Ensure redisplay after evaluation

* lisp/progmodes/elisp-mode.el (elisp--eval-last-sexp): Revert
last change.
* lisp/frame.el (redisplay--variables): Populate the
redisplay--variables list.
* src/xdisp.c (maybe_set_redisplay): New function.
(syms_of_xdisp) <redisplay--variables>: New variable.
* src/window.h (maybe_set_redisplay): Declare prototype.
* src/data.c (set_internal): Call maybe_set_redisplay.  (Bug#21835)

2 files changed, 10 insertions, 11 deletions

diff --git a/lisp/frame.el b/lisp/frame.el
index f5508517dc6..4b23cb20ac4 100644
--- a/lisp/frame.el
+++ b/lisp/frame.el
@@ -2231,6 +2231,13 @@ See also `toggle-frame-maximized'."
 (make-obsolete-variable
  'window-system-version "it does not give useful information." "24.3")
 
+;; These variables should trigger redisplay of the current buffer.
+(setq redisplay--variables
+      '(line-spacing
+        overline-margin
+        line-prefix
+        wrap-prefix))
+
 (provide 'frame)
 
 ;;; frame.el ends here
diff --git a/lisp/progmodes/elisp-mode.el b/lisp/progmodes/elisp-mode.el
index daf5e41d288..8ea17b74ddb 100644
--- a/lisp/progmodes/elisp-mode.el
+++ b/lisp/progmodes/elisp-mode.el
@@ -1116,17 +1116,9 @@ include additional formats for integers \(octal, hexadecimal, and
 character)."
   (let ((standard-output (if eval-last-sexp-arg-internal (current-buffer) t)))
     ;; Setup the lexical environment if lexical-binding is enabled.
-    (prog1
-        (elisp--eval-last-sexp-print-value
-         (eval (eval-sexp-add-defvars (elisp--preceding-sexp)) lexical-binding)
-         eval-last-sexp-arg-internal)
-      ;; If we are going to display the result in the echo area, force
-      ;; a more thorough redisplay, in case the sexp we evaluated
-      ;; changes something that should affect the display of the
-      ;; current window.  Otherwise, Emacs might decide that only the
-      ;; echo area needs to be redisplayed.
-      (if (eq standard-output t)
-          (force-mode-line-update 'all)))))
+    (elisp--eval-last-sexp-print-value
+     (eval (eval-sexp-add-defvars (elisp--preceding-sexp)) lexical-binding)
+     eval-last-sexp-arg-internal)))
 
 (defun elisp--eval-last-sexp-print-value (value &optional eval-last-sexp-arg-internal)
   (let ((unabbreviated (let ((print-length nil) (print-level nil))