fix(loader): show proper error message when trying to load a plugin that is not installed. Fixes #201. Fixes #202

lua/lazy/core/loader.lua

@@ -131,25 +131,34 @@ function M.load(plugins, reason)
   ---@cast plugins (string|LazyPlugin)[]
 
   for _, plugin in pairs(plugins) do
-    local try_load = true
-
     if type(plugin) == "string" then
-      if not Config.plugins[plugin] then
-        Util.error("Plugin " .. plugin .. " not found")
-        try_load = false
-      else
+      if Config.plugins[plugin] then
         plugin = Config.plugins[plugin]
+      else
+        Util.error("Plugin " .. plugin .. " not found")
+        plugin = nil
+      end
+    end
+    if plugin and not plugin._.loaded then
+      M._load(plugin, reason)
+    end
+  end
+end
+
+---@param plugin LazyPlugin
+---@param reason {[string]:string}
+function M._load(plugin, reason)
+  if not plugin._.installed then
+    return Util.error("Plugin " .. plugin.name .. " is not installed")
+  end
+
+  if plugin.cond ~= nil then
+    if plugin.cond == false or (type(plugin.cond) == "function" and not plugin.cond()) then
+      plugin._.cond = false
+      return
     end
   end
 
-    if try_load and plugin.cond then
-      try_load = plugin.cond == true or (type(plugin.cond) == "function" and plugin.cond()) or false
-      plugin._.cond = try_load
-    end
-
-    ---@cast plugin LazyPlugin
-
-    if try_load and not plugin._.loaded then
   ---@diagnostic disable-next-line: assign-type-mismatch
   plugin._.loaded = {}
   for k, v in pairs(reason) do
@@ -188,8 +197,6 @@ function M.load(plugins, reason)
   vim.schedule(function()
     vim.cmd("do User LazyRender")
   end)
-    end
-  end
 end
 
 --- runs plugin config