Merge pull request #27874 from luukvbaal/funcerr

fix(messages)!: vim.ui_attach message callbacks are unsafe

runtime/doc/lua.txt

@@ -1083,6 +1083,10 @@ vim.ui_attach({ns}, {options}, {callback})                   *vim.ui_attach()*
     |ui-popupmenu| and the sections below for event format for respective
     events.
 
+    Callbacks for `msg_show` events are executed in |api-fast| context.
+
+    Excessive errors inside the callback will result in forced detachment.
+
     WARNING: This api is considered experimental. Usability will vary for
     different screen elements. In particular `ext_messages` behavior is
     subject to further changes and usability improvements. This is expected to

runtime/doc/news.txt

@@ -72,7 +72,8 @@ EDITOR
 
 EVENTS
 
-• TODO
+• |vim.ui_attach()| callbacks for |ui-messages| `msg_show` events are executed in
+  |api-fast| context.
 
 LSP
 

runtime/lua/vim/_meta/builtin.lua

@@ -233,6 +233,10 @@ function vim.wait(time, callback, interval, fast_only) end
 --- {callback} receives event name plus additional parameters. See |ui-popupmenu|
 --- and the sections below for event format for respective events.
 ---
+--- Callbacks for `msg_show` events are executed in |api-fast| context.
+---
+--- Excessive errors inside the callback will result in forced detachment.
+---
 --- WARNING: This api is considered experimental.  Usability will vary for
 --- different screen elements. In particular `ext_messages` behavior is subject
 --- to further changes and usability improvements.  This is expected to be

src/nvim/api/ui_events.in.h

@@ -159,7 +159,7 @@ void wildmenu_hide(void)
   FUNC_API_SINCE(3) FUNC_API_REMOTE_ONLY;
 
 void msg_show(String kind, Array content, Boolean replace_last)
-  FUNC_API_SINCE(6) FUNC_API_REMOTE_ONLY;
+  FUNC_API_SINCE(6) FUNC_API_FAST FUNC_API_REMOTE_ONLY;
 void msg_clear(void)
   FUNC_API_SINCE(6) FUNC_API_REMOTE_ONLY;
 void msg_showcmd(Array content)

src/nvim/api/vim.c

@@ -594,10 +594,12 @@ ArrayOf(String) nvim_get_runtime_file(String name, Boolean all, Arena *arena, Er
   kvi_init(cookie.rv);
 
   int flags = DIP_DIRFILE | (all ? DIP_ALL : 0);
+  TryState tstate;
+
+  try_enter(&tstate);
+  do_in_runtimepath((name.size ? name.data : ""), flags, find_runtime_cb, &cookie);
+  vim_ignored = try_leave(&tstate, err);
 
-  TRY_WRAP(err, {
-    do_in_runtimepath((name.size ? name.data : ""), flags, find_runtime_cb, &cookie);
-  });
   return arena_take_arraybuilder(arena, &cookie.rv);
 }
 

src/nvim/errors.h

@@ -151,7 +151,7 @@ EXTERN const char e_auabort[] INIT(= N_("E855: Autocommands caused command to ab
 
 EXTERN const char e_api_error[] INIT(= N_("E5555: API call: %s"));
 
-EXTERN const char e_luv_api_disabled[] INIT(= N_("E5560: %s must not be called in a lua loop callback"));
+EXTERN const char e_fast_api_disabled[] INIT(= N_("E5560: %s must not be called in a fast event context"));
 
