Merge from origin/emacs-25

50650cb Doc fixes for fclist and grep
5e814e0 Minor doc fixes for quoting
3347a73 `nreverse' the marker pairs list
1a4127d Use save-excursion in xref-location-marker more
ab3ba91 shell-quote-argument DIR when appropriate
922c7a3 Rework xref-query-replace-in-results
3fe3510 * lisp/replace.el (query-replace-read-from): Use minibuffer-w...
0932b94 Fix todo-mode bug involving archived items (bug#23447)
e68ad1f ; * etc/NEWS: Tiny edit. (Bug#23432)
adc80b7 ; * test/automated/xref-tests.el: Add copyright and license.
4d8fd9c Handle "empty line" regexp in xref searches
f559b37 Add tests for xref-collect-matches
6428aa0 Use grep-find-ignored-directories instead of vc-directory-exc...
6f82d8e Clear buffer-undo-list when showing xrefs
c68a091 Note the quote translation in `message' in section "incompati...
52f86a7 * etc/NEWS: Mention (message "%s" (format ...)).
93703c5 (Common Keywords): Correct what missing :group means
79e5800 Improve documentation of Dired's 'A' and 'Q' commands
2ea2a2f Doc fixes for quoting
8544b98 posnp doc clarification
805204f Mention what a missing :group does
ec554d7 Fix documentation of dired-aux search/replace commands

test/automated/data/xref/file1.txt

@@ -0,0 +1,2 @@
+foo foo
+bar

test/automated/data/xref/file2.txt

@@ -0,0 +1,2 @@
+
+bar

test/automated/xref-tests.el

@@ -0,0 +1,91 @@
+;;; xref-tests.el --- tests for xref
+
+;; Copyright (C) 2016 Free Software Foundation, Inc.
+
+;; Author: Dmitry Gutov <dgutov@yandex.ru>
+
+;; 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:
+
+;;; Code:
+
+(require 'xref)
+(require 'cl-lib)
+
+(defvar xref-tests-data-dir
+  (expand-file-name "data/xref/"
+                    (file-name-directory (or load-file-name (buffer-file-name)))))
+
+(ert-deftest xref-collect-matches-finds-none-for-some-regexp ()
+  (should (null (xref-collect-matches "zzz" "*" xref-tests-data-dir nil))))
+
+(ert-deftest xref-collect-matches-finds-some-for-bar ()
+  (let* ((matches (xref-collect-matches "bar" "*" xref-tests-data-dir nil))
+         (locs (cl-sort (mapcar #'xref-item-location matches)
+                        #'string<
+                        :key #'xref-location-group)))
+    (should (= 2 (length matches)))
+    (should (string-match-p "file1\\.txt\\'" (xref-location-group (nth 0 locs))))
+    (should (string-match-p "file2\\.txt\\'" (xref-location-group (nth 1 locs))))))
+
+(ert-deftest xref-collect-matches-finds-two-matches-on-the-same-line ()
+  (let* ((matches (xref-collect-matches "foo" "*" xref-tests-data-dir nil))
+         (locs (mapcar #'xref-item-location matches)))
+    (should (= 2 (length matches)))
+    (should (string-match-p "file1\\.txt\\'" (xref-location-group (nth 0 locs))))
+    (should (string-match-p "file1\\.txt\\'" (xref-location-group (nth 1 locs))))
+    (should (equal 1 (xref-location-line (nth 0 locs))))
+    (should (equal 1 (xref-location-line (nth 1 locs))))
+    (should (equal 0 (xref-file-location-column (nth 0 locs))))
+    (should (equal 4 (xref-file-location-column (nth 1 locs))))))
+
+(ert-deftest xref-collect-matches-finds-an-empty-line-regexp-match ()
+  (let* ((matches (xref-collect-matches "^$" "*" xref-tests-data-dir nil))
+         (locs (mapcar #'xref-item-location matches)))
+    (should (= 1 (length matches)))
+    (should (string-match-p "file2\\.txt\\'" (xref-location-group (nth 0 locs))))
+    (should (equal 1 (xref-location-line (nth 0 locs))))
+    (should (equal 0 (xref-file-location-column (nth 0 locs))))))
+
+(ert-deftest xref--buf-pairs-iterator-groups-markers-by-buffers-1 ()
+  (let* ((xrefs (xref-collect-matches "foo" "*" xref-tests-data-dir nil))
+         (iter (xref--buf-pairs-iterator xrefs))
+         (cons (funcall iter :next)))
+    (should (null (funcall iter :next)))
+    (should (string-match "file1\\.txt\\'" (buffer-file-name (car cons))))
+    (should (= 2 (length (cdr cons))))))
+
+(ert-deftest xref--buf-pairs-iterator-groups-markers-by-buffers-2 ()
+  (let* ((xrefs (xref-collect-matches "bar" "*" xref-tests-data-dir nil))
+         (iter (xref--buf-pairs-iterator xrefs))
+         (cons1 (funcall iter :next))
+         (cons2 (funcall iter :next)))
+    (should (null (funcall iter :next)))
+    (should-not (equal (car cons1) (car cons2)))
+    (should (= 1 (length (cdr cons1))))
+    (should (= 1 (length (cdr cons2))))))
+
+(ert-deftest xref--buf-pairs-iterator-cleans-up-markers ()
+  (let* ((xrefs (xref-collect-matches "bar" "*" xref-tests-data-dir nil))
+         (iter (xref--buf-pairs-iterator xrefs))
+         (cons1 (funcall iter :next))
+         (cons2 (funcall iter :next)))
+    (funcall iter :cleanup)
+    (should (null (marker-position (car (nth 0 (cdr cons1))))))
+    (should (null (marker-position (cdr (nth 0 (cdr cons1))))))
+    (should (null (marker-position (car (nth 0 (cdr cons2))))))
+    (should (null (marker-position (cdr (nth 0 (cdr cons2))))))))