feat: added support for plugin packages by lazy, rockspec and packspec

lua/lazy/pkg/packspec.lua

@@ -0,0 +1,54 @@
+local Util = require("lazy.util")
+
+---@class PackSpec
+---@field dependencies? table<string, string>
+---@field lazy? LazyPluginSpec
+---
+local M = {}
+
+M.pkg_file = "pkg.json"
+
+---@param plugin LazyPlugin
+---@return LazyPkg?
+function M.get(plugin)
+  local file = Util.norm(plugin.dir .. "/" .. M.pkg_file)
+  if not Util.file_exists(file) then
+    return
+  end
+  ---@type PackSpec
+  local pkg = Util.try(function()
+    return vim.json.decode(Util.read_file(file))
+  end, "`" .. M.pkg_file .. "` for **" .. plugin.name .. "** has errors:")
+
+  if not pkg then
+    return
+  end
+
+  ---@type LazySpec
+  local ret = {}
+  if pkg.dependencies then
+    for url, version in pairs(pkg.dependencies) do
+      -- HACK: Add `.git` to github urls
+      if url:find("github") and not url:match("%.git$") then
+        url = url .. ".git"
+      end
+      ret[#ret + 1] = { url = url, version = version }
+    end
+  end
+  local p = pkg.lazy
+  if p then
+    p.url = p.url or plugin.url
+    p.dir = p.dir or plugin.dir
+    ret[#ret + 1] = p
+  end
+  if pkg.lazy then
+    ret[#ret + 1] = pkg.lazy
+  end
+  return {
+    source = "lazy",
+    file = M.pkg_file,
+    spec = ret,
+  }
+end
+
+return M