1 files changed, 25 insertions, 40 deletions

diff --git a/src/eval.c b/src/eval.c
index ef169e80e27..e722b53fb72 100644
--- a/src/eval.c
+++ b/src/eval.c
@@ -133,8 +133,9 @@ static Lisp_Object Ffetch_bytecode (Lisp_Object);
 void
 init_eval_once (void)
 {
-  specpdl_size = 50;
-  specpdl = (struct specbinding *) xmalloc (specpdl_size * sizeof (struct specbinding));
+  enum { size = 50 };
+  specpdl = (struct specbinding *) xmalloc (size * sizeof (struct specbinding));
+  specpdl_size = size;
   specpdl_ptr = specpdl;
   /* Don't forget to update docs (lispref node "Local Variables").  */
   max_specpdl_size = 1300; /* 1000 is not enough for CEDET's c-by.el.  */
@@ -192,7 +193,7 @@ call_debugger (Lisp_Object arg)
   if (lisp_eval_depth + 40 > max_lisp_eval_depth)
     max_lisp_eval_depth = lisp_eval_depth + 40;
 
-  if (SPECPDL_INDEX () + 100 > max_specpdl_size)
+  if (max_specpdl_size - 100 < SPECPDL_INDEX ())
     max_specpdl_size = SPECPDL_INDEX () + 100;
 
 #ifdef HAVE_WINDOW_SYSTEM
@@ -1357,8 +1358,12 @@ A handler is applicable to an error
 if CONDITION-NAME is one of the error's condition names.
 If an error happens, the first applicable handler is run.
 
-The car of a handler may be a list of condition names
-instead of a single condition name.  Then it handles all of them.
+The car of a handler may be a list of condition names instead of a
+single condition name; then it handles all of them.  If the special
+condition name `debug' is present in this list, it allows another
+condition in the list to run the debugger if `debug-on-error' and the
+other usual mechanisms says it should (otherwise, `condition-case'
+suppresses the debugger).
 
 When a handler handles an error, control returns to the `condition-case'
 and it executes the handler's BODY...
@@ -1461,13 +1466,6 @@ internal_condition_case (Lisp_Object (*bfun) (void), Lisp_Object handlers,
   struct catchtag c;
   struct handler h;
 
-  /* Since Fsignal will close off all calls to x_catch_errors,
-     we will get the wrong results if some are not closed now.  */
-#if HAVE_X_WINDOWS
-  if (x_catching_errors ())
-    abort ();
-#endif
-
   c.tag = Qnil;
   c.val = Qnil;
   c.backlist = backtrace_list;
@@ -1506,13 +1504,6 @@ internal_condition_case_1 (Lisp_Object (*bfun) (Lisp_Object), Lisp_Object arg,
   struct catchtag c;
   struct handler h;
 
-  /* Since Fsignal will close off all calls to x_catch_errors,
-     we will get the wrong results if some are not closed now.  */
-#if HAVE_X_WINDOWS
-  if (x_catching_errors ())
-    abort ();
-#endif
-
   c.tag = Qnil;
   c.val = Qnil;
   c.backlist = backtrace_list;
@@ -1555,13 +1546,6 @@ internal_condition_case_2 (Lisp_Object (*bfun) (Lisp_Object, Lisp_Object),
   struct catchtag c;
   struct handler h;
 
-  /* Since Fsignal will close off all calls to x_catch_errors,
-     we will get the wrong results if some are not closed now.  */
-#if HAVE_X_WINDOWS
-  if (x_catching_errors ())
-    abort ();
-#endif
-
   c.tag = Qnil;
   c.val = Qnil;
   c.backlist = backtrace_list;
@@ -1604,13 +1588,6 @@ internal_condition_case_n (Lisp_Object (*bfun) (ptrdiff_t, Lisp_Object *),
   struct catchtag c;
   struct handler h;
 
-  /* Since Fsignal will close off all calls to x_catch_errors,
-     we will get the wrong results if some are not closed now.  */
-#if HAVE_X_WINDOWS
-  if (x_catching_errors ())
-    abort ();
-#endif
-
   c.tag = Qnil;
   c.val = Qnil;
   c.backlist = backtrace_list;
@@ -1727,6 +1704,10 @@ See also the function `condition-case'.  */)
       && (!NILP (Vdebug_on_signal)
           /* If no handler is present now, try to run the debugger.  */
           || NILP (clause)
+          /* A `debug' symbol in the handler list disables the normal
+             suppression of the debugger.  */
+          || (CONSP (clause) && CONSP (XCAR (clause))
+              && !NILP (Fmemq (Qdebug, XCAR (clause))))
           /* Special handler that means "print a message and run debugger
              if requested".  */
           || EQ (h->handler, Qerror)))
@@ -3274,17 +3255,21 @@ static void
 grow_specpdl (void)
 {
   register int count = SPECPDL_INDEX ();
-  if (specpdl_size >= max_specpdl_size)
+  int max_size =
+    min (max_specpdl_size,
+         min (max (PTRDIFF_MAX, SIZE_MAX) / sizeof (struct specbinding),
+              INT_MAX));
+  int size;
+  if (max_size <= specpdl_size)
     {
       if (max_specpdl_size < 400)
-        max_specpdl_size = 400;
-      if (specpdl_size >= max_specpdl_size)
+        max_size = max_specpdl_size = 400;
+      if (max_size <= specpdl_size)
         signal_error ("Variable binding depth exceeds max-specpdl-size", Qnil);
     }
-  specpdl_size *= 2;
-  if (specpdl_size > max_specpdl_size)
-    specpdl_size = max_specpdl_size;
-  specpdl = (struct specbinding *) xrealloc (specpdl, specpdl_size * sizeof (struct specbinding));
+  size = specpdl_size < max_size / 2 ? 2 * specpdl_size : max_size;
+  specpdl = xnrealloc (specpdl, size, sizeof *specpdl);
+  specpdl_size = size;
   specpdl_ptr = specpdl + count;
 }