Test comment-multi-line = nil auto fill case too

* test/lisp/progmodes/js-tests.el (js-mode-auto-fill): Test with
`comment-multi-line' both nil and non-nil.
* lisp/newcomment.el (comment-multi-line): Mark safe if it's a
boolean.
* etc/NEWS: Mention that `js-mode' now sets `comment-multi-line'.

1 files changed, 12 insertions, 10 deletions

diff --git a/test/lisp/progmodes/js-tests.el b/test/lisp/progmodes/js-tests.el
index d61f084e0df..99f5898525b 100644
--- a/test/lisp/progmodes/js-tests.el
+++ b/test/lisp/progmodes/js-tests.el
@@ -89,16 +89,18 @@ if (!/[ (:,='\"]/.test(value)) {
 (ert-deftest js-mode-auto-fill ()
   (with-temp-buffer
     (js-mode)
-    (setq fill-column 70)
-    (insert "/* ")
-    (dotimes (_ 16)
-      (insert "test "))
-    (do-auto-fill)
-    ;; The bug is that, after auto-fill, the second line starts with
-    ;; "/*", whereas it should start with " * ".
-    (goto-char (point-min))
-    (forward-line)
-    (should (looking-at " \\* test"))))
+    (let ((fill-column 10)
+          (comment-multi-line t))
+      (insert "/* test test")
+      (do-auto-fill)
+      ;; Filling should continue the multi line comment.
+      (should (equal (buffer-string) "/* test\n * test"))
+      (erase-buffer)
+      (insert "/* test test")
+      (setq comment-multi-line nil)
+      (do-auto-fill)
+      ;; Filling should start a new comment on the next line.
+      (should (equal (buffer-string) "/* test */\n/* test")))))
 
 (ert-deftest js-mode-regexp-syntax-bug-25529 ()
   (dolist (regexp-contents '("[^[]"