rehydrate_pane(pane)

    if pane.line_cache[i] == nil then
      pane.line_cache[i] = {}
    end

      pane.line_cache[i].fragments = nil
      pane.line_cache[i].screen_line_starting_pos = nil

--?   print('update pane bounds')

--?   print('plan draw')

-- The basic text editor buffer (editor State) in edit.lua and text.lua
-- assumes there's always an element in line_cache for every line. However,
-- this can be a lot of overhead when we have hundreds of buffers. So pensieve
-- needs to violate this assumption while hiding it from buffer helpers.

function rehydrate_pane(pane)
  for i=1,#pane.lines do
    -- don't clobber starty/startpos if they exist
    if pane.line_cache[i] == nil then
      pane.line_cache[i] = {}
    end
    Text.clear_screen_line_cache(pane, i)
  end
end