chore: migrate to classic (#2991)

* add classic, migrating nodes classes

* add mixins to classic

* typechecked optargs constructors for nodes

* typechecked optargs constructors for watcher and event

* luacheck

* typechecked optargs constructors for GitRunner

* typechecked optargs constructors for Sorter

* typechecked optargs constructors for decorators, WIP

* typechecked optargs constructors for decorators, WIP

* typechecked optargs constructors for decorators

* remove class

* replace enums with named maps

* Renderer and Builder use classic, tidy opts

* LiveFilter uses classic, tidy opts

* Filter uses classic, tidy opts

* add FilterTypes named map

* move toggles into filters

* Marks uses classic, tidy opts

* Sorter uses classic, tidy opts

* Clipboard uses classic, tidy opts

* use supers for node methods

* HighlightDisplay uses classic

* protected :new

* Watcher tidy

* Revert "use supers for node methods"

This reverts commit 9fc7a866ec.

* Watcher tidy

* format

* format

* Filters private methods

* format

* Sorter type safety

* Sorter type safety

* Sorter type safety

* Sorter type safety

* Sorter type safety

* Sorter type safety

* tidy Runner

* tidy hi-test name

lua/nvim-tree/classic.lua

@@ -0,0 +1,91 @@
+--
+-- classic
+--
+-- Copyright (c) 2014, rxi
+--
+-- This module is free software; you can redistribute it and/or modify it under
+-- the terms of the MIT license. See LICENSE for details.
+--
+-- https://github.com/rxi/classic
+--
+
+---@class (exact) Class
+---@field super Class
+---@field private implements table<Class, boolean>
+local Class = {}
+Class.__index = Class ---@diagnostic disable-line: inject-field
+
+---Default constructor
+---@protected
+function Class:new(...) --luacheck: ignore 212
+end
+
+---Extend a class, setting .super
+function Class:extend()
+  local cls = {}
+  for k, v in pairs(self) do
+    if k:find("__") == 1 then
+      cls[k] = v
+    end
+  end
+  cls.__index = cls
+  cls.super = self
+  setmetatable(cls, self)
+  return cls
+end
+
+---Implement the functions of a mixin
+---Add the mixin to .implements
+---@param mixin Class
+function Class:implement(mixin)
+  if not rawget(self, "implements") then
+    -- set on the class itself instead of parents
+    rawset(self, "implements", {})
+  end
+  self.implements[mixin] = true
+  for k, v in pairs(mixin) do
+    if self[k] == nil and type(v) == "function" then
+      self[k] = v
+    end
+  end
+end
+
+---Object is an instance of class or implements a mixin
+---@generic T
+---@param class T
+---@return boolean
+function Class:is(class)
+  local mt = getmetatable(self)
+  while mt do
+    if mt == class then
+      return true
+    end
+    if mt.implements and mt.implements[class] then
+      return true
+    end
+    mt = getmetatable(mt)
+  end
+  return false
+end
+
+---Return object if :is otherwise nil
+---@generic T
+---@param class T
+---@return T|nil
+function Class:as(class)
+  return self:is(class) and self or nil
+end
+
+---Constructor to create instance, call :new and return
+function Class:__call(...)
+  local obj = setmetatable({}, self)
+  obj:new(...)
+  return obj
+end
+
+-- avoid unused param warnings in abstract methods
+---@param ... any
+function Class:nop(...) --luacheck: ignore 212
+end
+
+return Class