feat(plugin): added support for virtual plugins. Closes #1836

Author: folke

lua/lazy/core/loader.lua

@@ -341,7 +341,9 @@ function M._load(plugin, reason, opts)
   Util.track({ plugin = plugin.name, start = reason.start })
   Handler.disable(plugin)
 
-  M.add_to_rtp(plugin)
+  if not plugin.virtual then
+    M.add_to_rtp(plugin)
+  end
 
   if plugin._.pkg and plugin._.pkg.source == "rockspec" then
     M.add_to_luapath(plugin)
@@ -353,7 +355,9 @@ function M._load(plugin, reason, opts)
     end, "Failed to load deps for " .. plugin.name)
   end
 
-  M.packadd(plugin.dir)
+  if not plugin.virtual then
+    M.packadd(plugin.dir)
+  end
   if plugin.config or plugin.opts then
     M.config(plugin)
   end

lua/lazy/core/meta.lua

@@ -213,6 +213,8 @@ function M:_rebuild(name)
   plugin.dir = super.dir
   if plugin.dir then
     plugin.dir = Util.norm(plugin.dir)
+  elseif super.virtual then
+    plugin.dir = Util.norm("/dev/null/" .. plugin.name)
   else
     if plugin.dev == nil and plugin.url then
       for _, pattern in ipairs(Config.options.dev.patterns) do

lua/lazy/core/plugin.lua

@@ -237,12 +237,14 @@ function M.update_state()
         or plugin.cmd
       plugin.lazy = lazy and true or false
     end
-    if plugin.dir:find(Config.options.root, 1, true) == 1 then
+    if plugin.virtual then
+      plugin._.is_local = true
+      plugin._.installed = true -- local plugins are managed by the user
+    elseif plugin.dir:find(Config.options.root, 1, true) == 1 then
       plugin._.installed = installed[plugin.name] ~= nil
       installed[plugin.name] = nil
     else
       plugin._.is_local = true
-      plugin._.installed = true -- local plugins are managed by the user
       plugin._.installed = vim.fn.isdirectory(plugin.dir) == 1
     end
   end

lua/lazy/core/util.lua

@@ -270,7 +270,7 @@ function M.get_unloaded_rtp(modname, opts)
   local Config = require("lazy.core.config")
   if Config.spec then
     for _, plugin in pairs(Config.spec.plugins) do
-      if not (plugin._.loaded or plugin.module == false) then
+      if not (plugin._.loaded or plugin.module == false or plugin.virtual) then
         if norm == M.normname(plugin.name) then
           table.insert(rtp, 1, plugin.dir)
         else

lua/lazy/types.lua

@@ -60,6 +60,7 @@
 ---@field priority? number Only useful for lazy=false plugins to force loading certain plugins first. Default priority is 50
 ---@field dev? boolean If set, then link to the respective folder under your ~/projects
 ---@field rocks? string[]
+---@field virtual? boolean virtual plugins won't be installed or added to the rtp.
 
 ---@class LazyPlugin: LazyPluginBase,LazyPluginHandlers,LazyPluginHooks,LazyPluginRef
 ---@field dependencies? string[]