emacs-29 fdc1a12ed1a: Fix "vc-print-log does not erase buffer" and associated problems

[Dmitry Gutov]

branch: emacs-29
commit fdc1a12ed1a2ceaebf21ec68752e85dd4527ceab
Author: Dmitry Gutov <dmitry@gutov.dev>
Commit: Dmitry Gutov <dmitry@gutov.dev>

    Fix "vc-print-log does not erase buffer" and associated problems
    
    * lisp/vc/vc.el (vc-deduce-fileset): Make sure to retain the
    buffer switch (if it did), bug#63949.
---
 lisp/vc/vc.el | 13 +++++++++----
 1 file changed, 9 insertions(+), 4 deletions(-)

diff --git a/lisp/vc/vc.el b/lisp/vc/vc.el
index 1144a23f317..410fe5c01e1 100644
--- a/lisp/vc/vc.el
+++ b/lisp/vc/vc.el
@@ -1121,10 +1121,15 @@ possible values of STATE are explained in `vc-state', 
and MODEL in
 the returned list.
 
 BEWARE: this function may change the current buffer."
-  (with-current-buffer (or (buffer-base-buffer) (current-buffer))
-    (vc-deduce-fileset-1 not-state-changing
-                         allow-unregistered
-                         state-model-only-files)))
+  (let (new-buf res)
+    (with-current-buffer (or (buffer-base-buffer) (current-buffer))
+      (setq res
+            (vc-deduce-fileset-1 not-state-changing
+                                 allow-unregistered
+                                 state-model-only-files))
+      (setq new-buf (current-buffer)))
+    (set-buffer new-buf)
+    res))
 
 (defun vc-deduce-fileset-1 (not-state-changing
                             allow-unregistered