New option `org-archive-subtree-save-file-p'

* lisp/org-agenda.el (org-agenda-archive-with): Bind
`org-archive-from-agenda' to `t' when archiving from agenda.

* lisp/org-archive.el (org-archive-subtree-save-file-p): New option.
(org-archive-subtree): Use the new option.

* doc/org-manual.org (Moving a tree to an archive file):
Mention the new option.

Thanks to Russ Allbery for suggesting a similar idea.

doc/org-manual.org

@@ -7209,6 +7209,10 @@ came, its outline path the archiving time etc.  Configure the variable
 ~org-archive-save-context-info~ to adjust the amount of information
 added.
 
+#+vindex: org-archive-subtree-save-file-p
+When ~org-archive-subtree-save-file-p~ is non-~nil~, save the target
+archive buffer.
+
 *** Internal archiving
 :PROPERTIES:
 :DESCRIPTION: Switch off a tree but keep it in the file.

etc/ORG-NEWS

@@ -32,7 +32,7 @@ window header line when this first row is not visible anymore in the
 buffer.
 
 You can activate this minor mode by default by setting the option
-~org-table-electric-header-p~ to ~t~.
+~org-table-electric-header-p~ to =t=.
 
 *** Property drawers allowed before first headline
 
@@ -44,16 +44,28 @@ properties will work also for this level.  In other words: defining
 things in a property drawer before the first headline will make them
 "inheritable" for all headlines.
 
-*** New option to group captured datetime entries by month
-
-A new `:tree-type month' option was added to org-capture-templates to
-group new datetime entries by month.
-
 *** Refinement in window behavior on exiting Org source buffer
 
 After editing a source block, Org will restore the window layout when
 ~org-src-window-setup~ is set to a value that modifies the layout.
 
+*** Babel: new header argument to pass Java command line arguments
+
+Babel Java blocks recognize header argument =:cmdargs= and pass its
+value in call to =java=.
+
+** New options
+
+*** New option ~org-table-electric-header-p~
+
+Setting this option to =t= will activate
+~org-table-electric-header-mode~ in org-mode buffers.
+
+*** New option to group captured datetime entries by month
+
+A new `:tree-type month' option was added to org-capture-templates to
+group new datetime entries by month.
+
 *** New option to show source buffers using "plain" display-buffer
 
 Added option ~plain~ to ~org-src-window-setup~ to show source buffers
@@ -61,15 +73,21 @@ using ~display-buffer~. This allows users to control how source
 buffers are displayed by modifying ~display-buffer-alist~ or
 ~display-buffer-base-action~.
 
+*** New option ~org-archive-subtree-save-file-p~
+
+Archiving a subtree used to always save the target archive buffer.
+Commit [[https://code.orgmode.org/bzg/org-mode/commit/b186d1d7][b186d1d7]] changed this behavior by always not saving the target
+buffer, because batch archiving from agenda could take too much time.
+
+This new option ~org-archive-subtree-save-file-p~ defaults to the
+value =from-org= so that archiving a subtree will save the target
+buffer when done from an org-mode buffer, but not from the agenda.
+You can also set this option to =t= or to =from-agenda=.
+
 *** New option ~org-show-notification-timeout~
 
 This option will add a timeout to notifications.
 
-*** Babel: new header argument to pass Java command line arguments
-
-Babel Java blocks recognize header argument =:cmdargs= and pass its
-value in call to =java=.
-
 ** New commands
 *** ~org-table-electric-header-mode~
 
@@ -1392,9 +1410,9 @@ removed from Gnus circa September 2010.
 
 *** ~org-agenda-repeating-timestamp-show-all~ is removed.
 
-For an equivalent to a ~nil~ value, set
+For an equivalent to a =nil= value, set
 ~org-agenda-show-future-repeats~ to nil and
-~org-agenda-prefer-last-repeat~ to ~t~.
+~org-agenda-prefer-last-repeat~ to =t=.
 
 *** ~org-gnus-nnimap-query-article-no-from-file~ is removed.
 
@@ -1412,7 +1430,7 @@ equivalent to the removed format string.
 
 *** ~org-enable-table-editor~ is removed.
 
-Setting it to a ~nil~ value broke some other features (e.g., speed
+Setting it to a =nil= value broke some other features (e.g., speed
 keys).
 
 *** ~org-export-use-babel~ cannot be set to ~inline-only~

lisp/org-agenda.el

@@ -8810,7 +8810,8 @@ Point is in the buffer where the item originated.")
 		(let ((org-agenda-buffer-name bufname-orig))
 		  (org-remove-subtree-entries-from-agenda))
 		(org-back-to-heading t)
-		(funcall cmd)))
+		(let ((org-archive-from-agenda t))
+		  (funcall cmd))))
 	  (error "Archiving works only in Org files"))))))
 
 (defun org-remove-subtree-entries-from-agenda (&optional buf beg end)

lisp/org-archive.el

@@ -91,6 +91,15 @@ When a string, a %s formatter will be replaced by the file name."
 	  (const :tag "When archiving a subtree to the same file" infile)
 	  (const :tag "Always" t)))
 
+(defcustom org-archive-subtree-save-file-p 'from-org
+  "Non-nil means save the archive file after archiving a subtree."
+  :group 'org-archive
+  :type '(choice
+	  (const :tag "Always save the archive buffer" t)
+	  (const :tag "Save target buffer when archiving from an agenda view" from-agenda)
+	  (const :tag "Save target buffer when archiving from an org buffer" from-org)
+	  (const :tag "Do not save the archive buffer")))
+
 (defcustom org-archive-save-context-info '(time file olpath category todo itags)
   "Parts of context info that should be stored as properties when archiving.
 When a subtree is moved to an archive file, it loses information given by
@@ -361,6 +370,16 @@ direct children of this heading."
 		     (point)
 		     (concat "ARCHIVE_" (upcase (symbol-name item)))
 		     value))))
+	      ;; Save and kill the buffer, if it is not the same
+	      ;; buffer and depending on `org-archive-subtree-save-file-p'
+	      (unless (eq this-buffer buffer)
+		(when (or (eq org-archive-subtree-save-file-p t)
+			  (and (boundp 'org-archive-from-agenda)
+			       (eq org-archive-subtree-save-file-p 'from-agenda)))
+		  (save-buffer)))
+	      ;; (unless (or (not org-archive-subtree-save-file-p)
+	      ;; 		  (eq this-buffer buffer))
+	      ;; 	(save-buffer))
 	      (widen))))
 	;; Here we are back in the original buffer.  Everything seems
 	;; to have worked.  So now run hooks, cut the tree and finish