org-mode-drawertextprop.patch

diff --git a/lisp/org-clock.el b/lisp/org-clock.el
index 34179096d..463b28f47 100644
--- a/lisp/org-clock.el
+++ b/lisp/org-clock.el
@@ -1359,14 +1359,14 @@ the default behavior."
 	   (sit-for 2)
 	   (throw 'abort nil))
 	  (t
-	   (insert-before-markers "\n")
+	   (insert-before-markers-and-inherit "\n")
 	   (backward-char 1)
 	   (when (and (save-excursion
 			(end-of-line 0)
 			(org-in-item-p)))
 	     (beginning-of-line 1)
 	     (indent-line-to (- (current-indentation) 2)))
-	   (insert org-clock-string " ")
+	   (insert-and-inherit org-clock-string " ")
 	   (setq org-clock-effort (org-entry-get (point) org-effort-property))
 	   (setq org-clock-total-time (org-clock-sum-current-item
 				       (org-clock-get-sum-start)))
@@ -1658,7 +1658,7 @@ to, overriding the existing value of `org-clock-out-switch-to-state'."
 	    (if fail-quietly (throw 'exit nil) (error "Clock start time is gone")))
 	  (goto-char (match-end 0))
 	  (delete-region (point) (point-at-eol))
-	  (insert "--")
+	  (insert-and-inherit "--")
 	  (setq te (org-insert-time-stamp (or at-time now) 'with-hm 'inactive))
 	  (setq s (org-time-convert-to-integer
 		   (time-subtract
@@ -1666,7 +1666,7 @@ to, overriding the existing value of `org-clock-out-switch-to-state'."
 		    (org-time-string-to-time ts)))
 		h (floor s 3600)
 		m (floor (mod s 3600) 60))
-	  (insert " => " (format "%2d:%02d" h m))
+	  (insert-and-inherit " => " (format "%2d:%02d" h m))
 	  (move-marker org-clock-marker nil)
 	  (move-marker org-clock-hd-marker nil)
 	  ;; Possibly remove zero time clocks.  However, do not add
diff --git a/lisp/org-macs.el b/lisp/org-macs.el
index a02f713ca..4b0e23f6a 100644
--- a/lisp/org-macs.el
+++ b/lisp/org-macs.el
@@ -682,7 +682,7 @@ When NEXT is non-nil, check the next line instead."
 
 
 
-;;; Overlays
+;;; Overlays and text properties
 
 (defun org-overlay-display (ovl text &optional face evap)
   "Make overlay OVL display TEXT with face FACE."
@@ -705,18 +705,44 @@ If DELETE is non-nil, delete all those overlays."
 	    (delete (delete-overlay ov))
 	    (t (push ov found))))))
 
+(defun org--find-text-property-region (pos prop)
+  "Find a region containing PROP text property around point POS."
+  (let* ((beg (and (get-text-property pos prop) pos))
+	 (end beg))
+    (when beg
+      ;; when beg is the first point in the region, `previous-single-property-change'
+      ;; will return nil.
+      (setq beg (or (previous-single-property-change pos prop)
+		    beg))
+      ;; when end is the last point in the region, `next-single-property-change'
+      ;; will return nil.
+      (setq end (or (next-single-property-change pos prop)
+		    end))
+      (unless (= beg end) ; this should not happen
+        (cons beg end)))))
+
 (defun org-flag-region (from to flag spec)
   "Hide or show lines from FROM to TO, according to FLAG.
 SPEC is the invisibility spec, as a symbol."
-  (remove-overlays from to 'invisible spec)
-  ;; Use `front-advance' since text right before to the beginning of
-  ;; the overlay belongs to the visible line than to the contents.
-  (when flag
-    (let ((o (make-overlay from to nil 'front-advance)))
-      (overlay-put o 'evaporate t)
-      (overlay-put o 'invisible spec)
-      (overlay-put o 'isearch-open-invisible #'delete-overlay))))
-
+  (pcase spec
+    ('outline
+     (remove-overlays from to 'invisible spec)
+     ;; Use `front-advance' since text right before to the beginning of
+     ;; the overlay belongs to the visible line than to the contents.
+     (when flag
+       (let ((o (make-overlay from to nil 'front-advance)))
+	 (overlay-put o 'evaporate t)
+	 (overlay-put o 'invisible spec)
+	 (overlay-put o 'isearch-open-invisible #'delete-overlay))))
+    (_
+     ;; Use text properties instead of overlays for speed.
+     ;; Overlays are too slow (Emacs Bug#35453).
+     (with-silent-modifications
+       (remove-text-properties from to '(invisible nil))
+       (when flag
+	 (put-text-property from to 'rear-non-sticky nil)
+	 (put-text-property from to 'front-sticky t)
+	 (put-text-property from to 'invisible spec))))))
 
