Displaying errors during startup

[Lennart Borgman]

After the recent discussion about error messages at startup (this time 
it was about pure-space-overflow) it came to my mind I often tend to 
miss errors at startup. You can not see them because of the splash 
screen for example. I just started testing `lwarn' because of this. I 
did something like this:

   (condition-case err
       (require 'something-bad)
     (error
      (lwarn '(.emacs) :error "%s" (error-message-string err))))

This displays the error in a nice way even during startup. Looking a bit 
closer at it it seems to be some trouble with using `pop-to-buffer' in 
startup.el when loading .emacs. I therefore suggest using 
`display-buffer' instead like lwarn does. It would also be nice to have 
a more visible face when putting this in the message buffer. I therefore 
suggest using something like the code below in startup.el (around line 905):

 (if init-file-debug
     (load inner)
   (condition-case error
       (load inner)
     (error
      (let ((message-log-max nil))
        (save-excursion
          (set-buffer (get-buffer-create "*Messages*"))
          (let ((s
                 (concat
                  "\n\n"
                  (format "An error has occurred while loading `%s':\n\n"
                          user-init-file)
                  (format "%s%s%s"
                          (get (car error) 'error-message)
                          (if (cdr error) ": " "")
                          (mapconcat (lambda (s) (prin1-to-string s t)) 
(cdr error) ", "))
                  "\n\n"
                  "To ensure normal operation, you should investigate 
and remove the\n"
                  "cause of the error in your initialization file.  
Start Emacs with\n"
                  "the `--debug-init' option to view a complete error 
backtrace.\n\n")))
            (put-text-property
             0 (length s)
             'face 'font-lock-warning-face
             s)
            (insert s)
            (insert "\n") ;; Needed to get normal face again.
            (message "Error in init file: %s%s%s"
                     (get (car error) 'error-message)
                     (if (cdr error) ": " "")
                     (mapconcat 'prin1-to-string (cdr error) ", "))
            ;;(let ((pop-up-windows nil))
            ;;  (pop-to-buffer "*Messages*"))
            (display-buffer "*Messages*") ;; display-buffer does the job.
            (sit-for 10) ;; sit-for is necessary to display the info at 
once.
            (setq init-file-had-error t)))))))

Maybe this would be good to do before the release because it makes it 
somewhat easier to trap errors.