New "Open At Startup" Mechanisms

[alex-courtis]

open_on_setup.* have been deprecated in favour of self serve mechanisms: Open At Startup. Please start a Discussion if you have an questions or concerns.

The existing startup mechanisms such an open_on_setup are problematic, with recent changes resulting in many regressions #1668.

The options are nonatomic and difficult (sometimes impossible) to configure for each use case.

There are often race conditions around startup and events with vim itself and other plugins.

A new mechanisms to specify startup behaviour with more granularity is under way.

The existing mechanism will be retained if an original configuration options such as open_on_setup is specified, however the user will be notified of the new mechanism on startup and pointed to a wiki page to explain migration to the new.

Update 20230109: the new mechanism will be a set of recipes for the user to control behaviour programatically, along with the events to allow this.

Update 20230129: existing configuration will be deprecated in favour of a self serve mechanism: Open At Startup

[alex-courtis]

Draft:

on_start = {
    open = {
      always = false,
      directory = true,
      unnamed = false,
      empty = false,
      file = true,
      ignore_filetype = {
        "gitcommit"
      },
    },
    focus_tree = {
      always = true,
      unnamed = false,
      empty = false,
      file = false,
    },
  }

unnamed is a buffer with empty bufname().

empty is a buffer with a name but filereadable(bufname()) == 0. Needs a better name.

The new configuration could go in an alternate nvim-tree.on_enter to be used if the user has specified on_start.

[alex-courtis]

LunarVim must be notified prior to release so that they may refactor ignore_ft: https://github.com/LunarVim/LunarVim/blob/36c8bdee9ff59a0a63c1edfc445b5eb2886cf246/lua/lvim/core/nvimtree.lua#L9