vim-patch:9.1.1166: command-line auto-completion hard with wildmenu

Problem:  command-line auto-completion hard with wildmenu
Solution: implement "noselect" wildoption value (Girish Palya)

When `noselect` is present in `wildmode` and 'wildmenu' is enabled, the
completion menu appears without pre-selecting the first item.

This change makes it easier to implement command-line auto-completion,
where the menu dynamically appears as characters are typed, and `<Tab>`
can be used to manually select an item. This can be achieved by
leveraging the `CmdlineChanged` event to insert `wildchar(m)`,
triggering completion menu.

Without this change, auto-completion using the 'wildmenu' mechanism is
not feasible, as it automatically inserts the first match, preventing
dynamic selection.

The following Vimscript snippet demonstrates how to configure
auto-completion using `noselect`:

```vim
vim9script
set wim=noselect:lastused,full wop=pum wcm=<C-@> wmnu
autocmd CmdlineChanged : timer_start(0, function(CmdComplete, [getcmdline()]))

def CmdComplete(cur_cmdline: string, timer: number)
  var [cmdline, curpos] = [getcmdline(), getcmdpos()]
  if cur_cmdline ==# cmdline  # Avoid completing each character in keymaps and pasted text
    && !pumvisible() && curpos == cmdline->len() + 1

    if cmdline[curpos - 2] =~ '[\w*/:]'  # Reduce noise by completing only selected characters
      feedkeys("\<C-@>", "ti")
      set eventignore+=CmdlineChanged  # Suppress redundant completion attempts
      timer_start(0, (_) => {
        getcmdline()->substitute('\%x00$', '', '')->setcmdline()  # Remove <C-@> if no completion items exist
        set eventignore-=CmdlineChanged
      })
    endif
  endif
enddef
```

fixes: vim/vim#16551
closes: vim/vim#16759

https://github.com/vim/vim/commit/2bacc3e5fb3569e0fd98e129cb1e422ca18b80a6

Cherry-pick Wildmode_Tests() change from patch 9.0.0418.

Co-authored-by: Girish Palya <girishji@gmail.com>
Signed-off-by: Tomas Slusny <slusnucky@gmail.com>

1 files changed, 2 insertions, 2 deletions

diff --git a/src/nvim/cmdexpand.c b/src/nvim/cmdexpand.c
index 33ccc834d2..fcfeda5482 100644
--- a/src/nvim/cmdexpand.c
+++ b/src/nvim/cmdexpand.c
@@ -288,7 +288,7 @@ int nextwild(expand_T *xp, int type, int options, bool escape)
       p1 = addstar(xp->xp_pattern, xp->xp_pattern_len, xp->xp_context);
     }
     // Translate string into pattern and expand it.
-    const int use_options = (options
+    const int use_options = ((options & ~WILD_KEEP_SOLE_ITEM)
                              | WILD_HOME_REPLACE
                              | WILD_ADD_SLASH
                              | WILD_SILENT
@@ -339,7 +339,7 @@ int nextwild(expand_T *xp, int type, int options, bool escape)
 
   if (xp->xp_numfiles <= 0 && p2 == NULL) {
     beep_flush();
-  } else if (xp->xp_numfiles == 1) {
+  } else if (xp->xp_numfiles == 1 && !(options & WILD_KEEP_SOLE_ITEM)) {
     // free expanded pattern
     ExpandOne(xp, NULL, NULL, 0, WILD_FREE);
   }