 EXTERN const char e_floatonly[] INIT(= N_("E5601: Cannot close window, only floating window would remain"));
 EXTERN const char e_floatexchange[] INIT(= N_("E5602: Cannot exchange or rotate float"));

src/nvim/eval.c

@@ -8616,7 +8616,7 @@ bool eval_has_provider(const char *feat, bool throw_if_fast)
   }
 
   if (throw_if_fast && !nlua_is_deferred_safe()) {
-    semsg(e_luv_api_disabled, "Vimscript function");
+    semsg(e_fast_api_disabled, "Vimscript function");
     return false;
   }
 

src/nvim/generators/gen_api_dispatch.lua

@@ -750,7 +750,7 @@ local function process_function(fn)
     write_shifted_output(
       [[
     if (!nlua_is_deferred_safe()) {
-      return luaL_error(lstate, e_luv_api_disabled, "%s");
+      return luaL_error(lstate, e_fast_api_disabled, "%s");
     }
     ]],
       fn.name

src/nvim/generators/gen_api_ui_events.lua

@@ -136,8 +136,8 @@ for i = 1, #events do
       call_output:write('  }\n')
       call_output:write('  entered = true;\n')
       write_arglist(call_output, ev)
-      call_output:write('  ui_call_event("' .. ev.name .. '", ' .. args .. ');\n')
+      call_output:write(('  ui_call_event("%s", %s, %s)'):format(ev.name, tostring(ev.fast), args))
-      call_output:write('  entered = false;\n')
+      call_output:write(';\n  entered = false;\n')
     elseif ev.compositor_impl then
       call_output:write('  ui_comp_' .. ev.name)
       write_signature(call_output, ev, '', true)

src/nvim/lua/executor.c

@@ -187,7 +187,7 @@ static void nlua_luv_error_event(void **argv)
   msg_ext_set_kind("lua_error");
   switch (type) {
   case kCallback:
-    semsg_multiline("Error executing luv callback:\n%s", error);
+    semsg_multiline("Error executing callback:\n%s", error);
     break;
   case kThread:
     semsg_multiline("Error in luv thread:\n%s", error);
@@ -201,13 +201,13 @@ static void nlua_luv_error_event(void **argv)
   xfree(error);
 }
 
-static int nlua_luv_cfpcall(lua_State *lstate, int nargs, int nresult, int flags)
+/// Execute callback in "fast" context. Used for luv and some vim.ui_event
+/// callbacks where using the API directly is not safe.
+static int nlua_fast_cfpcall(lua_State *lstate, int nargs, int nresult, int flags)
   FUNC_ATTR_NONNULL_ALL
 {
   int retval;
 
-  // luv callbacks might be executed at any os_breakcheck/line_breakcheck
-  // call, so using the API directly here is not safe.
   in_fast_callback++;
 
   int top = lua_gettop(lstate);
@@ -366,11 +366,13 @@ static int nlua_init_argv(lua_State *const L, char **argv, int argc, int lua_arg
 static void nlua_schedule_event(void **argv)
 {
   LuaRef cb = (LuaRef)(ptrdiff_t)argv[0];
+  uint32_t ns_id = (uint32_t)(ptrdiff_t)argv[1];
   lua_State *const lstate = global_lstate;
   nlua_pushref(lstate, cb);
   nlua_unref_global(lstate, cb);
   if (nlua_pcall(lstate, 0, 0)) {
     nlua_error(lstate, _("Error executing vim.schedule lua callback: %.*s"));
+    ui_remove_cb(ns_id, true);
   }
 }
 
@@ -392,8 +394,9 @@ static int nlua_schedule(lua_State *const lstate)
   }
 
   LuaRef cb = nlua_ref_global(lstate, 1);
-
+  // Pass along UI event handler to disable on error.
-  multiqueue_put(main_loop.events, nlua_schedule_event, (void *)(ptrdiff_t)cb);
+  multiqueue_put(main_loop.events, nlua_schedule_event, (void *)(ptrdiff_t)cb,
+                 (void *)(ptrdiff_t)ui_event_ns_id);
   return 0;
 }
 
