bug#57883: compilation-get-file-structure mishandles buffers

[Stefan Kangas <stefankangas@gmail.com>]

reopen 57883
thanks

JD Smith <jdtsmith@gmail.com> writes:

> Thanks for the query.  This is still an issue in Emacs 29 with emacs -Q.

Thanks, reopened.

> Reproducer: The reproduction recipe was in the linked emacs-devel
> <https://lists.gnu.org/archive/html/emacs-devel/2022-02/msg00496.html>
> thread.  Here it is again (with Emacs 29 updates in [brackets]):

I've tried editing your recipe down into something that's a little bit
easier for me to work with.

All of this is pasted into an emacs -Q "*scratch*" buffer:

(progn
  (require 'compile)
  (defun my/filename-function () (list (get-buffer (match-string 1))))
  (defvar my/compilation-error-regexp
    `((,(rx line-start
	    "Buffer \"" (group (+ (not "\""))) "\", " ; 1: buffer name
	    "line" (+ space) (group (+ digit))	    ; 2: line
	    (* nonl) ?\n)
       my/filename-function
       2
       nil nil 1)))
  (progn (compilation-setup)
         (setq compilation-error-regexp-alist my/compilation-error-regexp)
         (compilation-parse-errors (point-min) (point-max)))
  (compilation-parse-errors (point-min) (point-max)))

But this doesn't give me any error when evaluating it either Emacs 29.1
or current master.  Did I miss something?  Perhaps there is some step
missing in my edited recipe?