 
 ;;; Regexp matching
diff --git a/lisp/org.el b/lisp/org.el
index 287fe30e8..335f68a85 100644
--- a/lisp/org.el
+++ b/lisp/org.el
@@ -114,6 +114,7 @@ Stars are put in group 1 and the trimmed body in group 2.")
 (declare-function cdlatex-math-symbol "ext:cdlatex")
 (declare-function Info-goto-node "info" (nodename &optional fork strict-case))
 (declare-function isearch-no-upper-case-p "isearch" (string regexp-flag))
+(declare-function isearch-filter-visible "isearch" (beg end))
 (declare-function org-add-archive-files "org-archive" (files))
 (declare-function org-agenda-entry-get-agenda-timestamp "org-agenda" (pom))
 (declare-function org-agenda-list "org-agenda" (&optional arg start-day span with-hour))
@@ -4869,6 +4870,10 @@ The following commands are available:
   (setq-local outline-isearch-open-invisible-function
 	      (lambda (&rest _) (org-show-context 'isearch)))
 
+  ;; Make isearch search in blocks hidden via text properties
+  (setq-local isearch-filter-predicate #'org--isearch-filter-predicate)
+  (add-hook 'isearch-mode-end-hook #'org--clear-isearch-overlays nil 'local)
+
   ;; Setup the pcomplete hooks
   (setq-local pcomplete-command-completion-function #'org-pcomplete-initial)
   (setq-local pcomplete-command-name-function #'org-command-at-point)
@@ -5859,9 +5864,26 @@ If TAG is a number, get the corresponding match group."
 	 (inhibit-modification-hooks t)
 	 deactivate-mark buffer-file-name buffer-file-truename)
     (decompose-region beg end)
+    ;; do not remove invisible text properties specified by
+    ;; 'org-hide-block and 'org-hide-drawer (but remove  'org-link)
+    ;; this is needed to keep the drawers and blocks hidden unless
+    ;; they are toggled by user
+    ;; Note: The below may be too specific and create troubles
+    ;; if more invisibility specs are added to org in future
+    (let ((pos beg)
+	  next spec)
+      (while (< pos end)
+	(setq next (next-single-property-change pos 'invisible nil end)
+              spec (get-text-property pos 'invisible))
+        (unless (memq spec (list 'org-hide-block
+				 'org-hide-drawer))
+          (remove-text-properties pos next '(invisible t)))
+        (setq pos next)))
     (remove-text-properties beg end
 			    '(mouse-face t keymap t org-linked-text t
-					 invisible t intangible t
+					 ;; Do not remove all invisible during fontification
+					 ;; invisible t
+                                         intangible t
 					 org-emphasis t))
     (org-remove-font-lock-display-properties beg end)))
 
@@ -6677,8 +6699,13 @@ information."
     ;; expose it.
     (dolist (o (overlays-at (point)))
       (when (memq (overlay-get o 'invisible)
-		  '(org-hide-block org-hide-drawer outline))
+		  '(outline))
 	(delete-overlay o)))
+    (when (memq (get-text-property (point) 'invisible)
+		'(org-hide-block org-hide-drawer))
+      (let ((spec (get-text-property (point) 'invisible))
+	    (region (org--find-text-property-region (point) 'invisible)))
+	(org-flag-region (car region) (cdr region) nil spec)))
     (unless (org-before-first-heading-p)
       (org-with-limited-levels
        (cl-case detail
@@ -10849,8 +10876,8 @@ EXTRA is additional text that will be inserted into the notes buffer."
 	 (unless (eq org-log-note-purpose 'clock-out)
 	   (goto-char (org-log-beginning t)))
 	 ;; Make sure point is at the beginning of an empty line.
-	 (cond ((not (bolp)) (let ((inhibit-read-only t)) (insert "\n")))
-	       ((looking-at "[ \t]*\\S-") (save-excursion (insert "\n"))))
+	 (cond ((not (bolp)) (let ((inhibit-read-only t)) (insert-and-inherit "\n")))
+	       ((looking-at "[ \t]*\\S-") (save-excursion (insert-and-inherit "\n"))))
 	 ;; In an existing list, add a new item at the top level.
 	 ;; Otherwise, indent line like a regular one.
 	 (let ((itemp (org-in-item-p)))
@@ -10860,12 +10887,12 @@ EXTRA is additional text that will be inserted into the notes buffer."
 				(goto-char itemp) (org-list-struct))))
 		  (org-list-get-ind (org-list-get-top-point struct) struct)))
 	     (org-indent-line)))
-	 (insert (org-list-bullet-string "-") (pop lines))
+	 (insert-and-inherit (org-list-bullet-string "-") (pop lines))
 	 (let ((ind (org-list-item-body-column (line-beginning-position))))
 	   (dolist (line lines)
-	     (insert "\n")
+	     (insert-and-inherit "\n")
 	     (indent-line-to ind)
-	     (insert line)))
+	     (insert-and-inherit line)))
 	 (message "Note stored")
 	 (org-back-to-heading t))
 	;; Fix `buffer-undo-list' when `org-store-log-note' is called
@@ -13036,10 +13063,10 @@ decreases scheduled or deadline date by one day."
 	      (progn (delete-region (match-beginning 0) (match-end 0))
 		     (goto-char (match-beginning 0)))
 	    (goto-char end)
-	    (insert "\n")
+	    (insert-and-inherit "\n")
 	    (backward-char))
-	  (insert ":" property ":")
-	  (when value (insert " " value))
+	  (insert-and-inherit ":" property ":")
+	  (when value (insert-and-inherit " " value))
 	  (org-indent-line)))))
     (run-hook-with-args 'org-property-changed-functions property value)))
 
