fix(ui): z=, tselect with async vim.ui.select

Problem:
After 55ceb31,  z= and tselect don't work if `vim.ui.select` is an async
provider (especially terminal buffers).

Solution:
Drop the `vim.wait()` approach, use an async approach.

fix #39506

runtime/lua/vim/_core/ex_cmd.lua

@@ -6,7 +6,8 @@ local uv = vim.uv
 local N_ = vim.fn.gettext
 
 --- Parsed ex command arguments for builtin commands, passed from C via `nlua_call_excmd`.
---- Inherits fields from user command args: args, bang, line1, line2, range, count, reg, smods.
+--- Inherits fields from user command args: name, args, bang, line1, line2, range, count, reg, smods.
+--- Note: For builtin commands `name` is the canonical command name.
 --- @class vim._core.ExCmdArgs : vim.api.keyset.create_user_command.command_args
 
 local M = {}

runtime/lua/vim/_core/spell.lua

@@ -1,4 +1,3 @@
-local select_blocking = require('vim._core.ui').select_blocking
 local N_ = vim.fn.gettext
 
 local M = {}
@@ -10,13 +9,15 @@ local M = {}
 --- @field altscore? integer Secondary score (only set when 'spellsuggest' contains "double" or "best").
 --- @field salscore? boolean True if the score came from sound-alike comparison (only set alongside `altscore`).
 
---- Implements `spell_suggest()` (`z=`) vim.ui.select().
+--- Implements `spell_suggest()` (`z=`) via vim.ui.select().
+---
+--- async: returns immediately, the chosen suggestion is applied later
+--- by re-running `:normal! [idx]z=` from `on_choice`.
 ---
 --- @param items vim._core.spell.Suggestion[]
 --- @param bad string The misspelled word being replaced.
---- @return integer? # Selected item (1-indexed), or nil if cancelled.
 function M.select_suggest(items, bad)
-  return select_blocking(items, {
+  vim.ui.select(items, {
     prompt = N_('Change "%s" to:'):format(bad),
     kind = 'spell',
     format_item = function(s)
@@ -29,7 +30,14 @@ function M.select_suggest(items, bad)
       end
       return ('"%s"%s%s'):format(s.word, extra, score)
     end,
-  })
+  }, function(_, idx)
+    if not idx then
+      return
+    end
+    -- Queue ":normal! [idx]z=" as user input, so the recursive spell_suggest runs via the normal
+    -- input-dispatch loop. Using vim.schedule + vim.cmd can hang bc of "Press ENTER".
+    vim.fn.feedkeys(vim.keycode(('<Cmd>normal! %dz=<CR>'):format(idx)), 'in')
+  end)
 end
 
 return M

runtime/lua/vim/_core/tag.lua

@@ -1,4 +1,3 @@
-local select_blocking = require('vim._core.ui').select_blocking
 local N_ = vim.fn.gettext
 
 local M = {}
@@ -13,31 +12,47 @@ local M = {}
 
 --- Implements `do_tag()` (`:tselect`, ambiguous `:tag`, …) via vim.ui.select().
 ---
---- @param items vim._core.tag.Match[] One per matching tag.
---- @return integer? # Selected item (1-indexed), or nil if cancelled.
-function M.select_tag(items)
+--- async: returns immediately, the chosen tag is applied later by re-running
+--- `:[mods] [idx]tag {tagname}` (or `stag`) from `on_choice`.
+---
+--- @param eap vim._core.ExCmdArgs Original :tselect/:stselect/… invocation.
+--- @param extra { items: vim._core.tag.Match[], tagname: string }
+function M.select_tag(eap, extra)
+  local items, tagname = extra.items, extra.tagname
+  -- :stag/:stselect/:stjump need a split when re-invoked.
+  local stag = eap.name:sub(1, 1) == 's'
+  -- `eap.mods` is the raw modifier string (e.g. ":vert silent").
+  local mods_str = eap.mods ~= '' and (eap.mods .. ' ') or ''
+
   local taglen = 18
   for _, m in ipairs(items) do
     taglen = math.max(taglen, vim.fn.strdisplaywidth(m.tag) + 2)
   end
 
-  return select_blocking(items, {
+  vim.ui.select(items, {
     prompt = N_('Type number and <Enter> (q or empty cancels):'),
     kind = 'tag',
     format_item = function(m)
       local marker = m.cur and '>' or ' '
       local kind = m.kind or ''
-      local extra = m.extra and (' ' .. m.extra) or ''
       return ('%s %s %-4s %-' .. taglen .. 's %s%s'):format(
         marker,
         m.pri,
         kind,
         m.tag,
         m.file,
-        extra
+        m.extra and (' ' .. m.extra) or ''
       )
     end,
-  })
+  }, function(_, idx)
+    if not idx then
+      return
+    end
+    -- Queue ":[mods] [idx](s)tag {tagname}" as user input, so the recursive do_tag runs via the
+    -- normal input-dispatch loop. Using vim.schedule + vim.cmd can hang bc of "Press ENTER".
+    local cmd = stag and 'stag' or 'tag'
+    vim.fn.feedkeys(vim.keycode(('<Cmd>%s%d%s %s<CR>'):format(mods_str, idx, cmd, tagname)), 'in')
+  end)
 end
 
 return M