Merge pull request #1128 from ymage/fix_virtualenv_prompt

[Bugfix] virtualenv prompt displaying

powerlevel9k.zsh-theme

@@ -1648,9 +1648,11 @@ prompt_vi_mode() {
 # https://virtualenv.pypa.io/en/latest/
 prompt_virtualenv() {
   local virtualenv_path="$VIRTUAL_ENV"
-  if [[ -n "$virtualenv_path" && -z "$VIRTUAL_ENV_DISABLE_PROMPT" ]]; then
+
+  # Early exit; $virtualenv_path must always be set.
+  [[ -z "$virtualenv_path" ]] && return
+
   "$1_prompt_segment" "$0" "$2" "blue" "$DEFAULT_COLOR" "$(basename "$virtualenv_path")" 'PYTHON_ICON'
-  fi
 }
 
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