@@ -14177,7 +14204,7 @@ The command returns the inserted time stamp."
   (let ((fmt (funcall (if with-hm 'cdr 'car) org-time-stamp-formats))
 	stamp)
     (when inactive (setq fmt (concat "[" (substring fmt 1 -1) "]")))
-    (insert-before-markers (or pre ""))
+    (insert-before-markers-and-inherit (or pre ""))
     (when (listp extra)
       (setq extra (car extra))
       (if (and (stringp extra)
@@ -14188,8 +14215,8 @@ The command returns the inserted time stamp."
 	(setq extra nil)))
     (when extra
       (setq fmt (concat (substring fmt 0 -1) extra (substring fmt -1))))
-    (insert-before-markers (setq stamp (format-time-string fmt time)))
-    (insert-before-markers (or post ""))
+    (insert-before-markers-and-inherit (setq stamp (format-time-string fmt time)))
+    (insert-before-markers-and-inherit (or post ""))
     (setq org-last-inserted-timestamp stamp)))
 
 (defun org-toggle-time-stamp-overlays ()
@@ -20913,6 +20940,79 @@ Started from `gnus-info-find-node'."
           (t default-org-info-node))))))
 
 
+
+;;; Make isearch search in some text hidden via text propertoes
+
+(defvar org--isearch-overlays nil
+  "List of overlays temporarily created during isearch.
+This is used to allow searching in regions hidden via text properties.
+As for [2020-05-09 Sat], Isearch only has special handling of hidden overlays.
+Any text hidden via text properties is not revealed even if `search-invisible'
+is set to 't.")
+
+;; Not sure if it needs to be a user option
+;; One might want to reveal hidden text in, for example, hidden parts of the links.
+;; Currently, hidden text in links is never revealed by isearch.
+(defvar org-isearch-specs '(org-hide-block
+			 org-hide-drawer)
+  "List of text invisibility specs to be searched by isearch.
+By default ([2020-05-09 Sat]), isearch does not search in hidden text,
+which was made invisible using text properties. Isearch will be forced
+to search in hidden text with any of the listed 'invisible property value.")
+
+(defun org--create-isearch-overlays (beg end)
+  "Replace text property invisibility spec by overlays between BEG and END.
+All the regions with invisibility text property spec from
+`org-isearch-specs' will be changed to use overlays instead
+of text properties. The created overlays will be stored in
+`org--isearch-overlays'."
+  (let ((pos beg))
+    (while (< pos end)
+      (when-let* ((spec (get-text-property pos 'invisible))
+		  (spec (memq spec org-isearch-specs))
+		  (region (org--find-text-property-region pos 'invisible)))
+        ;; Changing text properties is considered buffer modification.
+        ;; We do not want it here.
+	(with-silent-modifications
+          ;; The overlay is modelled after `org-flag-region' [2020-05-09 Sat]
+          ;; overlay for 'outline blocks.
+          (let ((o (make-overlay (car region) (cdr region) nil 'front-advance)))
+	    (overlay-put o 'evaporate t)
+	    (overlay-put o 'invisible spec)
+            ;; `delete-overlay' here means that spec information will be lost
+            ;; for the region. The region will remain visible.
+	    (overlay-put o 'isearch-open-invisible #'delete-overlay)
+            (push o org--isearch-overlays))
+	  (remove-text-properties (car region) (cdr region) '(invisible nil))))
+      (setq pos (next-single-property-change pos 'invisible nil end)))))
+
+(defun org--isearch-filter-predicate (beg end)
+  "Return non-nil if text between BEG and END is deemed visible by Isearch.
+This function is intended to be used as `isearch-filter-predicate'.
+Unlike `isearch-filter-visible', make text with 'invisible text property
+value listed in `org-isearch-specs' visible to Isearch."
+  (org--create-isearch-overlays beg end) ;; trick isearch by creating overlays in place of invisible text
+  (isearch-filter-visible beg end))
+
+(defun org--clear-isearch-overlay (ov)
+  "Convert OV region back into using text properties."
+  (when-let ((spec (overlay-get ov 'invisible))) ;; ignore deleted overlays
+    ;; Changing text properties is considered buffer modification.
+    ;; We do not want it here.
+    (with-silent-modifications
+      (put-text-property (overlay-start ov) (overlay-end ov) 'invisible spec)))
+  (when (member ov isearch-opened-overlays)
+    (setq isearch-opened-overlays (delete ov isearch-opened-overlays)))
+  (delete-overlay ov))
+
+(defun org--clear-isearch-overlays ()
+  "Convert overlays from `org--isearch-overlays' back into using text properties."
+  (when org--isearch-overlays
+    (mapc #'org--clear-isearch-overlay org--isearch-overlays)
+    (setq org--isearch-overlays nil)))
+
+
+
 ;;; Finish up
 
 (add-hook 'org-mode-hook     ;remove overlays when changing major mode