Improve handling of the first Git revision

* lisp/vc/log-view.el (log-view-toggle-entry-display): When
there's no next entry, delete until the end of the buffer.
(log-view-end-of-defun-1): Stop at eob.

* lisp/vc/vc-annotate.el
(vc-annotate-show-diff-revision-at-line-internal): Don't give up
when previous-revision is nil.

* lisp/vc/vc-git.el (vc-git-expanded-log-entry): End the arguments
with `--' to avoid ambiguity.
(vc-git-annotate-extract-revision-at-line): Exclude `^' from the
returned revision string.
(vc-git-annotate-time): Expect `^' before the first revision.

* lisp/vc/vc-git.el (vc-git-diff): Diff against an empty tree if
REV1 is nil, and REV2 is not.

* lisp/vc/vc.el: Update the description of the `diff' function.

1 files changed, 9 insertions, 11 deletions

diff --git a/lisp/vc/vc-annotate.el b/lisp/vc/vc-annotate.el
index d369c90915a..3a50c9b6a2d 100644
--- a/lisp/vc/vc-annotate.el
+++ b/lisp/vc/vc-annotate.el
@@ -582,17 +582,15 @@ the file in question, search for the log entry required and move point."
 	(setq prev-rev
 	      (vc-call-backend vc-annotate-backend 'previous-revision
                                (if filediff fname nil) rev))
-	(if (not prev-rev)
-	    (message "Cannot diff from any revision prior to %s" rev)
-          (vc-diff-internal
-           t
-           ;; The value passed here should follow what
-           ;; `vc-deduce-fileset' returns.
-           (list vc-annotate-backend
-                 (if filediff
-                     (list fname)
-                   nil))
-           prev-rev rev))))))
+	(vc-diff-internal
+         t
+         ;; The value passed here should follow what
+         ;; `vc-deduce-fileset' returns.
+         (list vc-annotate-backend
+               (if filediff
+                   (list fname)
+                 nil))
+         prev-rev rev)))))
 
 (defun vc-annotate-show-diff-revision-at-line ()
   "Visit the diff of the revision at line from its previous revision."