vim-patch:9.1.1247: fragile setup to get (preferred) keys from key_name_entry (#33102)

Problem:  fragile setup to get (preferred) keys from key_name_entry
          (after v9.1.1179)
Solution: refactor the code further, fix a bug with "pref_name" key
          entry introduced in v9.1.1180 (Yee Cheng Chin)

The optimization introduced for using bsearch() with key_name_entry
in vim/vim#16788 was fragile as it required synchronizing a non-obvious index
(e.g. IDX_KEYNAME_SWU) with the array that could be accidentally changed
by any one adding a key to it. Furthermore, the "pref_name" that was
introduced in that change was unnecessary, and in fact introduced a bug,
as we don't always want to use the canonical name.

The bug is triggered when the user triggers auto-complete using a
keycode, such as `:set <Scroll<Tab>`. The bug would end up showing two
copies of `<ScrollWheelUp>` because both entries end up using the
canonical name.

In this change, remove `pref_name`, and simply use a boolean to track
whether an entry is an alt name or not and modify logic to respect that.

Add test to make sure auto-complete works with alt names

closes: vim/vim#16987

https://github.com/vim/vim/commit/7d8e7df55190e8e4e5a66f443e4440b52edf2fdb

In Nvim there is no `enabled` field, so put `is_alt` before `name` to
reduce the size of the struct.

Co-authored-by: Yee Cheng Chin <ychin.git@gmail.com>

1 files changed, 8 insertions, 25 deletions

diff --git a/src/gen/gen_keycodes.lua b/src/gen/gen_keycodes.lua
index 6fbfb5190f..584f0a3d36 100644
--- a/src/gen/gen_keycodes.lua
+++ b/src/gen/gen_keycodes.lua
@@ -38,43 +38,26 @@ hashorder, hashfun = hashy.hashy_hash('get_special_key_code', hashorder, functio
   return 'key_names_table[' .. idx .. '].name.data'
 end, true)
 
---- @type table<string,integer>
---- Maps keys to the (after hash) indexes of the entries with preferred names.
-local key_hash_idx = {}
-
-local name_orig_idx_ = vim.deepcopy(name_orig_idx)
-for i, lower_name in ipairs(hashorder) do
-  local orig_idx = table.remove(name_orig_idx_[lower_name], 1)
-  local keycode = keycode_names[orig_idx]
-  local key = keycode[1]
-  if key_orig_idx[key] == orig_idx then
-    key_hash_idx[key] = i
-  end
-end
-assert(vim.iter(vim.tbl_values(name_orig_idx_)):all(vim.tbl_isempty))
-
 local names_tgt = assert(io.open(names_file, 'w'))
 names_tgt:write([[
 static const struct key_name_entry {
-  int key;                  ///< Special key code or ascii value
-  String name;              ///< Name of key
-  const String *pref_name;  ///< Pointer to preferred key name
-                            ///< (may be NULL or point to the name in another entry)
+  int key;      ///< Special key code or ascii value
+  bool is_alt;  ///< Is an alternative name
+  String name;  ///< Name of key
 } key_names_table[] = {]])
 
-name_orig_idx_ = vim.deepcopy(name_orig_idx)
-for i, lower_name in ipairs(hashorder) do
+local name_orig_idx_ = vim.deepcopy(name_orig_idx)
+for _, lower_name in ipairs(hashorder) do
   local orig_idx = table.remove(name_orig_idx_[lower_name], 1)
   local keycode = keycode_names[orig_idx]
   local key = keycode[1]
   local name = keycode[2]
-  local pref_idx = key_hash_idx[key]
   names_tgt:write(
-    ('\n  {%s, {"%s", %u}, %s},'):format(
+    ('\n  {%s, %s, {"%s", %u}},'):format(
       key,
+      key_orig_idx[key] == orig_idx and 'false' or 'true',
       name,
-      #name,
-      pref_idx == i and 'NULL' or ('&key_names_table[%u].name'):format(pref_idx - 1)
+      #name
     )
   )
 end