bug#32475: 27.0.50; Multiple log-view-mode buffers

[Juri Linkov]

To support the ability to create multiple *vc-change-log* buffers
with customization like

  (add-hook 'log-view-mode-hook 'rename-uniquely)

vc-log-internal-common needs an improvement to remember and reuse
the buffer object, instead of searching the same buffer by name:

diff --git a/lisp/vc/vc.el b/lisp/vc/vc.el
index b2bedfae93..487594b2d5 100644
--- a/lisp/vc/vc.el
+++ b/lisp/vc/vc.el
@@ -2268,11 +2268,11 @@ vc-log-internal-common
                               setup-buttons-func
                               goto-location-func
                               rev-buff-func)
-  (let (retval)
-    (with-current-buffer (get-buffer-create buffer-name)
+  (let (retval (buffer (get-buffer-create buffer-name)))
+    (with-current-buffer buffer
       (set (make-local-variable 'vc-log-view-type) type))
     (setq retval (funcall backend-func backend buffer-name type files))
-    (with-current-buffer (get-buffer buffer-name)
+    (with-current-buffer buffer
       (let ((inhibit-read-only t))
        ;; log-view-mode used to be called with inhibit-read-only bound
        ;; to t, so let's keep doing it, just in case.
@@ -2283,7 +2283,7 @@ vc-log-internal-common
             rev-buff-func)))
     ;; Display after setting up major-mode, so display-buffer-alist can know
     ;; the major-mode.
-    (pop-to-buffer buffer-name)
+    (pop-to-buffer buffer)
     (vc-run-delayed
      (let ((inhibit-read-only t))
        (funcall setup-buttons-func backend files retval)