allow prompt to skip expensive display functions conditionally

nix/home.nix

@@ -103,6 +103,22 @@ in {
       bindkey '^[[B' history-substring-search-down
       bindkey -M viins 'jj' vi-cmd-mode
 
+      # utility for storing functions under a new name
+      save_function() {
+        local ORIG_FUNC=$(declare -f $1)
+        local NEWNAME_FUNC="$2''${ORIG_FUNC#$1}"
+        eval "$NEWNAME_FUNC"
+      }
+
+      # Override an oh-my-zsh/lib/git.sh function so that old repositories
+      # don't slow the shell down
+      save_function git_prompt_status old_git_prompt_status
+      function git_prompt_status() {
+        if [[ "$(command git config --get oh-my-zsh.hide-status 2>/dev/null)" != "1" ]]; then
+          old_git_prompt_status
+        fi
+      }
+
       eval "$(direnv hook zsh)"
     '');