(tar-extract): Base the name of the subfile buffer

on the name of the tar buffer.  Verify that the existing buffer is
visiting the same subfile.

1 files changed, 11 insertions, 9 deletions

diff --git a/lisp/tar-mode.el b/lisp/tar-mode.el
index 5c5bdae4170..264bc37f2e6 100644
--- a/lisp/tar-mode.el
+++ b/lisp/tar-mode.el
@@ -678,19 +678,23 @@ appear on disk when you save the tar-file's buffer."
          (end (+ start size)))
     (let* ((tar-buffer (current-buffer))
            (tar-buffer-multibyte enable-multibyte-characters)
-           (tarname (if (buffer-file-name)
-                        (file-name-nondirectory (buffer-file-name))
-                      (buffer-name)))
+           (tarname (buffer-name))
            (bufname (concat (file-name-nondirectory name)
                             " ("
                             tarname
                             ")"))
            (read-only-p (or buffer-read-only view-p))
            (buffer (get-buffer bufname))
-           (just-created nil))
-      (if buffer
+           (just-created nil)
+           (new-buffer-file-name (expand-file-name
+                                  ;; `:' is not allowed on Windows
+                                  (concat tarname "!" name))))
+      (if (and buffer
+               ;; Check that the buffer is visiting the same file
+               (equal (buffer-file-name buffer) new-buffer-file-name))
           nil
-        (setq buffer (get-buffer-create bufname))
+        (setq buffer (generate-new-buffer bufname))
+        (setq bufname (buffer-name buffer))
         (setq just-created t)
         (unwind-protect
             (progn
@@ -706,9 +710,7 @@ appear on disk when you save the tar-file's buffer."
                       (set-buffer-multibyte t))
                   (insert-buffer-substring tar-buffer start end))
                 (goto-char (point-min))
-                (setq buffer-file-name
-                      ;; `:' is not allowed on Windows
-                      (expand-file-name (concat tarname "!" name)))
+                (setq buffer-file-name new-buffer-file-name)
                 (setq buffer-file-truename
                       (abbreviate-file-name buffer-file-name))
                 ;; We need to mimic the parts of insert-file-contents