@@ -425,7 +428,7 @@ static int nlua_wait(lua_State *lstate)
   FUNC_ATTR_NONNULL_ALL
 {
   if (in_fast_callback) {
-    return luaL_error(lstate, e_luv_api_disabled, "vim.wait");
+    return luaL_error(lstate, e_fast_api_disabled, "vim.wait");
   }
 
   intptr_t timeout = luaL_checkinteger(lstate, 1);
@@ -598,7 +601,7 @@ static void nlua_common_vim_init(lua_State *lstate, bool is_thread, bool is_stan
     luv_set_cthread(lstate, nlua_luv_thread_cfcpcall);
   } else {
     luv_set_loop(lstate, &main_loop.uv);
-    luv_set_callback(lstate, nlua_luv_cfpcall);
+    luv_set_callback(lstate, nlua_fast_cfpcall);
   }
   luaopen_luv(lstate);
   lua_pushvalue(lstate, -1);
@@ -724,7 +727,7 @@ static int nlua_ui_detach(lua_State *lstate)
     return luaL_error(lstate, "invalid ns_id");
   }
 
-  ui_remove_cb(ns_id);
+  ui_remove_cb(ns_id, false);
   return 0;
 }
 
@@ -1174,7 +1177,7 @@ int nlua_call(lua_State *lstate)
   size_t name_len;
   const char *name = luaL_checklstring(lstate, 1, &name_len);
   if (!nlua_is_deferred_safe() && !viml_func_is_fast(name)) {
-    return luaL_error(lstate, e_luv_api_disabled, "Vimscript function");
+    return luaL_error(lstate, e_fast_api_disabled, "Vimscript function");
   }
 
   int nargs = lua_gettop(lstate) - 1;
@@ -1231,7 +1234,7 @@ free_vim_args:
 static int nlua_rpcrequest(lua_State *lstate)
 {
   if (!nlua_is_deferred_safe()) {
-    return luaL_error(lstate, e_luv_api_disabled, "rpcrequest");
+    return luaL_error(lstate, e_fast_api_disabled, "rpcrequest");
   }
   return nlua_rpc(lstate, true);
 }
@@ -1593,6 +1596,12 @@ bool nlua_ref_is_function(LuaRef ref)
 /// @return        Return value of function, as per mode
 Object nlua_call_ref(LuaRef ref, const char *name, Array args, LuaRetMode mode, Arena *arena,
                      Error *err)
+{
+  return nlua_call_ref_ctx(false, ref, name, args, mode, arena, err);
+}
+
+Object nlua_call_ref_ctx(bool fast, LuaRef ref, const char *name, Array args, LuaRetMode mode,
+                         Arena *arena, Error *err)
 {
   lua_State *const lstate = global_lstate;
   nlua_pushref(lstate, ref);
@@ -1605,7 +1614,13 @@ Object nlua_call_ref(LuaRef ref, const char *name, Array args, LuaRetMode mode,
     nlua_push_Object(lstate, &args.items[i], 0);
   }
 
-  if (nlua_pcall(lstate, nargs, 1)) {
+  if (fast) {
+    if (nlua_fast_cfpcall(lstate, nargs, 1, -1) < 0) {
+      // error is already scheduled, set anyways to convey failure.
+      api_set_error(err, kErrorTypeException, "fast context failure");
+    }
+    return NIL;
+  } else if (nlua_pcall(lstate, nargs, 1)) {
     // if err is passed, the caller will deal with the error.
     if (err) {
       size_t len;

src/nvim/ui.c

@@ -44,6 +44,7 @@
 
 typedef struct {
   LuaRef cb;
+  uint8_t errors;
   bool ext_widgets[kUIGlobalCount];
 } UIEventCallback;
 
@@ -212,21 +213,20 @@ void ui_refresh(void)
   cursor_row = cursor_col = 0;
   pending_cursor_update = true;
 
