vim-patch:8.2.3888: the argument list may contain duplicates (#19795)

Problem:    The argument list may contain duplicates.
Solution:   Add the :argdedeupe command. (Nir Lichtman, closes vim/vim#6235)
73a024209c

Use latest index.txt :argdedupe doc from Vim.

src/nvim/arglist.c

@@ -620,6 +620,29 @@ void ex_next(exarg_T *eap)
   }
 }
 
+/// ":argdedupe"
+void ex_argdedupe(exarg_T *eap FUNC_ATTR_UNUSED)
+{
+  for (int i = 0; i < ARGCOUNT; i++) {
+    for (int j = i + 1; j < ARGCOUNT; j++) {
+      if (FNAMECMP(ARGLIST[i].ae_fname, ARGLIST[j].ae_fname) == 0) {
+        xfree(ARGLIST[j].ae_fname);
+        memmove(ARGLIST + j, ARGLIST + j + 1,
+                (size_t)(ARGCOUNT - j - 1) * sizeof(aentry_T));
+        ARGCOUNT--;
+
+        if (curwin->w_arg_idx == j) {
+          curwin->w_arg_idx = i;
+        } else if (curwin->w_arg_idx > j) {
+          curwin->w_arg_idx--;
+        }
+
+        j--;
+      }
+    }
+  }
+}
+
 /// ":argedit"
 void ex_argedit(exarg_T *eap)
 {

src/nvim/ex_cmds.lua

@@ -106,6 +106,12 @@ module.cmds = {
     addr_type='ADDR_ARGUMENTS',
     func='ex_listdo',
   },
+  {
+    command='argdedupe',
+    flags=TRLBAR,
+    addr_type='ADDR_NONE',
+    func='ex_argdedupe',
+  },
   {
     command='argedit',
     flags=bit.bor(BANG, NEEDARG, RANGE, ZEROR, FILES, CMDARG, ARGOPT, TRLBAR),

src/nvim/testdir/test_arglist.vim

@@ -412,6 +412,35 @@ func Test_argedit()
   bw! x
 endfunc
 
+" Test for the :argdedupe command
+func Test_argdedupe()
+  call Reset_arglist()
+  argdedupe
+  call assert_equal([], argv())
+  args a a a aa b b a b aa
+  argdedupe
+  call assert_equal(['a', 'aa', 'b'], argv())
+  args a b c
+  argdedupe
+  call assert_equal(['a', 'b', 'c'], argv())
+  args a
+  argdedupe
+  call assert_equal(['a'], argv())
+  args a A b B
+  argdedupe
+  if has('fname_case')
+    call assert_equal(['a', 'A', 'b', 'B'], argv())
+  else
+    call assert_equal(['a', 'b'], argv())
+  endif
+  args a b a c a b
+  last
+  argdedupe
+  next
+  call assert_equal('c', expand('%:t'))
+  %argd
+endfunc
+
 " Test for the :argdelete command
 func Test_argdelete()
   call Reset_arglist()