Merge from origin/emacs-27

071483b6f5 Fix reverting customizations
43203d5068 * lisp/loadup.el: Set max-specpdl-size to 1800 when loadin...
fab3674b36 Revert "Raise default max-specpdl-size value"
42f66aa502 ; Fix NEWS.24
bb9402e6e9 Raise default max-specpdl-size value

etc/NEWS.24

@@ -3604,10 +3604,12 @@ advertised at the time.)
 
 ** Debugger changes
 
-*** New macro `condition-case-unless-debug' (this was actually added in
-Emacs 23.1 as condition-case-no-debug, but not advertised)
+*** New macro `condition-case-unless-debug'.
+(This was actually added in Emacs 23.1 as condition-case-no-debug, but
+not advertised)
 
-*** The macro `with-demoted-errors' was added in Emacs 23.1, but not advertised.
+*** The macro `with-demoted-errors'.
+It was also added in Emacs 23.1, but not advertised.
 
 *** Variable `stack-trace-on-error' removed.
 
@@ -3691,6 +3693,8 @@ argument is supplied (see Trash changes, above).
 
 *** New file predicates: `file-equal-p', `file-in-directory-p'.
 
+*** New function `file-size-human-readable'.
+
 ** Tool-bars can display separators.
 Tool-bar separators are handled like menu separators in menu-bar maps,
 i.e. via menu entries of the form `(menu-item "--")'.

lisp/custom.el

@@ -886,7 +886,10 @@ See `custom-known-themes' for a list of known themes."
 	(put theme 'theme-settings
 	     (cons (list prop symbol theme value)
 		   (delq res theme-settings)))
-	(setcar (cdr setting) value)))
+        ;; It's tempting to use setcar here, but that could
+        ;; inadvertently modify other properties in SYMBOL's proplist,
+        ;; if those just happen to share elements with the value of PROP.
+        (put symbol prop (cons (list theme value) (delq setting old)))))
      ;; Add a new setting:
      (t
       (when (custom--should-apply-setting theme)

lisp/loadup.el

@@ -245,7 +245,9 @@
 (load "language/cham")
 
 (load "indent")
-(load "emacs-lisp/cl-generic")
+(let ((max-specpdl-size (max max-specpdl-size 1800)))
+  ;; A particularly demanding file to load; 1600 does not seem to be enough.
+  (load "emacs-lisp/cl-generic"))
 (load "minibuffer") ;Needs cl-generic (and define-minor-mode).
 (load "frame")
 (load "startup")