org-agenda-get-todos: Fix for todo keywords that can be interpreted as regexp

* lisp/org-agenda.el (org-agenda-get-todos): Use `regexp-quote' to
match keywords.
(org-select-this-todo-keyword): Add docstring, clarifying the allowed
values.
* testing/lisp/test-org-agenda.el (test-org-agenda/todo-selector): Add
new test.

Reported-by: spookygostee@gmail.com
Link: https://orgmode.org/list/87jztuzzpl.fsf@gmail.com

lisp/org-agenda.el

@@ -4940,7 +4940,10 @@ Press `\\[org-agenda-manipulate-query-add]', \
       "|"))
    "\n"))
 
-(defvar org-select-this-todo-keyword nil)
+(defvar org-select-this-todo-keyword nil
+  "Keyword selector for todo agenda.
+Should either be a keyword, \"*\", or \"|\"-separated list of todo
+keywords.")
 (defvar org-last-arg nil)
 
 (defvar crm-separator)
@@ -5637,11 +5640,11 @@ timestamp and the timestamp type relevant for the sorting strategy in
 			   org-todo-regexp)
 			  (org-select-this-todo-keyword
 			   (concat "\\("
-				   (mapconcat #'identity
-					      (org-split-string
-					       org-select-this-todo-keyword
-					       "|")
-					      "\\|")
+				   (mapconcat #'regexp-quote
+				              (org-split-string
+				               org-select-this-todo-keyword
+				               "|")
+				              "\\|")
 				   "\\)"))
 			  (t org-not-done-regexp))))
 	 marker priority urgency category level tags todo-state

testing/lisp/test-org-agenda.el

@@ -80,6 +80,104 @@
     (should (= 3 (count-lines (point-min) (point-max)))))
   (org-test-agenda--kill-all-agendas))
 
+(ert-deftest test-org-agenda/todo-selector ()
+  "Test selecting keywords in `org-todo-list'."
+  (cl-assert (not org-agenda-sticky) nil "precondition violation")
+  (cl-assert (not (org-test-agenda--agenda-buffers))
+	     nil "precondition violation")
+  (let ((org-todo-keywords
+         '((sequence "[ ]" "[X]")
+           (sequence "TODO" "NEXT" "|" "DONE"))))
+    (org-test-agenda-with-agenda
+     "
+* [ ] Unchecked and will appear in agenda
+* NEXT NEXT will appear in agenda
+* [X] Checked and will not appear in agenda
+* TODO Todo and will appear in agenda
+* DONE Done and will not appear in agenda
+"
+     ;; All todo keywords.
+     (org-todo-list)
+     (set-buffer org-agenda-buffer-name)
+     (should
+      (progn
+        "all todo"
+        (message "%S\n----\n%s\n----\n" org-todo-keywords (buffer-string))
+        (goto-char (point-min))
+        (search-forward "[ ] Unchecked and will appear in agenda" nil t)))
+     (should
+      (progn
+        "all todo"
+        (goto-char (point-min))
+        (search-forward "NEXT NEXT will appear in agenda" nil t)))
+     (should
+      (progn
+        "all todo"
+        (goto-char (point-min))
+        (search-forward "TODO Todo and will appear in agenda" nil t)))
+     
+     ;; All todo keywords, including not done.
+     (org-todo-list "*")
+     (should
+      (progn
+        "all keywords"
+        (goto-char (point-min))
+        (search-forward "[ ] Unchecked and will appear in agenda" nil t)))
+     (should
+      (progn
+        "all keywords"
+        (goto-char (point-min))
+        (search-forward "[X] Checked and will not appear in agenda" nil t)))
+     (should
+      (progn
+        "all keywords"
+        (goto-char (point-min))
+        (search-forward "DONE Done and will not appear in agenda" nil t)))
+     (should
+      (progn
+        "all keywords"
+        (goto-char (point-min))
+        (search-forward "NEXT NEXT will appear in agenda" nil t)))
+     (should
+      (progn
+        "all keywords"
+        (goto-char (point-min))
+        (search-forward "TODO Todo and will appear in agenda" nil t)))
+     ;; Just [ ] regexp-like entry.
+     (org-todo-list "[ ]")
+     (should
+      (progn
+        "[ ] keyword"
+        (goto-char (point-min))
+        (search-forward "[ ] Unchecked and will appear in agenda" nil t)))
+     (should-not
+      (progn
+        "[ ] keyword"
+        (goto-char (point-min))
+        (search-forward "NEXT NEXT will appear in agenda" nil t)))
+     (should-not
+      (progn
+        "[ ] keyword"
+        (goto-char (point-min))
+        (search-forward "TODO Todo and will appear in agenda" nil t)))
+     ;; Two keywords.
+     (org-todo-list "NEXT|TODO")
+     (should-not
+      (progn
+        "NEXT|TODO"
+        (goto-char (point-min))
+        (search-forward "[ ] Unchecked and will appear in agenda" nil t)))
+     (should
+      (progn
+        "NEXT|TODO"
+        (goto-char (point-min))
+        (search-forward "NEXT NEXT will appear in agenda" nil t)))
+     (should
+      (progn
+        "NEXT|TODO"
+        (goto-char (point-min))
+        (search-forward "TODO Todo and will appear in agenda" nil t))))))
+
 (ert-deftest test-org-agenda/scheduled-non-todo ()
   "One informative line in the agenda from scheduled non-todo-keyword-item."
   (cl-assert (not org-agenda-sticky) nil "precondition violation")