bug#35316: 26.2; Emacs lags in c++-mode buffer when editing with iedit-mode on

[Zhang Haijun]

>> I’m not the developer of iedit.
> 
> Would you please consider forwarding this email to the maintainer of
> iedit.  Thanks!
> 

Done.

> 
> I saw this comment too.  I had a look at the repository on github, and
> this handling of after-change-functions has been there since at least
> 2012.  :-(
> 
> When I comment out the offending bits of code from
> iedit-update-occurrences-2, like this:
> 
> 
> 
> --- iedit-lib.el~     2019-04-19 08:03:29.000000000 +0000
> +++ iedit-lib.el      2019-05-16 15:58:27.158575662 +0000
> @@ -490,7 +490,7 @@
> 
> (defun iedit-update-occurrences-2 (occurrence after beg end &optional change)
>   ""
> -  (let ((inhibit-modification-hooks t)
> +  (let (;; (inhibit-modification-hooks t)
>         (offset (- beg (overlay-start occurrence)))
>         (value (buffer-substring-no-properties beg end)))
>     (save-excursion
> @@ -509,10 +509,11 @@
>                 ;; non-nil, after-change-functions hooks are not going
>                 ;; to be called for the changes of other occurrences.
>                 ;; So run the hook here.
> -                (run-hook-with-args 'after-change-functions
> -                                    beginning
> -                                    ending
> -                                    change))
> +                ;; (run-hook-with-args 'after-change-functions
> +                ;;                     beginning
> +                ;;                     ending
> +                ;;                     change)
> +             )
>               (iedit-move-conjoined-overlays another-occurrence)))
>         ;; deletion
>         (dolist (another-occurrence (remove occurrence 
> iedit-occurrences-overlays))
> @@ -521,10 +522,11 @@
>             (unless (eq beg end) ;; replacement
>               (goto-char beginning)
>               (insert-and-inherit value))
> -            (run-hook-with-args 'after-change-functions
> -                                beginning
> -                                (+ beginning (- beg end))
> -                                change)))))))
> +            ;; (run-hook-with-args 'after-change-functions
> +            ;;                     beginning
> +            ;;                     (+ beginning (- beg end))
> +            ;;                     change)
> +         ))))))
> 
> (defun iedit-next-occurrence ()
>   "Move forward to the next occurrence in the `iedit'.
> 
> 
> 
> , then iedit-mode and C++ Mode work well together.  In a C++ Mode test
> buffer, just over 16k long, on a variable with 75 copies in it, I press
> C-;.  On editing the copies of these variables, the response is now
> instantaneous.
> 

I tried your patch. And it works as you saied. No lags.