+  bool had_message = ui_ext[kUIMessages];
   for (UIExtension i = 0; (int)i < kUIExtCount; i++) {
+    ui_ext[i] = ext_widgets[i] | ui_cb_ext[i];
     if (i < kUIGlobalCount) {
-      ext_widgets[i] |= ui_cb_ext[i];
+      ui_call_option_set(cstr_as_string(ui_ext_names[i]), BOOLEAN_OBJ(ui_ext[i]));
     }
-    // Set 'cmdheight' to zero for all tabpages when ext_messages becomes active.
+  }
-    if (i == kUIMessages && !ui_ext[i] && ext_widgets[i]) {
+
-      set_option_value(kOptCmdheight, NUMBER_OPTVAL(0), 0);
+  // Reset 'cmdheight' for all tabpages when ext_messages toggles.
-      command_height();
+  if (had_message != ui_ext[kUIMessages]) {
-      FOR_ALL_TABS(tp) {
+    set_option_value(kOptCmdheight, NUMBER_OPTVAL(had_message), 0);
-        tp->tp_ch_used = 0;
+    command_height();
-      }
+    FOR_ALL_TABS(tp) {
-    }
+      tp->tp_ch_used = had_message;
-    ui_ext[i] = ext_widgets[i];
-    if (i < kUIGlobalCount) {
-      ui_call_option_set(cstr_as_string(ui_ext_names[i]), BOOLEAN_OBJ(ext_widgets[i]));
     }
   }
 
@@ -713,13 +713,15 @@ void ui_grid_resize(handle_T grid_handle, int width, int height, Error *err)
   }
 }
 
-void ui_call_event(char *name, Array args)
+void ui_call_event(char *name, bool fast, Array args)
 {
-  UIEventCallback *event_cb;
   bool handled = false;
-  map_foreach_value(&ui_event_cbs, event_cb, {
+  UIEventCallback *event_cb;
+  map_foreach(&ui_event_cbs, ui_event_ns_id, event_cb, {
     Error err = ERROR_INIT;
-    Object res = nlua_call_ref(event_cb->cb, name, args, kRetNilBool, NULL, &err);
+    uint32_t ns_id = ui_event_ns_id;
+    Object res = nlua_call_ref_ctx(fast, event_cb->cb, name, args, kRetNilBool, NULL, &err);
+    ui_event_ns_id = 0;
     // TODO(bfredl/luukvbaal): should this be documented or reconsidered?
     // Why does truthy return from Lua callback mean remote UI should not receive
     // the event.
@@ -728,6 +730,7 @@ void ui_call_event(char *name, Array args)
     }
     if (ERROR_SET(&err)) {
       ELOG("Error executing UI event callback: %s", err.msg);
+      ui_remove_cb(ns_id, true);
     }
     api_clear_error(&err);
   })
@@ -780,12 +783,16 @@ void ui_add_cb(uint32_t ns_id, LuaRef cb, bool *ext_widgets)
   ui_refresh();
 }
 
-void ui_remove_cb(uint32_t ns_id)
+void ui_remove_cb(uint32_t ns_id, bool checkerr)
 {
-  if (map_has(uint32_t, &ui_event_cbs, ns_id)) {
+  UIEventCallback *item = pmap_get(uint32_t)(&ui_event_cbs, ns_id);
-    UIEventCallback *item = pmap_del(uint32_t)(&ui_event_cbs, ns_id, NULL);
+  if (item && (!checkerr || ++item->errors > 10)) {
+    pmap_del(uint32_t)(&ui_event_cbs, ns_id, NULL);
     free_ui_event_callback(item);
+    ui_cb_update_ext();
+    ui_refresh();
+    if (checkerr) {
+      msg_schedule_semsg("Excessive errors in vim.ui_attach() callback from ns: %d.", ns_id);
+    }
   }
-  ui_cb_update_ext();
-  ui_refresh();
 }

src/nvim/ui.h

@@ -18,4 +18,6 @@ EXTERN Array noargs INIT(= ARRAY_DICT_INIT);
 #endif
 // uncrustify:on
 
