lisp/frameset.el: Let-bind frameset--target-display.

* frameset.el (frameset--target-display): Remove definition; declare.
(frameset-save, frameset-restore): Let-bind frameset--target-display.

1 files changed, 20 insertions, 23 deletions

diff --git a/lisp/frameset.el b/lisp/frameset.el
index 5cd921d5f17..ca0926ab652 100644
--- a/lisp/frameset.el
+++ b/lisp/frameset.el
@@ -417,11 +417,11 @@ Properties can be set with
 ;; `frameset-filter-params' can be useful, even if you're not using
 ;; framesets.  The interface of `frameset-filter-params' is generic
 ;; and does not depend of global state, with one exception: it uses
-;; the internal variable `frameset--target-display' to decide if, and
-;; how, to modify the `display' parameter of FILTERED.  But that
-;; should not represent any problem, because it's only meaningful
-;; when restoring, and customized uses of `frameset-filter-params'
-;; are likely to use their own filter alist and just call
+;; the dynamically bound variable `frameset--target-display' to decide
+;; if, and how, to modify the `display' parameter of FILTERED.  That
+;; should not represent a problem, because it's only meaningful when
+;; restoring, and customized uses of `frameset-filter-params' are
+;; likely to use their own filter alist and just call
 ;;
 ;;   (setq my-filtered (frameset-filter-params my-params my-filters t))
 ;;
@@ -522,13 +522,13 @@ It must return:
 Frame parameters not on this alist are passed intact, as if they were
 defined with ACTION = nil.")
 
-(defvar frameset--target-display nil
-  ;; Either (minibuffer . VALUE) or nil.
-  ;; This refers to the current frame config being processed inside
-  ;; `frameset-restore' and its auxiliary functions (like filtering).
-  ;; If nil, there is no need to change the display.
-  ;; If non-nil, display parameter to use when creating the frame.
-  "Internal use only.")
+;; Dynamically bound in `frameset-save', `frameset-restore'.
+(defvar frameset--target-display)
+;; Either (display . VALUE) or nil.
+;; This refers to the current frame config being processed with
+;; `frameset-filter-params' and its auxiliary filtering functions.
+;; If nil, there is no need to change the display.
+;; If non-nil, display parameter to use when creating the frame.
 
 (defun frameset-switch-to-gui-p (parameters)
   "True when switching to a graphic display.
@@ -760,6 +760,7 @@ PREDICATE is a predicate function, which must return non-nil for frames that
 should be saved; if PREDICATE is nil, all frames from FRAME-LIST are saved.
 PROPERTIES is a user-defined property list to add to the frameset."
   (let* ((list (or (copy-sequence frame-list) (frame-list)))
+         (frameset--target-display nil)
          (frames (cl-delete-if-not #'frame-live-p
                                    (if predicate
                                        (cl-delete-if-not predicate list)
@@ -1141,16 +1142,15 @@ All keyword parameters default to nil."
                      (force-display (if (functionp force-display)
                                         (funcall force-display frame-cfg window-cfg)
                                       force-display))
+                     (frameset--target-display nil)
                      frame to-tty duplicate)
                 ;; Only set target if forcing displays and the target display is different.
-                (cond ((frameset-keep-original-display-p force-display)
-                       (setq frameset--target-display nil))
-                      ((eq (frame-parameter nil 'display) (cdr (assq 'display frame-cfg)))
-                       (setq frameset--target-display nil))
-                      (t
-                       (setq frameset--target-display (cons 'display
-                                                            (frame-parameter nil 'display))
-                             to-tty (null (cdr frameset--target-display)))))
+                (unless (or (frameset-keep-original-display-p force-display)
+                            (eq (frame-parameter nil 'display)
+                                (cdr (assq 'display frame-cfg))))
+                  (setq frameset--target-display (cons 'display
+                                                       (frame-parameter nil 'display))
+                        to-tty (null (cdr frameset--target-display))))
                 ;; Time to restore frames and set up their minibuffers as they were.
                 ;; We only skip a frame (thus deleting it) if either:
                 ;; - we're switching displays, and the user chose the option to delete, or
@@ -1210,9 +1210,6 @@ All keyword parameters default to nil."
     ;; other frames are already visible (discussed in thread for bug#14841).
     (sit-for 0 t)
 
-    ;; Clean temporary caches
-    (setq frameset--target-display nil)
-
     ;; Clean up the frame list
     (when cleanup-frames
       (let ((map nil)