From d582ed9dc9be516f17dc9a526c3f9615001a46a6 Mon Sep 17 00:00:00 2001
From: Po Lu <luangruo@yahoo.com>
Date: Sat, 5 Apr 2025 10:30:30 +0800
Subject: [PATCH] Disable desktop-restore-frames by default on Android

* lisp/desktop.el (desktop-restore-frames): Default to nil when
\(featurep 'android).

* doc/emacs/misc.texi (Saving Emacs Sessions): Adjust to match.
---
 doc/emacs/misc.texi | 13 ++++++++-----
 etc/NEWS            |  7 +++++++
 lisp/desktop.el     | 10 +++++++---
 3 files changed, 22 insertions(+), 8 deletions(-)

diff --git a/doc/emacs/misc.texi b/doc/emacs/misc.texi
index 08a7f910c5c..8b0f96a3de3 100644
--- a/doc/emacs/misc.texi
+++ b/doc/emacs/misc.texi
@@ -2924,11 +2924,14 @@ can use @kbd{M-x desktop-read} to restore a previously-saved desktop
 if the current Emacs session didn't load any desktop yet.
 
 @vindex desktop-restore-frames
-  By default, the desktop tries to save and restore the frame and
-window configuration.  To disable this, set
-@code{desktop-restore-frames} to @code{nil}.  (See that variable's
-documentation for some related options that you can customize to
-fine-tune this behavior.)
+  By default, the desktop tries to save and restore the frame and window
+configuration.@footnote{Except on Android, where this option defaults to
+@code{nil} because the window manager (@pxref{Android Windowing}) is too
+prohibitive to admit of restoring frame configurations.}  To disable or
+enable this, set @code{desktop-restore-frames} to @code{nil} or any
+non-@code{nil} value respectively.  (See that variable's documentation
+for some related options that you can customize to fine-tune this
+behavior.)
 
 @vindex frameset-filter-alist
   When the desktop restores the frame and window configuration, it
diff --git a/etc/NEWS b/etc/NEWS
index dc77aff7ef2..fc202a795e4 100644
--- a/etc/NEWS
+++ b/etc/NEWS
@@ -2085,6 +2085,13 @@ Put differently, this enables input events to be read and recursive
 editing sessions to be started from non-main threads.  The only platform
 where this remains unsupported is Nextstep (GNUstep or Mac OS).
 
+---
+** 'desktop-restore-frames' has been disabled by default on Android systems.
+Restrictions imposed on clients by the window manager on these systems
+are too prohibitive to admit of restoring frame configurations, and on
+the same account many window management facilities are unimplemented by
+Emacs also.
+
 ---
 ** 'NSSpeechRecognitionUsageDescription' now included in "Info.plist" (macOS).
 Should Emacs (or any built-in shell) invoke a process using macOS speech
diff --git a/lisp/desktop.el b/lisp/desktop.el
index 761d4558700..4067b5a1286 100644
--- a/lisp/desktop.el
+++ b/lisp/desktop.el
@@ -423,13 +423,17 @@ host is off-line."
   :type '(repeat symbol)
   :group 'desktop)
 
-(defcustom desktop-restore-frames t
+(defcustom desktop-restore-frames (not (featurep 'android))
   "When non-nil, save and restore the frame and window configuration.
 See related options `desktop-restore-reuses-frames',
-`desktop-restore-in-current-display', and `desktop-restore-forces-onscreen'."
+`desktop-restore-in-current-display', and `desktop-restore-forces-onscreen'.
+
+This option is enabled by default elsewhere than on Android, where it is
+disabled by default as programs are too handicapped by the window
+manager for frames to be restored."
   :type 'boolean
   :group 'desktop
-  :version "24.4")
+  :version "31.1")
 
 (defcustom desktop-restore-in-current-display t
   "Controls how restoring of frames treats displays.