-EXTERN MultiQueue *resize_events;
+// vim.ui_attach() namespace of currently executed callback.
+EXTERN uint32_t ui_event_ns_id INIT( = 0);
+EXTERN MultiQueue *resize_events INIT( = NULL);

test/functional/api/extmark_spec.lua

@@ -757,7 +757,7 @@ describe('API/extmarks', function()
         {
           Ïf (!nlua_is_deferred_safe(lstate)) {
         	// strictly not allowed
-            Яetörn luaL_error(lstate, e_luv_api_disabled, "rpcrequest");
+            Яetörn luaL_error(lstate, e_fast_api_disabled, "rpcrequest");
           }
           return nlua_rpc(lstate, true);
         }]])

test/functional/lua/loop_spec.lua

@@ -87,9 +87,9 @@ describe('vim.uv', function()
     screen:expect([[
                                                         |
       {2:                                                  }|
-      {3:Error executing luv callback:}                     |
+      {3:Error executing callback:}                         |
       {3:[string "<nvim>"]:5: E5560: nvim_set_var must not }|
-      {3:be called in a lua loop callback}                  |
+      {3:be called in a fast event context}                 |
       {3:stack traceback:}                                  |
       {3:        [C]: in function 'nvim_set_var'}           |
       {3:        [string "<nvim>"]:5: in function <[string }|

test/functional/lua/ui_event_spec.lua

@@ -32,15 +32,6 @@ describe('vim.ui_attach', function()
     ]]
 
     screen = Screen.new(40, 5)
-    screen:set_default_attr_ids({
-      [1] = { bold = true, foreground = Screen.colors.Blue1 },
-      [2] = { bold = true },
-      [3] = { background = Screen.colors.Grey },
-      [4] = { background = Screen.colors.LightMagenta },
-      [5] = { reverse = true },
-      [6] = { reverse = true, bold = true },
-      [7] = { background = Screen.colors.Yellow1 },
-    })
   end)
 
   local function expect_events(expected)
@@ -55,7 +46,7 @@ describe('vim.ui_attach', function()
       grid = [[
       fo^                                      |
       {1:~                                       }|*3
-      {2:-- INSERT --}                            |
+      {5:-- INSERT --}                            |
     ]],
     }
 
