$(
+() {
+  'builtin' 'emulate' '-L' 'zsh'
+
+  'builtin' 'local' "_p9k_aliases=$(
       'builtin' 'alias' '-rL'
       'builtin' 'alias' '-gL'
       'builtin' 'alias' '-sL')"
 
   'builtin' 'unalias' '-m' '*'
 
-_p9k_installation_dir=''
+  {
+    if (( $+_p9k_sourced )); then
+      prompt_powerlevel9k_setup
+      return
+    fi
+    typeset -gr _p9k_sourced=1
+    typeset -g _p9k_installation_dir=''
 
     if [[ -n $POWERLEVEL9K_INSTALLATION_DIR ]]; then
       _p9k_installation_dir=${POWERLEVEL9K_INSTALLATION_DIR:A}
@@ -40,12 +49,15 @@ else
         else
           >&2 print -P '%F{red}[ERROR]%f Powerlevel10k cannot figure out its installation directory.'
           >&2 print -P 'Please set %F{green}POWERLEVEL9K_INSTALLATION_DIR.%f'
+          return 1
         fi
       else
         _p9k_installation_dir=${${(%):-%x}:A:h}
       fi
     fi
 
-[[ -n $_p9k_installation_dir ]] && source $_p9k_installation_dir/internal/p10k.zsh
+    source $_p9k_installation_dir/internal/p10k.zsh
-
+  } always {
     eval "$_p9k_aliases"
+  }
+}