Re: max-specpdl-size and default font setting via Custom

[Andrew Hyatt]

mikko.huhtala@abo.fi (Mikko Huhtala) wrote in message 
news:<87e9cb21.0110300051.575377ce@posting.google.com>...
> Posted the following on gnu.emacs.help and the kind people who replied
> suspected that it may be a real bug.
> 
> 
> > I installed Emacs 21.1 on a Mandrake Linux 8.0 system (i586). I get
> > the "Variable binding depth exceeds max-specpdl-size" problem when I
> > set the default font to "monotype.com" using the interactive Custom
> > and evaluate the generated .emacs. The same of course happens at
> > startup. I can increase max-specpdl-size to 2000, and this will get
> > rid of the error in other lisp packages, such as vm, but the font
> > setting fails with "Lisp nesting exceeds max-lisp-eval-depth". If I
> > increase both max-specpdl-size and max-lisp-eval-depth to 9000, emacs
> > crashes trying to evaluate the font setting expression.
> > 
> > The lisp in .emacs written by Custom is as follows
> > 
> > (custom-set-faces
> > ;; custom-set-faces was added by Custom -- don't edit or cut/paste
> > it!
> > ;; Your init file should contain only one such instance.
> > '(default ((t (:stipple nil :background "white" :foreground "black"
> > :inverse-video nil :box nil :strike-through nil :overline nil
> > :underline nil :slant normal :weight normal :height 90 :width normal
> > :family "monotype.com")))))
> > 
> > "monotype.com" is a TrueType font. It usually does get set as the
> > default font despite the error.
> > 
> > Is there an infinite loop somewhere in Custom or the font handling
> > code?
> 
> Mikko


I've also had the same problem on Linux.  In fact, it also caused
tooltips to not work.  I debugged into the problem, and it was caused
by an infinite recursion.  You set the default face in face-spec-set,
which eventually sets it in internal-set-lisp-face-attribute, which
then calls face-set-after-frame-default on the current frame.  That
function gets a list of all faces, and sets them all for the current
buffer.  The faces include the default face, which brings us back to
face-spec-set.  I believe this is a problem specifically with the
default font, and the problem probably lies in
internal-set-lisp-face-attribute.  For now, I have a quick fix (an
alteration to the face-set-after-frame-default function) that I put in
my .emacs file.  I just added a check so that it never processes the
default face.  It fixes the problem, but probably not in the ideal
way...

(defun face-set-after-frame-default (frame)
  "Set frame-local faces of FRAME from face specs and resources.
Initialize colors of certain faces from frame parameters."
  (dolist (face (face-list))
    (when (not (equal face 'default))
      (face-spec-set face (face-user-default-spec face) frame)
      (internal-merge-in-global-face face frame)
      (when (and (memq window-system '(x w32 mac))
                 (or (not (boundp 'inhibit-default-face-x-resources))
                     (not (eq face 'default))))
        (make-face-x-resource-internal face frame)))
    
    ;; Initialize attributes from frame parameters.
    (let ((params '((foreground-color default :foreground)
                    (background-color default :background)
                    (border-color border :background)
                    (cursor-color cursor :background)
                    (scroll-bar-foreground scroll-bar :foreground)
                    (scroll-bar-background scroll-bar :background)
                    (mouse-color mouse :background))))
      (dolist (param params)
        (let ((frame-param (frame-parameter frame (nth 0 param)))
              (face (nth 1 param))
              (attr (nth 2 param)))
          (when (and frame-param
                     ;; Don't override face attributes explicitly
                     ;; specified for new frames.
                     (eq (face-attribute face attr t) 'unspecified))
            (set-face-attribute face frame attr frame-param)))))))