New static initialization blocks support has problems with named IIFE and 'use strict'

[nexushoratio]

I finally updated js2-mode and immediately noticed some problems with my existing code. It would pause/hang on every change. I managed to narrow it down to the following example:

(function foo() {
  'use strict';

  class C {

    static {
    }

  }
}());

In particular, it has to be both:

• A named IIFE function
• Include use strict inside the function

Basically, this is a pattern I use for userscript libraries. The IIFE having a name makes debugging easier than an anonymous function.

When I load the file (or make a change, or run js2-mode-reset), I get the following:

Error running timer ‘js2-mode-idle-reparse’: (wrong-type-argument js2-infix-node #s(js2-scope 131 60 7 ((STATIC t)) nil nil nil #s(js2-function-node 111 2 1 nil nil nil nil nil nil nil nil nil 0 nil nil 0 FUNCTION FUNCTION_EXPRESSION #s(js2-name-node 39 11 3 nil nil "foo" nil) nil nil nil 12 13 nil nil nil nil nil) nil))

I do not recall which version I upgraded from, and have not yet tested to see when it was introduced, but the recent Support for static initialization blocks (https://github.com/mooz/js2-mode/issues/594). seems to be a likely candidate.

Fairly trivial .emacs file:

(package-initialize)

(defalias 'javascript-mode 'js2-mode)

(menu-bar-mode -1)
(custom-set-variables
 ;; custom-set-variables was added by Custom.
 ;; If you edit it by hand, you could mess it up, so be careful.
 ;; Your init file should contain only one such instance.
 ;; If there is more than one, they won't work right.
 '(display-fill-column-indicator-character 124)
 '(fill-column 78)
 '(global-auto-revert-mode t)
 '(global-display-fill-column-indicator-mode t)
 '(indent-tabs-mode nil)
 '(js-indent-level 2)
 '(js2-concat-multiline-strings 'eol)
 '(magit-commit-show-diff nil)
 '(package-archives
   '(("gnu" . "https://elpa.gnu.org/packages/")
     ("nongnu" . "https://elpa.nongnu.org/nongnu/")
     ("melpa" . "https://melpa.org/packages/")))
 '(package-selected-packages '(js2-mode))
 '(sh-basic-offset 2)
 '(show-trailing-whitespace t)
 '(standard-indent 2)
 '(whitespace-action '(auto-cleanup))
 '(whitespace-style
   '(face trailing tabs spaces lines newline empty indentation::tab indentation::space indentation space-after-tab::tab space-after-tab::space space-after-tab space-before-tab::space space-before-tab space-mark tab-mark newline-mark)))
(custom-set-faces
 ;; custom-set-faces was added by Custom.
 ;; If you edit it by hand, you could mess it up, so be careful.
 ;; Your init file should contain only one such instance.
 ;; If there is more than one, they won't work right.
 )

I still consider myself an emacs newbie, so not sure how to run with only js2-mode in an isolated enviroment to verify this is not due to some strange combination of things installed. If info is needed, pointers appreciated.

Running mainline Debian bookworm:

$ dpkg -l | grep -e emacs -e elpa
ii  dh-elpa-helper                       2.0.16                                    all          helper package for emacs lisp extensions
ii  elpa-ag                              0.48-1.1                                  all          Emacs frontend to ag
ii  elpa-dash                            2.19.1+git20220608.1.0ac1ecf+dfsg-1       all          modern list manipulation library for Emacs
ii  elpa-git-commit                      3.3.0-2                                   all          Major mode for editing git commit message
ii  elpa-magit                           3.3.0-2                                   all          Emacs interface for Git
ii  elpa-magit-section                   3.3.0-2                                   all          Collapsible sections like in Magit
ii  elpa-s                               1.12.0-5                                  all          string manipulation library for Emacs
ii  elpa-with-editor                     3.0.5-1                                   all          call program using Emacs as $EDITOR
ii  emacs                                1:28.2+1-15                               all          GNU Emacs editor (metapackage)
ii  emacs-bin-common                     1:28.2+1-15                               amd64        GNU Emacs editor's shared, architecture dependent files
ii  emacs-common                         1:28.2+1-15                               all          GNU Emacs editor's shared, architecture independent infrastructure
ii  emacs-common-non-dfsg                1:28.2+1-2                                all          GNU Emacs common non-DFSG items, including the core documentation
ii  emacs-el                             1:28.2+1-15                               all          GNU Emacs LISP (.el) files
ii  emacs-nox                            1:28.2+1-15                               amd64        GNU Emacs editor (without GUI support)
ii  emacsen-common                       3.0.5                                     all          Common facilities for all emacsen

$ ls .emacs.d/elpa/
archives/  gnupg/  js2-mode-20231225.1150/

[dgutov]

Hi! Not sure from which version you upgraded -- the affected code has been there for a number of years now.

I can also reproduce the same error without IIFE, just with use strict and a static block inside a class.

Anyway, I've pushed a change which should hopefully serve as a good enough workaround, see if you still have problems.

[nexushoratio]

Thanks. I'll give it a try as soon as I can and report back.

FTR, I downgraded to 20230408 and I had no problems with long pauses or error messages. I did experience the issue expressed in #594 .

[nexushoratio]

Ahh, noticed it was on melpa already.

Works great. Many thanks!

[dgutov]

I downgraded to 20230408 and I had no problems with long pauses or error messages

Okay, that actually makes sense: there was no support for static at that time. Though I'd expect the behavior to be the same in both of these cases: file fails to parse, shows some errors in the buffer and in Messages.

Works great. Many thanks!

Welcome!