From: Noam Postavsky <npostavs@gmail.com>
Date: Fri, 2 Jun 2017 03:09:36 +0000 (-0400)
Subject: Fix infloop in uncomment-region-default (Bug#27112)
X-Git-Tag: emacs-26.0.90~520^2~11^2~11
X-Git-Url: http://git.eshelyaron.com/gitweb/?a=commitdiff_plain;h=2a9d7394e36524c84fcbd61e4058b9fb89e3cc2b;p=emacs.git

Fix infloop in uncomment-region-default (Bug#27112)

When `comment-continue' has only blanks, `comment-padright' produces a
regexp that matches the empty string, so `uncomment-region-default'
will loop infinitely.
* lisp/newcomment.el (comment-padright): Only return a regexp if STR
has nonblank characters.
---

diff --git a/lisp/newcomment.el b/lisp/newcomment.el
index 4b261c34c65..118549f421c 100644
--- a/lisp/newcomment.el
+++ b/lisp/newcomment.el
@@ -815,7 +815,7 @@ N defaults to 0.
 If N is `re', a regexp is returned instead, that would match
 the string for any N."
   (setq n (or n 0))
-  (when (and (stringp str) (not (string= "" str)))
+  (when (and (stringp str) (string-match "\\S-" str))
     ;; Separate the actual string from any leading/trailing padding
     (string-match "\\`\\s-*\\(.*?\\)\\s-*\\'" str)
     (let ((s (match-string 1 str))	;actual string