Abolish max-specpdl-size (bug#57911)

The max-lisp-eval-depth limit is sufficient to prevent unbounded stack
growth including the specbind stack; simplify matters for the user by
not having them to worry about two different limits.  This change
turns max-specpdl-size into a harmless variable with no effects,
to keep existing code happy.

* lisp/subr.el (max-specpdl-size):
Define as an ordinary (but obsolete) dynamic variable.
* admin/grammars/Makefile.in:
* doc/lispintro/emacs-lisp-intro.texi (Loops & Recursion):
* doc/lispref/control.texi (Cleanups):
* doc/lispref/edebug.texi (Checking Whether to Stop):
* doc/lispref/eval.texi (Eval):
* doc/lispref/variables.texi (Local Variables):
* doc/misc/calc.texi (Recursion Depth):
Update documentation.
* etc/NEWS: Announce.
* src/eval.c
(FletX): Use safe iteration to guard against circular bindings list.
(syms_of_eval): Remove old max-specpdl-size definition.
(init_eval_once, restore_stack_limits, call_debugger)
(signal_or_quit, grow_specpdl_allocation):
* leim/Makefile.in:
* lisp/Makefile.in:
* lisp/calc/calc-stuff.el (calc-more-recursion-depth)
(calc-less-recursion-depth):
* lisp/calc/calc.el (calc-do):
* lisp/cedet/semantic/ede-grammar.el (ede-proj-makefile-insert-rules):
* lisp/cedet/semantic/grammar.el (semantic-grammar-batch-build-one-package):
* lisp/cus-start.el (standard):
* lisp/emacs-lisp/comp.el (comp--native-compile):
* lisp/emacs-lisp/edebug.el (edebug-max-depth):
(edebug-read-and-maybe-wrap-form, edebug-default-enter):
* lisp/emacs-lisp/regexp-opt.el (regexp-opt):
* lisp/eshell/esh-mode.el (eshell-mode):
* lisp/loadup.el (max-specpdl-size):
* lisp/mh-e/mh-e.el (mh-invisible-headers):
* lisp/net/shr.el (shr-insert-document, shr-descend):
* lisp/play/hanoi.el (hanoi-internal):
* lisp/progmodes/cperl-mode.el:
* src/fileio.c (Fdo_auto_save):
Remove references to and modifications of max-specpdl-size.

1 files changed, 27 insertions, 35 deletions

diff --git a/lisp/net/shr.el b/lisp/net/shr.el
index 54ce9b1a41c..d56420eb02e 100644
--- a/lisp/net/shr.el
+++ b/lisp/net/shr.el
@@ -373,7 +373,6 @@ DOM should be a parse tree as generated by
                  shr-width
                (* shr-width (frame-char-width)))
            (shr--window-width)))
-        (max-specpdl-size max-specpdl-size)
         (shr--link-targets nil)
         (hscroll (window-hscroll))
         ;; `bidi-display-reordering' is supposed to be only used for
@@ -625,41 +624,34 @@ size, and full-buffer size."
         (shr-stylesheet shr-stylesheet)
         (shr-depth (1+ shr-depth))
         (start (point)))
-    ;; shr uses many frames per nested node.
-    (if (and (> shr-depth (/ max-specpdl-size 15))
-             (not (and shr-offer-extend-specpdl
-                       (y-or-n-p "Too deeply nested to render properly; increase `max-specpdl-size'?")
-                       (setq max-specpdl-size (* max-specpdl-size 2)))))
-        (setq shr-warning
-              "Not rendering the complete page because of too-deep nesting")
+    (when style
+      (if (string-match-p "color\\|display\\|border-collapse" style)
+          (setq shr-stylesheet (nconc (shr-parse-style style)
+                                      shr-stylesheet))
+        (setq style nil)))
+    ;; If we have a display:none, then just ignore this part of the DOM.
+    (unless (or (equal (cdr (assq 'display shr-stylesheet)) "none")
+                (and shr-discard-aria-hidden
+                     (equal (dom-attr dom 'aria-hidden) "true")))
+      ;; We don't use shr-indirect-call here, since shr-descend is
+      ;; the central bit of shr.el, and should be as fast as
+      ;; possible.  Having one more level of indirection with its
+      ;; negative effect on performance is deemed unjustified in
+      ;; this case.
+      (cond (external
+             (funcall external dom))
+            ((fboundp function)
+             (funcall function dom))
+            (t
+             (shr-generic dom)))
+      (when-let ((id (dom-attr dom 'id)))
+        (push (cons id (set-marker (make-marker) start)) shr--link-targets))
+      ;; If style is set, then this node has set the color.
       (when style
-        (if (string-match-p "color\\|display\\|border-collapse" style)
-            (setq shr-stylesheet (nconc (shr-parse-style style)
-                                        shr-stylesheet))
-          (setq style nil)))
-      ;; If we have a display:none, then just ignore this part of the DOM.
-      (unless (or (equal (cdr (assq 'display shr-stylesheet)) "none")
-                  (and shr-discard-aria-hidden
-                       (equal (dom-attr dom 'aria-hidden) "true")))
-        ;; We don't use shr-indirect-call here, since shr-descend is
-        ;; the central bit of shr.el, and should be as fast as
-        ;; possible.  Having one more level of indirection with its
-        ;; negative effect on performance is deemed unjustified in
-        ;; this case.
-        (cond (external
-               (funcall external dom))
-              ((fboundp function)
-               (funcall function dom))
-              (t
-               (shr-generic dom)))
-        (when-let ((id (dom-attr dom 'id)))
-          (push (cons id (set-marker (make-marker) start)) shr--link-targets))
-        ;; If style is set, then this node has set the color.
-        (when style
-          (shr-colorize-region
-           start (point)
-           (cdr (assq 'color shr-stylesheet))
-           (cdr (assq 'background-color shr-stylesheet))))))))
+        (shr-colorize-region
+         start (point)
+         (cdr (assq 'color shr-stylesheet))
+         (cdr (assq 'background-color shr-stylesheet)))))))
 
 (defun shr-fill-text (text)
   (if (zerop (length text))