oh-my-zsh/plugins/virtualenvwrapper/virtualenvwrapper.plugin.zsh

virtualenvwrapper='virtualenvwrapper.sh'
if (( $+commands[$virtualenvwrapper] )); then

  source ${${virtualenvwrapper}:c}

  if [[ "$WORKON_HOME" == "" ]]; then
    echo "\$WORKON_HOME is not defined so ZSH plugin virtualenvwrapper will not work"
  else

    if [[ ! $DISABLE_VENV_CD -eq 1 ]]; then
      # Automatically activate Git projects's virtual environments based on the
      # directory name of the project. Virtual environment name can be overridden
      # by placing a .venv file in the project root with a virtualenv name in it
      function workon_cwd {
        if [ ! $WORKON_CWD ]; then
          WORKON_CWD=1
          # Check if this is a Git repo
          PROJECT_ROOT=`git rev-parse --show-toplevel 2> /dev/null`
          if (( $? != 0 )); then
            PROJECT_ROOT="."
          fi
          # Check for virtualenv name override
          if [[ -f "$PROJECT_ROOT/.venv" ]]; then
            ENV_NAME=`cat "$PROJECT_ROOT/.venv"`
          elif [[ -f "$PROJECT_ROOT/.venv/bin/activate" ]];then
            ENV_NAME="$PROJECT_ROOT/.venv"
          elif [[ "$PROJECT_ROOT" != "." ]]; then
            ENV_NAME=`basename "$PROJECT_ROOT"`
          else
            ENV_NAME=""
          fi
          if [[ "$ENV_NAME" != "" ]]; then
            # Activate the environment only if it is not already active
            if [[ "$VIRTUAL_ENV" != "$WORKON_HOME/$ENV_NAME" ]]; then
              if [[ -e "$WORKON_HOME/$ENV_NAME/bin/activate" ]]; then
                workon "$ENV_NAME" && export CD_VIRTUAL_ENV="$ENV_NAME"
              elif [[ -e "$ENV_NAME/bin/activate" ]]; then
                source $ENV_NAME/bin/activate && export CD_VIRTUAL_ENV="$ENV_NAME"
              fi
            fi
          elif [[ -n $CD_VIRTUAL_ENV && -n $VIRTUAL_ENV ]]; then
            # We've just left the repo, deactivate the environment
            # Note: this only happens if the virtualenv was activated automatically
            deactivate && unset CD_VIRTUAL_ENV
          fi
          unset PROJECT_ROOT
          unset WORKON_CWD
        fi
      }

      # Append workon_cwd to the chpwd_functions array, so it will be called on cd
      # http://zsh.sourceforge.net/Doc/Release/Functions.html
      # TODO: replace with 'add-zsh-hook chpwd workon_cwd' when oh-my-zsh min version is raised above 4.3.4
      if (( ${+chpwd_functions} )); then
        if (( $chpwd_functions[(I)workon_cwd] == 0 )); then
          set -A chpwd_functions $chpwd_functions workon_cwd
        fi
      else
        set -A chpwd_functions workon_cwd
      fi
    fi
  fi
else
  print "zsh virtualenvwrapper plugin: Cannot find ${virtualenvwrapper}. Please install with \`pip install virtualenvwrapper\`."
fi