emacs-28 c09ad0c: Fix the bug with duplicate entries in xref output

[Dmitry Gutov]

branch: emacs-28
commit c09ad0cabde922374c1a34350595a3141ab7f806
Author: Dmitry Gutov <dgutov@yandex.ru>
Commit: Dmitry Gutov <dgutov@yandex.ru>

    Fix the bug with duplicate entries in xref output
    
    * lisp/progmodes/etags.el (xref-backend-definitions): Make sure to
    save the changed intermediate value of the list (bug#52734).
---
 lisp/progmodes/etags.el | 17 +++++++++--------
 1 file changed, 9 insertions(+), 8 deletions(-)

diff --git a/lisp/progmodes/etags.el b/lisp/progmodes/etags.el
index f53b09d..a63c3f3 100644
--- a/lisp/progmodes/etags.el
+++ b/lisp/progmodes/etags.el
@@ -2084,14 +2084,15 @@ file name, add `tag-partial-file-name-match-p' to the 
list value.")
         (definitions (etags--xref-find-definitions symbol))
         same-file-definitions)
     (when (and etags-xref-prefer-current-file file)
-      (cl-delete-if
-       (lambda (definition)
-         (when (equal file
-                      (xref-location-group
-                       (xref-item-location definition)))
-           (push definition same-file-definitions)
-           t))
-       definitions)
+      (setq definitions
+            (cl-delete-if
+             (lambda (definition)
+               (when (equal file
+                            (xref-location-group
+                             (xref-item-location definition)))
+                 (push definition same-file-definitions)
+                 t))
+             definitions))
       (setq definitions (nconc (nreverse same-file-definitions)
                                definitions)))
     definitions))