@@ -64,7 +55,7 @@ describe('vim.ui_attach', function()
       grid = [[
       food^                                    |
       {1:~                                       }|*3
-      {2:-- INSERT --}                            |
+      {5:-- INSERT --}                            |
     ]],
     }
     expect_events {
@@ -83,7 +74,7 @@ describe('vim.ui_attach', function()
       grid = [[
       foobar^                                  |
       {1:~                                       }|*3
-      {2:-- INSERT --}                            |
+      {5:-- INSERT --}                            |
     ]],
     }
     expect_events {
@@ -105,10 +96,10 @@ describe('vim.ui_attach', function()
     screen:expect {
       grid = [[
       food^                                    |
-      {3:food           }{1:                         }|
+      {12:food           }{1:                         }|
       {4:foobar         }{1:                         }|
       {4:foo            }{1:                         }|
-      {2:-- INSERT --}                            |
+      {5:-- INSERT --}                            |
     ]],
     }
     expect_events {}
@@ -180,12 +171,17 @@ describe('vim.ui_attach', function()
     exec_lua([[
       _G.cmdline = 0
       vim.ui_attach(ns, { ext_messages = true }, function(ev)
-        vim.cmd.redraw()
+        if ev == 'msg_show' then
+          vim.schedule(function() vim.cmd.redraw() end)
+        else
+          vim.cmd.redraw()
+        end
         _G.cmdline = _G.cmdline + (ev == 'cmdline_show' and 1 or 0)
       end
     )]])
     feed(':')
-    eq(1, exec_lua('return _G.cmdline'))
+    n.assert_alive()
+    eq(2, exec_lua('return _G.cmdline'))
     n.assert_alive()
     feed('version<CR><CR>v<Esc>')
     n.assert_alive()
@@ -211,9 +207,9 @@ describe('vim.ui_attach', function()
     screen:expect({
       grid = [[
         cmdline                                 |
-        {5:cmdline [+]                             }|
+        {2:cmdline [+]                             }|
         fooba^r                                  |
-        {6:[No Name] [+]                           }|
+        {3:[No Name] [+]                           }|
                                                 |
       ]],
     })
@@ -222,9 +218,9 @@ describe('vim.ui_attach', function()
     screen:expect({
       grid = [[
         foo                                     |
-        {5:cmdline [+]                             }|
+        {2:cmdline [+]                             }|
-        {5:foo}ba^r                                  |
+        {2:foo}ba^r                                  |
-        {6:[No Name] [+]                           }|
+        {3:[No Name] [+]                           }|
                                                 |
       ]],
     })
@@ -233,13 +229,124 @@ describe('vim.ui_attach', function()
     screen:expect({
       grid = [[
         %s/bar/baz                              |
-        {5:cmdline [+]                             }|
+        {2:cmdline [+]                             }|
-        foo{7:ba^z}                                  |
+        foo{10:ba^z}                                  |
-        {6:[No Name] [+]                           }|
+        {3:[No Name] [+]                           }|
                                                 |
       ]],
     })
   end)
+
+  it('aborts :function on error with ext_messages', function()
+    exec_lua([[
+    vim.ui_attach(ns, { ext_messages = true }, function(event, _, content)
+      if event == "msg_show" then
+        -- "fast-api" does not prevent aborting :function
+        vim.api.nvim_get_runtime_file("foo", false)
+        -- non-"fast-api" is not allowed in msg_show callback and should be scheduled
+        local _, err = pcall(vim.api.nvim_buf_set_lines, 0, -2, -1, false, { content[1][2] })
+        vim.schedule(function()
+          vim.api.nvim_buf_set_lines(0, -2, -1, false, { content[1][2], err })
+        end)
+      end
+    end)
+    ]])
+    feed(':func Foo()<cr>bar<cr>endf<cr>:func Foo()<cr>')
+    screen:expect({
+      grid = [[
+        ^E122: Function Foo already exists, add !|
+         to replace it                          |
+        E5560: nvim_buf_set_lines must not be ca|
+        lled in a fast event context            |
+        {1:~                                       }|
+      ]],
+      messages = {
+        {
+          content = { { 'E122: Function Foo already exists, add ! to replace it', 9, 7 } },
+          kind = 'emsg',
+        },
+      },
+    })
+  end)
+
+  it('detaches after excessive errors', function()
+    screen:add_extra_attr_ids({ [100] = { bold = true, foreground = Screen.colors.SeaGreen } })
+    exec_lua([[
+      vim.ui_attach(vim.api.nvim_create_namespace(''), { ext_messages = true }, function()
+        vim.api.nvim_buf_set_lines(0, -2, -1, false, { err[1] })
+      end)
+    ]])
+    screen:expect({
+      grid = [[
+        ^                                        |
+        {1:~                                       }|*4
+      ]],
+    })
+    feed('ifoo')
+    screen:expect({
+      grid = [[
+        foo^                                     |
+        {1:~                                       }|*4
+      ]],
+      showmode = { { '-- INSERT --', 5, 12 } },
+    })
+    feed('<esc>:1mes clear<cr>:mes<cr>')
+    screen:expect({
+      grid = [[
+        foo                                     |
+        {3:                                        }|
+        {9:Excessive errors in vim.ui_attach() call}|
+        {9:back from ns: 2.}                        |
+        {100:Press ENTER or type command to continue}^ |
+      ]],
+    })
+    feed('<cr>')
+    -- Also when scheduled
+    exec_lua([[
+      vim.ui_attach(vim.api.nvim_create_namespace(''), { ext_messages = true }, function()
+        vim.schedule(function() vim.api.nvim_buf_set_lines(0, -2, -1, false, { err[1] }) end)
+      end)
+    ]])
+    screen:expect({
+      any = 'fo^o',
+      messages = {
+        {
+          content = {
+            {
+              'Error executing vim.schedule lua callback: [string "<nvim>"]:2: attempt to index global \'err\' (a nil value)\nstack traceback:\n\t[string "<nvim>"]:2: in function <[string "<nvim>"]:2>',
+              9,
+              7,
+            },
+          },
+          kind = 'lua_error',
+        },
+        {
+          content = {
+            {
+              'Error executing vim.schedule lua callback: [string "<nvim>"]:2: attempt to index global \'err\' (a nil value)\nstack traceback:\n\t[string "<nvim>"]:2: in function <[string "<nvim>"]:2>',
+              9,
+              7,
+            },
+          },
+          kind = 'lua_error',
+        },
+        {
+          content = { { 'Press ENTER or type command to continue', 100, 19 } },
+          kind = 'return_prompt',
+        },
+      },
+    })
+    feed('<esc>:1mes clear<cr>:mes<cr>')
+    screen:expect({
+      grid = [[
+        foo                                     |
+        {3:                                        }|
+        {9:Excessive errors in vim.ui_attach() call}|
+        {9:back from ns: 3.}                        |
+        {100:Press ENTER or type command to continue}^ |
+      ]],
+    })
+  end)
 end)
 
