fix(lua): preserve argument lists which are not lists

3 files changed, 30 insertions, 2 deletions

diff --git a/runtime/lua/vim/F.lua b/runtime/lua/vim/F.lua
index 09467eb8c6..1a258546a5 100644
--- a/runtime/lua/vim/F.lua
+++ b/runtime/lua/vim/F.lua
@@ -27,5 +27,14 @@ function F.nil_wrap(fn)
   end
 end
 
+--- like {...} except preserve the lenght explicitly
+function F.pack_len(...)
+  return {n=select('#', ...), ...}
+end
+
+--- like unpack() but use the length set by F.pack_len if present
+function F.unpack_len(t)
+  return unpack(t, 1, t.n)
+end
 
 return F
diff --git a/src/nvim/lua/vim.lua b/src/nvim/lua/vim.lua
index ed435439a4..801226ab7b 100644
--- a/src/nvim/lua/vim.lua
+++ b/src/nvim/lua/vim.lua
@@ -273,8 +273,8 @@ end
 ---@see |vim.in_fast_event()|
 function vim.schedule_wrap(cb)
   return (function (...)
-    local args = {...}
-    vim.schedule(function() cb(unpack(args)) end)
+    local args = vim.F.pack_len(...)
+    vim.schedule(function() cb(vim.F.unpack_len(args)) end)
   end)
 end
 
diff --git a/test/functional/lua/vim_spec.lua b/test/functional/lua/vim_spec.lua
index 4e2bed4deb..0ea914880f 100644
--- a/test/functional/lua/vim_spec.lua
+++ b/test/functional/lua/vim_spec.lua
@@ -17,6 +17,7 @@ local matches = helpers.matches
 local source = helpers.source
 local NIL = helpers.NIL
 local retry = helpers.retry
+local next_msg = helpers.next_msg
 
 before_each(clear)
 
@@ -2178,6 +2179,24 @@ describe('lua stdlib', function()
     end)
   end)
 
+  describe('vim.schedule_wrap', function()
+    it('preserves argument lists', function()
+      exec_lua [[
+        local fun = vim.schedule_wrap(function(kling, klang, klonk)
+          vim.rpcnotify(1, 'mayday_mayday', {a=kling, b=klang, c=klonk})
+        end)
+        fun("BOB", nil, "MIKE")
+      ]]
+      eq({'notification', 'mayday_mayday', {{a='BOB', c='MIKE'}}}, next_msg())
+
+      -- let's gooooo
+      exec_lua [[
+        vim.schedule_wrap(function(...) vim.rpcnotify(1, 'boogalo', select('#', ...)) end)(nil,nil,nil,nil)
+      ]]
+      eq({'notification', 'boogalo', {4}}, next_msg())
+    end)
+  end)
+
   describe('vim.api.nvim_buf_call', function()
     it('can access buf options', function()
       local buf1 = meths.get_current_buf()