fix(lua): clear got_int when calling vim.on_key() callback (#18979)

src/nvim/lua/executor.c

@@ -1775,10 +1775,13 @@ void nlua_execute_on_key(int c)
   // [ vim, vim._on_key, buf ]
   lua_pushlstring(lstate, (const char *)buf, buf_len);
 
+  int save_got_int = got_int;
+  got_int = false;  // avoid interrupts when the key typed is Ctrl-C
   if (nlua_pcall(lstate, 1, 0)) {
     nlua_error(lstate,
                _("Error executing  vim.on_key Lua callback: %.*s"));
   }
+  got_int |= save_got_int;
 
   // [ vim ]
   lua_pop(lstate, 1);

test/functional/lua/vim_spec.lua

@@ -23,6 +23,7 @@ local mkdir_p = helpers.mkdir_p
 local rmdir = helpers.rmdir
 local write_file = helpers.write_file
 local expect_exit = helpers.expect_exit
+local poke_eventloop = helpers.poke_eventloop
 
 describe('lua stdlib', function()
   before_each(clear)
@@ -2268,6 +2269,22 @@ describe('lua stdlib', function()
 
       eq('iworld<ESC>', exec_lua[[return table.concat(keys, '')]])
     end)
+
+    it('can call vim.fn functions on Ctrl-C #17273', function()
+      exec_lua([[
+        _G.ctrl_c_cmdtype = ''
+
+        vim.on_key(function(c)
+          if c == '\3' then
+            _G.ctrl_c_cmdtype = vim.fn.getcmdtype()
+          end
+        end)
+      ]])
+      feed('/')
+      poke_eventloop()  -- This is needed because Ctrl-C flushes input
+      feed('<C-C>')
+      eq('/', exec_lua([[return _G.ctrl_c_cmdtype]]))
+    end)
   end)
 
   describe('vim.wait', function()