Reaper: delete empty tracks that nothing depends on

Delete_Empty_Tracks_No_Dependencies.lua

-- Delete tracks that are empty and have no dependencies.
-- Skips tracks that:
--   * contain media items
--   * are folder parents (would orphan children)
--   * receive sends from other tracks
--   * have any visible envelope with points

local r = reaper

local function track_has_envelope_points(track)
  local env_count = r.CountTrackEnvelopes(track)
  for i = 0, env_count - 1 do
    local env = r.GetTrackEnvelope(track, i)
    if r.CountEnvelopePoints(env) > 0 then return true end
  end
  return false
end

local function track_is_deletable(track)
  if r.CountTrackMediaItems(track) > 0 then return false end
  if r.GetMediaTrackInfo_Value(track, "I_FOLDERDEPTH") == 1 then return false end
  if r.GetTrackNumSends(track, -1) > 0 then return false end
  if track_has_envelope_points(track) then return false end
  return true
end

r.Undo_BeginBlock()
r.PreventUIRefresh(1)

local deleted = 0
local total = r.CountTracks(0)
for i = total - 1, 0, -1 do
  local track = r.GetTrack(0, i)
  if track and track_is_deletable(track) then
    r.DeleteTrack(track)
    deleted = deleted + 1
  end
end

r.PreventUIRefresh(-1)
r.TrackList_AdjustWindows(false)
r.UpdateArrange()
r.Undo_EndBlock("Delete empty tracks with no dependencies", -1)

r.ShowMessageBox(("Deleted %d empty track(s)."):format(deleted), "Delete Empty Tracks", 0)