(tar-mode-write-file): Protect from null tar-header-offset.

1 files changed, 4 insertions, 1 deletions

diff --git a/lisp/tar-mode.el b/lisp/tar-mode.el
index c2d2033a641..dd12d9bbca9 100644
--- a/lisp/tar-mode.el
+++ b/lisp/tar-mode.el
@@ -1205,7 +1205,10 @@ Leaves the region wide."
         ;; Doing this here confuses things - the region gets left too wide!
         ;; I suppose this is run in a context where changing the buffer is bad.
         ;; (tar-pad-to-blocksize)
-        (write-region tar-header-offset (point-max) buffer-file-name nil t)
+        ;; tar-header-offset turns out to be null for files fetched with W3,
+        ;; at least.
+        (write-region (or tar-header-offset (point-min)) (point-max)
+                      buffer-file-name nil t)
         (tar-clear-modification-flags)
         (set-buffer-modified-p nil))
     (narrow-to-region 1 tar-header-offset))