ox.el: Add :safe declarations to defcustoms

* lisp/ox.el: Add :safe declarations to defcustoms.

lisp/ox.el

@@ -346,21 +346,24 @@ e.g. \"arch:nil\"."
   :type '(choice
 	  (const :tag "Not at all" nil)
 	  (const :tag "Headline only" headline)
-	  (const :tag "Entirely" t)))
+	  (const :tag "Entirely" t))
+  :safe (lambda (x) (memq x 't nil headline)))
 
 (defcustom org-export-with-author t
   "Non-nil means insert author name into the exported file.
 This option can also be set with the OPTIONS keyword,
 e.g. \"author:nil\"."
   :group 'org-export-general
-  :type 'boolean)
+  :type 'boolean
+  :safe #'booleanp)
 
 (defcustom org-export-with-clocks nil
   "Non-nil means export CLOCK keywords.
 This option can also be set with the OPTIONS keyword,
 e.g. \"c:t\"."
   :group 'org-export-general
-  :type 'boolean)
+  :type 'boolean
+  :safe #'booleanp)
 
 (defcustom org-export-with-creator nil
   "Non-nil means the postamble should contain a creator sentence.
@@ -373,14 +376,16 @@ This option can also be set with the OPTIONS keyword, e.g.,
   :group 'org-export-general
   :version "25.1"
   :package-version '(Org . "8.3")
-  :type 'boolean)
+  :type 'boolean
+  :safe #'booleanp)
 
 (defcustom org-export-with-date t
   "Non-nil means insert date in the exported document.
 This option can also be set with the OPTIONS keyword,
 e.g. \"date:nil\"."
   :group 'org-export-general
-  :type 'boolean)
+  :type 'boolean
+  :safe #'booleanp)
 
 (defcustom org-export-date-timestamp-format nil
   "Time-stamp format string to use for DATE keyword.
@@ -393,7 +398,8 @@ string."
   :group 'org-export-general
   :type '(choice
 	  (string :tag "Time-stamp format string")
-	  (const :tag "No format string" nil)))
+	  (const :tag "No format string" nil))
+  :safe (lambda (x) (or (null x) (stringp x))))
 
 (defcustom org-export-creator-string
   (format "Emacs %s (Org mode %s)"
@@ -402,7 +408,8 @@ string."
   "Information about the creator of the document.
 This option can also be set on with the CREATOR keyword."
   :group 'org-export-general
-  :type '(string :tag "Creator string"))
+  :type '(string :tag "Creator string")
+  :safe #'stringp)
 
 (defcustom org-export-with-drawers '(not "LOGBOOK")
   "Non-nil means export contents of standard drawers.
@@ -428,14 +435,20 @@ e.g. \"d:nil\"."
 		(const :format "" not)
 		(repeat :tag "Specify names of drawers to ignore during export"
 			:inline t
-			(string :tag "Drawer name")))))
+			(string :tag "Drawer name"))))
+  :safe (lambda (x) (or (booleanp x)
+			(and (listp x)
+			     (or (cl-every #'stringp x)
+				 (and (eq (nth 0 x) 'not)
+				      (cl-every #'stringp (cdr x))))))))
 
 (defcustom org-export-with-email nil
   "Non-nil means insert author email into the exported file.
 This option can also be set with the OPTIONS keyword,
 e.g. \"email:t\"."
   :group 'org-export-general
-  :type 'boolean)
+  :type 'boolean
+  :safe #'booleanp)
 
 (defcustom org-export-with-emphasize t
   "Non-nil means interpret *word*, /word/, _word_ and +word+.
@@ -447,7 +460,8 @@ respectively.
 This option can also be set with the OPTIONS keyword,
 e.g. \"*:nil\"."
   :group 'org-export-general
-  :type 'boolean)
+  :type 'boolean
+  :safe #'booleanp)
 
 (defcustom org-export-exclude-tags '("noexport")
   "Tags that exclude a tree from export.
@@ -458,7 +472,8 @@ carry one of the `org-export-select-tags' will be removed.
 
 This option can also be set with the EXCLUDE_TAGS keyword."
   :group 'org-export-general
-  :type '(repeat (string :tag "Tag")))
+  :type '(repeat (string :tag "Tag"))
+  :safe (lambda (x) (and (listp x) (cl-every #'stringp x))))
 
 (defcustom org-export-with-fixed-width t
   "Non-nil means export lines starting with \":\".
@@ -467,14 +482,16 @@ e.g. \"::nil\"."
   :group 'org-export-general
   :version "24.4"
   :package-version '(Org . "8.0")
-  :type 'boolean)
+  :type 'boolean
+  :safe #'booleanp)
 
 (defcustom org-export-with-footnotes t
   "Non-nil means Org footnotes should be exported.
 This option can also be set with the OPTIONS keyword,
 e.g. \"f:nil\"."
   :group 'org-export-general
-  :type 'boolean)
+  :type 'boolean
+  :safe #'booleanp)
 
