vim-patch:8.1.2233: cannot get the Vim command line arguments (#12117)

Problem:    Cannot get the Vim command line arguments.
Solution:   Add v:argv. (Dmitri Vereshchagin, closes vim/vim#1322)
69bf634858

src/nvim/eval.c

@@ -230,6 +230,7 @@ static struct vimvar {
   VV(VV_ECHOSPACE,      "echospace",        VAR_NUMBER, VV_RO),
   VV(VV_EXITING,        "exiting",          VAR_NUMBER, VV_RO),
   VV(VV_LUA,            "lua",              VAR_PARTIAL, VV_RO),
+  VV(VV_ARGV,           "argv",             VAR_LIST, VV_RO),
 };
 #undef VV
 
@@ -8108,6 +8109,23 @@ void set_vim_var_dict(const VimVarIndex idx, dict_T *const val)
   }
 }
 
+/// Set the v:argv list.
+void set_argv_var(char **argv, int argc)
+{
+  list_T *l = tv_list_alloc(argc);
+  int i;
+
+  if (l == NULL) {
+    getout(1);
+  }
+  tv_list_set_lock(l, VAR_FIXED);
+  for (i = 0; i < argc; i++) {
+    tv_list_append_string(l, (const char *const)argv[i], -1);
+    TV_LIST_ITEM_TV(tv_list_last(l))->v_lock = VAR_FIXED;
+  }
+  set_vim_var_list(VV_ARGV, l);
+}
+
 /*
  * Set v:register if needed.
  */

src/nvim/eval.h

@@ -159,6 +159,7 @@ typedef enum {
     VV_ECHOSPACE,
     VV_EXITING,
     VV_LUA,
+    VV_ARGV,
 } VimVarIndex;
 
 /// All recognized msgpack types

src/nvim/main.c

@@ -269,6 +269,8 @@ int main(int argc, char **argv)
 
   early_init();
 
+  set_argv_var(argv, argc);  // set v:argv
+
   // Check if we have an interactive window.
   check_and_set_isatty(&params);
 

src/nvim/testdir/test_startup.vim

@@ -584,3 +584,12 @@ func Test_start_with_tabs()
   " clean up
   call StopVimInTerminal(buf)
 endfunc
+
+func Test_v_argv()
+  let out = system(GetVimCommand() . ' -es -V1 -X arg1 --cmd "echo v:argv" --cmd q')
+  let list = split(out, "', '")
+  call assert_match('vim', list[0])
+  let idx = index(list, 'arg1')
+  call assert_true(idx > 2)
+  call assert_equal(['arg1', '--cmd', 'echo v:argv', '--cmd', 'q'']'], list[idx:])
+endfunc