 describe('vim.ui_attach', function()

test/functional/lua/vim_spec.lua

@@ -1414,7 +1414,7 @@ describe('lua stdlib', function()
     screen:expect {
       grid = [[
       {9:[string "<nvim>"]:6: E5560: rpcrequest must not be}|
-      {9: called in a lua loop callback}                    |
+      {9: called in a fast event context}                   |
       {9:stack traceback:}                                  |
       {9:        [C]: in function 'rpcrequest'}             |
       {9:        [string "<nvim>"]:6: in function <[string }|
@@ -3783,7 +3783,7 @@ stack traceback:
         end)
       ]])
       screen:expect({
-        any = pesc('E5560: vim.wait must not be called in a lua loop callback'),
+        any = pesc('E5560: vim.wait must not be called in a fast event context'),
       })
       feed('<CR>')
       assert_alive()

test/functional/vimscript/eval_spec.lua

@@ -25,8 +25,6 @@ local command = n.command
 local write_file = t.write_file
 local api = n.api
 local sleep = vim.uv.sleep
-local matches = t.matches
-local pcall_err = t.pcall_err
 local assert_alive = n.assert_alive
 local poke_eventloop = n.poke_eventloop
 local feed = n.feed
@@ -227,72 +225,6 @@ describe('listing functions using :function', function()
       exec_capture(('function <lambda>%s'):format(num))
     )
   end)
-
-  it('does not crash if another function is deleted while listing', function()
-    local _ = Screen.new(80, 24)
-    matches(
-      'Vim%(function%):E454: Function list was modified$',
-      pcall_err(
-        exec_lua,
-        [=[
-      vim.cmd([[
-        func Func1()
-        endfunc
-        func Func2()
-        endfunc
-        func Func3()
-        endfunc
-      ]])
-
-      local ns = vim.api.nvim_create_namespace('test')
-
-      vim.ui_attach(ns, { ext_messages = true }, function(event, _, content)
-        if event == 'msg_show' and content[1][2] == 'function Func1()'  then
-          vim.cmd('delfunc Func3')
-        end
-      end)
-
-      vim.cmd('function')
-
-      vim.ui_detach(ns)
-    ]=]
-      )
-    )
-    assert_alive()
-  end)
-
-  it('does not crash if the same function is deleted while listing', function()
-    local _ = Screen.new(80, 24)
-    matches(
-      'Vim%(function%):E454: Function list was modified$',
-      pcall_err(
-        exec_lua,
-        [=[
-      vim.cmd([[
-        func Func1()
-        endfunc
-        func Func2()
-        endfunc
-        func Func3()
-        endfunc
-      ]])
-
-      local ns = vim.api.nvim_create_namespace('test')
-
-      vim.ui_attach(ns, { ext_messages = true }, function(event, _, content)
-        if event == 'msg_show' and content[1][2] == 'function Func1()'  then
-          vim.cmd('delfunc Func2')
-        end
-      end)
-
-      vim.cmd('function')
-
-      vim.ui_detach(ns)
-    ]=]
-      )
-    )
-    assert_alive()
-  end)
 end)
 
 it('no double-free in garbage collection #16287', function()