Rework xref-query-replace-in-results

* lisp/progmodes/xref.el (xref-query-replace-in-results): Collect
all xrefs from the buffer first, then delegate most of the
processing to the value returned by xref--buf-pairs-iterator.
(xref--buf-pairs-iterator): New function.  Return an "iterator"
which partitions returned markers into buffers, and only processes
markers from one buffer at a time.  When an xref is out of date,
skip it with a message instead of signaling error (bug#23284).
(xref--outdated-p): Extract from xref--buf-pairs-iterator.  Trim
CR from both strings before comparing.
(xref--query-replace-1): Remove the variable current-buf, no need
to track it anymore.  Simplify the filter-predicate and search
functions accordingly.  Iterate over buffer-markers pairs returned
by the iterator, and call `perform-replace' for each of them.  Use
multi-query-replace-map (bug#23284).  Use `switch-to-buffer' every
time after the first, in order not to jump between windows.

* test/automated/xref-tests.el
(xref--buf-pairs-iterator-groups-markers-by-buffers-1)
(xref--buf-pairs-iterator-groups-markers-by-buffers-2)
(xref--buf-pairs-iterator-cleans-up-markers): New tests.

1 files changed, 29 insertions, 0 deletions

diff --git a/test/automated/xref-tests.el b/test/automated/xref-tests.el
index b288e2d7584..079b196aa8b 100644
--- a/test/automated/xref-tests.el
+++ b/test/automated/xref-tests.el
@@ -60,3 +60,32 @@
     (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))))))))