From 85d11170985a612a8e6c847f56a5c5bf121b97d2 Mon Sep 17 00:00:00 2001
From: stardiviner <numbchild@gmail.com>
Date: Wed, 2 Dec 2020 17:24:29 +0800
Subject: [PATCH] org.el: Complete tags from both global and buffer local

* lisp/org.el (org-fast-tag-selection): Merge buffer local tags with
global alist of tags. And it obey the option
org-complete-tags-always-offer-all-agenda-tags.

* doc/org-manual.org: Update the TAB key doc in tags selection UI.

* etc/ORG-NEWS: Mention the change in org-set-tags-command.
---
 doc/org-manual.org |  6 +++---
 etc/ORG-NEWS       |  5 +++++
 lisp/org.el        | 24 ++++++++++++++----------
 3 files changed, 22 insertions(+), 13 deletions(-)

diff --git a/doc/org-manual.org b/doc/org-manual.org
index b015b502c..01cec4b8d 100644
--- a/doc/org-manual.org
+++ b/doc/org-manual.org
@@ -4860,9 +4860,9 @@ In this interface, you can also use the following special keys:
 
   #+kindex: TAB
   Enter a tag in the minibuffer, even if the tag is not in the
-  predefined list.  You can complete on all tags present in the
-  buffer.  You can also add several tags: just separate them with
-  a comma.
+  predefined list.  You can complete on all tags present in the buffer
+  and globally pre-defined tags from ~org-tag{-persistent}-alist~.
+  You can also add several tags: just separate them with a comma.
 
 - {{{kbd(SPC)}}} ::
 
diff --git a/etc/ORG-NEWS b/etc/ORG-NEWS
index 5e5f1954d..5e68d27c0 100644
--- a/etc/ORG-NEWS
+++ b/etc/ORG-NEWS
@@ -149,6 +149,11 @@ Example:
 A new =u= mode flag for Calc formulas in Org tables has been added to
 enable Calc units simplification mode.
 
+*** =org-set-tags-command= select tags from ~org-global-tags-completion-table~
+
+Let =org-set-tags-command= complete tags from global tags list (both
+buffer-local tags and ~org-tag{-persistent}-alist~).
+
 ** Miscellaneous
 *** =org-goto-first-child= now works before first heading
 
diff --git a/lisp/org.el b/lisp/org.el
index 5b0ae389c..ba816dfa6 100644
--- a/lisp/org.el
+++ b/lisp/org.el
@@ -12139,7 +12139,7 @@ (defun org-fast-tag-selection (current inherited table &optional todo-table)
 				  fulltable))))
 	 (buf (current-buffer))
 	 (expert (eq org-fast-tag-selection-single-key 'expert))
-	 (buffer-tags nil)
+	 (tab-tags nil)
 	 (fwidth (+ maxlen 3 1 3))
 	 (ncol (/ (- (window-width) 4) fwidth))
 	 (i-face 'org-done)
@@ -12274,16 +12274,20 @@ (defun org-fast-tag-selection (current inherited table &optional todo-table)
 		    (setq current nil)
 		    (when exit-after-next (setq exit-after-next 'now)))
 		   ((= c ?\t)
-		    (condition-case nil
-			(setq tg (completing-read
-				  "Tag: "
-				  (or buffer-tags
-				      (with-current-buffer buf
-					(setq buffer-tags
-					      (org-get-buffer-tags))))))
-		      (quit (setq tg "")))
+                    (unless tab-tags
+                      (setq tab-tags
+                            (delq nil
+                                  (mapcar (lambda (x)
+                                            (let ((item (car-safe x)))
+                                              (and (stringp item)
+                                                   (list item))))
+                                          (org--tag-add-to-alist
+                                           (with-current-buffer buf
+                                             (org-get-buffer-tags))
+                                           table)))))
+                    (setq tg (completing-read "Tag: " tab-tags))
 		    (when (string-match "\\S-" tg)
-		      (cl-pushnew (list tg) buffer-tags :test #'equal)
+		      (cl-pushnew (list tg) tab-tags :test #'equal)
 		      (if (member tg current)
 			  (setq current (delete tg current))
 			(push tg current)))
-- 
2.29.2