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.

3 files changed, 2 insertions, 6 deletions

diff --git a/lisp/emacs-lisp/comp.el b/lisp/emacs-lisp/comp.el
index a9087313b18..35acbff9b17 100644
--- a/lisp/emacs-lisp/comp.el
+++ b/lisp/emacs-lisp/comp.el
@@ -4044,7 +4044,6 @@ the deferred compilation mechanism."
             (list "Not a function symbol or file" function-or-file)))
   (catch 'no-native-compile
     (let* ((print-symbols-bare t)
-           (max-specpdl-size (max max-specpdl-size 5000))
            (data function-or-file)
            (comp-native-compiling t)
            (byte-native-qualities nil)
diff --git a/lisp/emacs-lisp/edebug.el b/lisp/emacs-lisp/edebug.el
index 31c05057bfa..67704bdb51c 100644
--- a/lisp/emacs-lisp/edebug.el
+++ b/lisp/emacs-lisp/edebug.el
@@ -129,7 +129,7 @@ contains an infinite loop.  When Edebug is instrumenting code
 containing very large quoted lists, it may reach this limit and give
 the error message \"Too deep - perhaps infinite loop in spec?\".
 Make this limit larger to countermand that, but you may also need to
-increase `max-lisp-eval-depth' and `max-specpdl-size'."
+increase `max-lisp-eval-depth'."
   :type 'integer
   :version "26.1")
 
@@ -1107,8 +1107,7 @@ purpose by adding an entry to this alist, and setting
 	edebug-best-error
 	edebug-error-point
 	;; Do this once here instead of several times.
-	(max-lisp-eval-depth (+ 800 max-lisp-eval-depth))
-	(max-specpdl-size (+ 2000 max-specpdl-size)))
+	(max-lisp-eval-depth (+ 800 max-lisp-eval-depth)))
     (let ((no-match
            (catch 'no-match
              (setq result (edebug-read-and-maybe-wrap-form1))
@@ -2317,7 +2316,6 @@ and run its entry function, and set up `edebug-before' and
               ;; but not inside an unwind-protect.
               ;; Doing it here also keeps it from growing too large.
               (max-lisp-eval-depth (+ 100 max-lisp-eval-depth)) ; too much??
-              (max-specpdl-size (+ 200 max-specpdl-size))
 
               (debugger edebug-debugger) ; only while edebug is active.
               (edebug-outside-debug-on-error debug-on-error)
diff --git a/lisp/emacs-lisp/regexp-opt.el b/lisp/emacs-lisp/regexp-opt.el
index cae5dd00d1d..4d5a39458d2 100644
--- a/lisp/emacs-lisp/regexp-opt.el
+++ b/lisp/emacs-lisp/regexp-opt.el
@@ -133,7 +133,6 @@ usually more efficient than that of a simplified version:
   (save-match-data
     ;; Recurse on the sorted list.
     (let* ((max-lisp-eval-depth 10000)
-	   (max-specpdl-size 10000)
 	   (completion-ignore-case nil)
 	   (completion-regexp-list nil)
 	   (open (cond ((stringp paren) paren) (paren "\\(")))