* lisp/shell.el (shell--unquote&requote-argument): Match data misuse

* lisp/shell.el (shell--unquote&requote-argument): Fix
off-by-one thinko.  Don't use match data after a failed string-match.

2 files changed, 40 insertions, 3 deletions

diff --git a/lisp/shell.el b/lisp/shell.el
index 1f019f20f3a..34bd77282ab 100644
--- a/lisp/shell.el
+++ b/lisp/shell.el
@@ -384,11 +384,15 @@ Thus, this does not include the shell's current directory.")
        ((eq (aref qstr match) ?\") (setq dquotes (not dquotes)))
        ((eq (aref qstr match) ?\')
         (cond
+         ;; Treat single quote as text if inside double quotes.
          (dquotes (funcall push "'" (match-end 0)))
-         ((< match (1+ (length qstr)))
+         ((< (1+ match) (length qstr))
           (let ((end (string-match "'" qstr (1+ match))))
-            (funcall push (substring qstr (1+ match) end)
-                     (or end (length qstr)))))
+            (unless end
+              (setq end (length qstr))
+              (set-match-data (list match (length qstr))))
+            (funcall push (substring qstr (1+ match) end) end)))
+         ;; Ignore if at the end of string.
          (t nil)))
        (t (error "Unexpected case in shell--unquote&requote-argument!")))
       (setq qpos (match-end 0)))
diff --git a/test/lisp/shell-tests.el b/test/lisp/shell-tests.el
new file mode 100644
index 00000000000..be8f7d5c139
--- /dev/null
+++ b/test/lisp/shell-tests.el
@@ -0,0 +1,33 @@
+;;; shell-tests.el  -*- lexical-binding:t -*-
+
+;; Copyright (C) 2010-2016 Free Software Foundation, Inc.
+
+;; This file is part of GNU Emacs.
+
+;; GNU Emacs is free software: you can redistribute it and/or modify
+;; it under the terms of the GNU General Public License as published by
+;; the Free Software Foundation, either version 3 of the License, or
+;; (at your option) any later version.
+
+;; GNU Emacs is distributed in the hope that it will be useful,
+;; but WITHOUT ANY WARRANTY; without even the implied warranty of
+;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+;; GNU General Public License for more details.
+
+;; You should have received a copy of the GNU General Public License
+;; along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.
+
+;;; Commentary:
+
+;; Tests for comint and related modes.
+
+;;; Code:
+
+(require 'shell)
+(require 'ert)
+
+(ert-deftest shell-tests-unquote-1 ()
+  "Test problem found by Filipp Gunbin in emacs-devel."
+  (should (equal (car (shell--unquote&requote-argument "te'st" 2)) "test")))
+
+;;; shell-tests.el ends here