 (defcustom org-export-with-latex t
   "Non-nil means process LaTeX environments and fragments.
@@ -491,7 +508,8 @@ t           Allow export of math snippets."
   :type '(choice
 	  (const :tag "Do not process math in any way" nil)
 	  (const :tag "Interpret math snippets" t)
-	  (const :tag "Leave math verbatim" verbatim)))
+	  (const :tag "Leave math verbatim" verbatim))
+  :safe (lambda (x) (memq x '(t nil verbatim))))
 
 (defcustom org-export-headline-levels 3
   "The last level which is still exported as a headline.
@@ -502,7 +520,8 @@ when exported, but back-end behavior may differ.
 This option can also be set with the OPTIONS keyword,
 e.g. \"H:2\"."
   :group 'org-export-general
-  :type 'integer)
+  :type 'integer
+  :safe #'integerp)
 
 (defcustom org-export-default-language "en"
   "The default language for export and clocktable translations, as a string.
@@ -511,14 +530,16 @@ This may have an association in
 `org-export-smart-quotes-alist' and `org-export-dictionary'.
 This option can also be set with the LANGUAGE keyword."
   :group 'org-export-general
-  :type '(string :tag "Language"))
+  :type '(string :tag "Language")
+  :safe #'stringp)
 
 (defcustom org-export-preserve-breaks nil
   "Non-nil means preserve all line breaks when exporting.
 This option can also be set with the OPTIONS keyword,
 e.g. \"\\n:t\"."
   :group 'org-export-general
-  :type 'boolean)
+  :type 'boolean
+  :safe #'booleanp)
 
 (defcustom org-export-with-entities t
   "Non-nil means interpret entities when exporting.
@@ -532,7 +553,8 @@ and the user option `org-entities-user'.
 This option can also be set with the OPTIONS keyword,
 e.g. \"e:nil\"."
   :group 'org-export-general
-  :type 'boolean)
+  :type 'boolean
+  :safe #'booleanp)
 
 (defcustom org-export-with-inlinetasks t
   "Non-nil means inlinetasks should be exported.
@@ -541,7 +563,8 @@ e.g. \"inline:nil\"."
   :group 'org-export-general
   :version "24.4"
   :package-version '(Org . "8.0")
-  :type 'boolean)
+  :type 'boolean
+  :safe #'booleanp)
 
 (defcustom org-export-with-planning nil
   "Non-nil means include planning info in export.
@@ -554,14 +577,16 @@ e.g. \"p:t\"."
   :group 'org-export-general
   :version "24.4"
   :package-version '(Org . "8.0")
-  :type 'boolean)
+  :type 'boolean
+  :safe #'booleanp)
 
 (defcustom org-export-with-priority nil
   "Non-nil means include priority cookies in export.
 This option can also be set with the OPTIONS keyword,
 e.g. \"pri:t\"."
   :group 'org-export-general
-  :type 'boolean)
+  :type 'boolean
+  :safe #'booleanp)
 
 (defcustom org-export-with-properties nil
   "Non-nil means export contents of properties drawers.
@@ -578,7 +603,9 @@ e.g. \"prop:t\"."
 	  (const :tag "All properties" t)
 	  (const :tag "None" nil)
 	  (repeat :tag "Selected properties"
-		  (string :tag "Property name"))))
+		  (string :tag "Property name")))
+  :safe (lambda (x) (or (booleanp x)
+			(and (listp x) (cl-every #'stringp x)))))
 
 (defcustom org-export-with-section-numbers t
   "Non-nil means add section numbers to headlines when exporting.
@@ -589,7 +616,8 @@ headlines whose relative level is higher or equal to n.
 This option can also be set with the OPTIONS keyword,
 e.g. \"num:t\"."
   :group 'org-export-general
-  :type 'boolean)
+  :type 'boolean
+  :safe #'booleanp)
 
 (defcustom org-export-select-tags '("export")
   "Tags that select a tree for export.
@@ -601,7 +629,8 @@ tagging it with one of the `org-export-exclude-tags'.
 
 This option can also be set with the SELECT_TAGS keyword."
   :group 'org-export-general
-  :type '(repeat (string :tag "Tag")))
+  :type '(repeat (string :tag "Tag"))
+  :safe (lambda (x) (and (listp x) (cl-every #'stringp x))))
 
 (defcustom org-export-with-smart-quotes nil
   "Non-nil means activate smart quotes during export.
@@ -616,7 +645,8 @@ E.g., you can load Babel for french like this:
   :group 'org-export-general
   :version "24.4"
   :package-version '(Org . "8.0")
-  :type 'boolean)
+  :type 'boolean
+  :safe #'booleanp)
 
