Ensure $key_info is populated before use

modules/history-substring-search/init.zsh

@@ -28,17 +28,19 @@ fi
 # Key Bindings
 #
 
-# Emacs
-bindkey -M emacs "$key_info[Control]P" history-substring-search-up
-bindkey -M emacs "$key_info[Control]N" history-substring-search-down
+if [[ -n $key_info ]]; then
+  # Emacs
+  bindkey -M emacs "$key_info[Control]P" history-substring-search-up
+  bindkey -M emacs "$key_info[Control]N" history-substring-search-down
 
-# Vi
-bindkey -M vicmd "k" history-substring-search-up
-bindkey -M vicmd "j" history-substring-search-down
+  # Vi
+  bindkey -M vicmd "k" history-substring-search-up
+  bindkey -M vicmd "j" history-substring-search-down
 
-# Emacs and Vi
-for keymap in 'emacs' 'viins'; do
+  # Emacs and Vi
+  for keymap in 'emacs' 'viins'; do
     bindkey -M "$keymap" "$key_info[Up]" history-substring-search-up
     bindkey -M "$keymap" "$key_info[Down]" history-substring-search-down
-done
+  done
+fi