cperl-mode.el: Optionally treat trailing text as comment

* lisp/progmodes/cperl-mode.el (cperl-fontify-trailer): New
customization variable.  With a value of 'comment, cperl-mode
treats trailing text after after __END__ and __DATA__ as comment,
like perl-mode does (Bug#66161).
(cperl-find-pods-heres): Treat trailing text after __END__ and
__DATA__ according to the customization variable
`cperl-fontify-trailer'.

* test/lisp/progmodes/cperl-mode-tests.el (cperl-test-bug-66161):
New test, verifying the changed behavior if the custom variable is
set to 'comment.

* test/lisp/progmodes/cperl-mode-resources/cperl-bug-66161.pl: New
resource file, source code from the corresponding bug report.

lisp/progmodes/cperl-mode.el

@@ -550,6 +550,18 @@ This way enabling/disabling of menu items is more correct."
   :version "29.1")
 ;;;###autoload(put 'cperl-file-style 'safe-local-variable 'stringp)
 
+(defcustom cperl-fontify-trailer
+  'perl-code
+  "How to fontify text after an \"__END__\" or \"__DATA__\" token.
+If \"perl-code\", treat as Perl code for fontification, and
+examine for imenu entries.  Use this setting if you have trailing
+POD documentation, or for modules which use AutoLoad or
+AutoSplit.  If \"comment\", treat as comment, and do not look for
+imenu entries."
+  :type '(choice (const perl-code)
+		 (const comment))
+  :group 'cperl-faces)
+
 (defcustom cperl-ps-print-face-properties
   '((font-lock-keyword-face		nil nil		bold shadow)
     (font-lock-variable-name-face	nil nil		bold)
@@ -4913,8 +4925,9 @@ recursive calls in starting lines of here-documents."
 	       ;; 1+6+2+1+1+6+1+1=19 extra () before this:
 	       ;; "__\\(END\\|DATA\\)__"
 	       ((match-beginning 20)	; __END__, __DATA__
-		(setq bb (match-end 0))
-		;; (put-text-property b (1+ bb) 'syntax-type 'pod) ; Cheat
+                (if (eq cperl-fontify-trailer 'perl-code)
+		    (setq bb (match-end 0))
+                  (setq bb (point-max)))
 		(cperl-commentify b bb nil)
 		(setq end t))
 	       ;; "\\\\\\(['`\"($]\\)"

test/lisp/progmodes/cperl-mode-resources/cperl-bug-66161.pl

@@ -0,0 +1,13 @@
+#!/usr/bin/perl
+
+use strict;
+use warnings;
+
+print("Hello World\n");
+
+__END__
+
+TODO:
+What's happening?
+
+It's all messed up.

test/lisp/progmodes/cperl-mode-tests.el

@@ -1403,6 +1403,20 @@ beginning with `cperl-test-unicode`."
                          (cdr (assoc (match-string-no-properties 1)
                                      faces)))))))))
 
+(ert-deftest cperl-test-bug-66161 ()
+  "Verify that text after \"__END__\" is fontified as comment.
+For `cperl-mode', this needs the custom variable
+`cperl-fontify-trailer' to be set to `comment'.  Per default,
+cperl-mode fontifies text after the delimiter as Perl code."
+  (with-temp-buffer
+    (insert-file-contents (ert-resource-file "cperl-bug-66161.pl"))
+    (setq cperl-fontify-trailer 'comment)
+    (funcall cperl-test-mode)
+    (font-lock-ensure)
+    (search-forward "TODO")             ; leaves point before the colon
+    (should (equal (get-text-property (point) 'face)
+                   font-lock-comment-face))))
+
 (ert-deftest test-indentation ()
   (ert-test-erts-file (ert-resource-file "cperl-indents.erts")))