 (defcustom org-export-with-special-strings t
   "Non-nil means interpret \"\\-\", \"--\" and \"---\" for export.
@@ -633,7 +663,8 @@ When this option is turned on, these strings will be exported as:
 This option can also be set with the OPTIONS keyword,
 e.g. \"-:nil\"."
   :group 'org-export-general
-  :type 'boolean)
+  :type 'boolean
+  :safe #'booleanp)
 
 (defcustom org-export-with-statistics-cookies t
   "Non-nil means include statistics cookies in export.
@@ -642,7 +673,8 @@ e.g. \"stat:nil\""
   :group 'org-export-general
   :version "24.4"
   :package-version '(Org . "8.0")
-  :type 'boolean)
+  :type 'boolean
+  :safe #'booleanp)
 
 (defcustom org-export-with-sub-superscripts t
   "Non-nil means interpret \"_\" and \"^\" for export.
@@ -679,7 +711,8 @@ frequently in plain text."
   :type '(choice
 	  (const :tag "Interpret them" t)
 	  (const :tag "Curly brackets only" {})
-	  (const :tag "Do not interpret them" nil)))
+	  (const :tag "Do not interpret them" nil))
+  :safe (lambda (x) (memq x '(t nil {}))))
 
 (defcustom org-export-with-toc t
   "Non-nil means create a table of contents in exported files.
@@ -697,7 +730,9 @@ e.g. \"toc:nil\" or \"toc:3\"."
   :type '(choice
 	  (const :tag "No Table of Contents" nil)
 	  (const :tag "Full Table of Contents" t)
-	  (integer :tag "TOC to level")))
+	  (integer :tag "TOC to level"))
+  :safe (lambda (x) (or (booleanp x)
+			(integerp x))))
 
 (defcustom org-export-with-tables t
   "Non-nil means export tables.
@@ -706,7 +741,8 @@ e.g. \"|:nil\"."
   :group 'org-export-general
   :version "24.4"
   :package-version '(Org . "8.0")
-  :type 'boolean)
+  :type 'boolean
+  :safe #'booleanp)
 
 (defcustom org-export-with-tags t
   "If nil, do not export tags, just remove them from headlines.
@@ -721,7 +757,8 @@ e.g. \"tags:nil\"."
   :type '(choice
 	  (const :tag "Off" nil)
 	  (const :tag "Not in TOC" not-in-toc)
-	  (const :tag "On" t)))
+	  (const :tag "On" t))
+  :safe (lambda (x) (memq x '(t nil not-in-toc))))
 
 (defcustom org-export-with-tasks t
   "Non-nil means include TODO items for export.
@@ -742,7 +779,10 @@ e.g. \"tasks:nil\"."
 	  (const :tag "Not-done tasks" todo)
 	  (const :tag "Only done tasks" done)
 	  (repeat :tag "Specific TODO keywords"
-		  (string :tag "Keyword"))))
+		  (string :tag "Keyword")))
+  :safe (lambda (x) (or (memq x '(nil t todo done))
+			(and (listp x)
+			     (cl-every #'stringp x)))))
 
 (defcustom org-export-with-title t
   "Non-nil means print title into the exported file.
@@ -751,14 +791,16 @@ e.g. \"title:nil\"."
   :group 'org-export-general
   :version "25.1"
   :package-version '(Org . "8.3")
-  :type 'boolean)
+  :type 'boolean
+  :safe #'booleanp)
 
 (defcustom org-export-time-stamp-file t
   "Non-nil means insert a time stamp into the exported file.
 The time stamp shows when the file was created.  This option can
 also be set with the OPTIONS keyword, e.g. \"timestamp:nil\"."
   :group 'org-export-general
-  :type 'boolean)
+  :type 'boolean
+  :safe #'booleanp)
 
 (defcustom org-export-with-timestamps t
   "Non nil means allow timestamps in export.
@@ -780,7 +822,8 @@ This option can also be set with the OPTIONS keyword, e.g.
 	  (const :tag "All timestamps" t)
 	  (const :tag "Only active timestamps" active)
 	  (const :tag "Only inactive timestamps" inactive)
-	  (const :tag "No timestamp" nil)))
+	  (const :tag "No timestamp" nil))
+  :safe (lambda (x) (memq x '(t nil active inactive))))
 
 (defcustom org-export-with-todo-keywords t
   "Non-nil means include TODO keywords in export.
@@ -832,7 +875,12 @@ HTML code while every other back-end will ignore it."
   :package-version '(Org . "8.0")
   :type '(repeat
 	  (cons (string :tag "Shortcut")
-		(string :tag "Back-end"))))
+		(string :tag "Back-end")))
+  :safe (lambda (x)
+	  (and (listp x)
+	       (cl-every #'consp x)
+	       (cl-every #'stringp (mapcar #'car x))
+	       (cl-every #'stringp (mapcar #'cdr x)))))
 
 (defcustom org-export-coding-system nil
   "Coding system for the exported file."