feat(mapset): support restoring "replace_keycodes" and "desc"

src/nvim/mapping.c

@@ -428,6 +428,9 @@ static int str_to_mapargs(const char_u *strargs, bool is_unmap, MapArguments *ma
   return 0;
 }
 
+/// @param args  "rhs", "rhs_lua", "orig_rhs", "expr", "silent", "nowait", "replace_keycodes" and
+///              and "desc" fields are used.
+///              "rhs", "rhs_lua", "orig_rhs" fields are cleared if "simplified" is false.
 /// @param sid  -1 to use current_sctx
 static void map_add(buf_T *buf, mapblock_T **map_table, mapblock_T **abbr_table, const char_u *keys,
                     MapArguments *args, int noremap, int mode, bool is_abbr, scid_T sid,
@@ -2162,15 +2165,15 @@ void f_mapset(typval_T *argvars, typval_T *rettv, FunPtr fptr)
   if (tv_dict_get_number(d, "script") != 0) {
     noremap = REMAP_SCRIPT;
   }
-
+  MapArguments args = {  // TODO(zeertzjq): support restoring "callback"?
-  // TODO: support "callback" and "desc"
-  MapArguments args = {
     .rhs = (char_u *)rhs,
     .rhs_lua = LUA_NOREF,
     .orig_rhs = vim_strsave((char_u *)orig_rhs),
     .expr = tv_dict_get_number(d, "expr") != 0,
     .silent = tv_dict_get_number(d, "silent") != 0,
     .nowait = tv_dict_get_number(d, "nowait") != 0,
+    .replace_keycodes = tv_dict_get_number(d, "replace_keycodes") != 0,
+    .desc = tv_dict_get_string(d, "desc", false),
   };
   scid_T sid = (scid_T)tv_dict_get_number(d, "sid");
   linenr_T lnum = (linenr_T)tv_dict_get_number(d, "lnum");

test/functional/vimscript/map_functions_spec.lua

@@ -3,7 +3,10 @@ local helpers = require('test.functional.helpers')(after_each)
 local clear = helpers.clear
 local eq = helpers.eq
 local eval = helpers.eval
+local expect = helpers.expect
+local feed = helpers.feed
 local funcs = helpers.funcs
+local meths = helpers.meths
 local nvim = helpers.nvim
 local source = helpers.source
 local command = helpers.command
@@ -163,3 +166,32 @@ describe('maparg()', function()
     eq(acmap('e`', 'f`'), funcs.maparg(ac('e`'), 'n', 0, 1))
   end)
 end)
+
+describe('mapset()', function()
+  before_each(clear)
+
+  it('can restore mapping description from the dict returned by maparg()', function()
+    meths.set_keymap('n', 'lhs', 'rhs', {desc = 'map description'})
+    eq('\nn  lhs           rhs\n                 map description',
+       helpers.exec_capture("nmap lhs"))
+    local mapargs = funcs.maparg('lhs', 'n', false, true)
+    meths.del_keymap('n', 'lhs')
+    eq('\nNo mapping found', helpers.exec_capture("nmap lhs"))
+    funcs.mapset('n', false, mapargs)
+    eq('\nn  lhs           rhs\n                 map description',
+       helpers.exec_capture("nmap lhs"))
+  end)
+
+  it('can restore "replace_keycodes" from the dict returned by maparg()', function()
+    meths.set_keymap('i', 'foo', [['<l' .. 't>']], {expr = true, replace_keycodes = true})
+    feed('Afoo')
+    expect('<')
+    local mapargs = funcs.maparg('foo', 'i', false, true)
+    meths.set_keymap('i', 'foo', [['<l' .. 't>']], {expr = true})
+    feed('foo')
+    expect('<<lt>')
+    funcs.mapset('i', false, mapargs)
+    feed('foo')
+    expect('<<lt><')
+  end)
+end)