fix(tui): don't try to add unsupported modifiers (#33799)

Problem:  The TUI doesn't forward a key properly when it has unsupported
          modifiers like NumLock.
Solution: Don't try to add modifiers when only unsupported modifiers are
          present.

Related #33791

(cherry picked from commit adbd33027f)

src/nvim/tui/input.c

@@ -21,6 +21,7 @@
 #include "nvim/tui/input_defs.h"
 #include "nvim/tui/termkey/driver-csi.h"
 #include "nvim/tui/termkey/termkey.h"
+#include "nvim/tui/termkey/termkey_defs.h"
 #include "nvim/tui/tui.h"
 #include "nvim/ui_client.h"
 
@@ -248,6 +249,13 @@ static size_t handle_termkey_modifiers(TermKeyKey *key, char *buf, size_t buflen
   return len;
 }
 
+enum {
+  KEYMOD_SUPER      = 1 << 3,
+  KEYMOD_META       = 1 << 5,
+  KEYMOD_RECOGNIZED = (TERMKEY_KEYMOD_SHIFT | TERMKEY_KEYMOD_ALT | TERMKEY_KEYMOD_CTRL
+                       | KEYMOD_SUPER | KEYMOD_META),
+};
+
 /// Handle modifiers not handled by libtermkey.
 /// Currently only Super ("D-") and Meta ("T-") are supported in Nvim.
 ///
@@ -256,10 +264,10 @@ static size_t handle_more_modifiers(TermKeyKey *key, char *buf, size_t buflen)
   FUNC_ATTR_WARN_UNUSED_RESULT
 {
   size_t len = 0;
-  if (key->modifiers & 8) {  // Super
+  if (key->modifiers & KEYMOD_SUPER) {
     len += (size_t)snprintf(buf + len, buflen - len, "D-");
   }
-  if (key->modifiers & 32) {  // Meta
+  if (key->modifiers & KEYMOD_META) {
     len += (size_t)snprintf(buf + len, buflen - len, "T-");
   }
   assert(len < buflen);
@@ -444,7 +452,7 @@ static void tk_getkeys(TermInput *input, bool force)
       continue;
     }
 
-    if (key.type == TERMKEY_TYPE_UNICODE && !key.modifiers) {
+    if (key.type == TERMKEY_TYPE_UNICODE && !(key.modifiers & KEYMOD_RECOGNIZED)) {
       forward_simple_utf8(input, &key);
     } else if (key.type == TERMKEY_TYPE_UNICODE
                || key.type == TERMKEY_TYPE_FUNCTION

test/functional/terminal/tui_spec.lua

@@ -440,19 +440,32 @@ describe('TUI', function()
     ]])
   end)
 
-  it('interprets <Esc>[27u as <Esc>', function()
+  it('interprets <Esc> encoded with kitty keyboard protocol', function()
     child_session:request(
       'nvim_exec2',
       [[
       nnoremap <M-;> <Nop>
       nnoremap <Esc> AESC<Esc>
+      nnoremap <C-Esc> ACtrlEsc<Esc>
+      nnoremap <D-Esc> ASuperEsc<Esc>
       nnoremap ; Asemicolon<Esc>
     ]],
       {}
     )
+    -- Works with no modifier
     feed_data('\027[27u;')
+    expect_child_buf_lines({ 'ESCsemicolon' })
+    -- Works with Ctrl modifier
+    feed_data('\027[27;5u')
+    expect_child_buf_lines({ 'ESCsemicolonCtrlEsc' })
+    -- Works with Super modifier
+    feed_data('\027[27;9u')
+    expect_child_buf_lines({ 'ESCsemicolonCtrlEscSuperEsc' })
+    -- Works with NumLock modifier (which should be the same as no modifier) #33799
+    feed_data('\027[27;129u')
+    expect_child_buf_lines({ 'ESCsemicolonCtrlEscSuperEscESC' })
     screen:expect([[
-      ESCsemicolo^n                                      |
+      ESCsemicolonCtrlEscSuperEscES^C                    |
       {4:~                                                 }|*3
       {5:[No Name] [+]                                     }|
                                                         |
@@ -461,6 +474,7 @@ describe('TUI', function()
     -- <Esc>; should be recognized as <M-;> when <M-;> is mapped
     feed_data('\027;')
     screen:expect_unchanged()
+    expect_child_buf_lines({ 'ESCsemicolonCtrlEscSuperEscESC' })
   end)
 
   it('interprets <Esc><Nul> as <M-C-Space> #17198', function()