Make vc-deduce-fileset do the right thing in derived buffers.

2 files changed, 13 insertions, 1 deletions

diff --git a/lisp/ChangeLog b/lisp/ChangeLog
index 524dd2923f8..21fc108c895 100644
--- a/lisp/ChangeLog
+++ b/lisp/ChangeLog
@@ -1,3 +1,8 @@
+2008-05-14  Eric S. Raymond  <esr@snark.thyrsus.com>
+
+        * vc.el (vc-deduce-fileset): Do the right thing when visting a
+        buffer (say, a log buffer or diff buffer) with a vc-dir buffer as parent.
+
 2008-05-14  John Paul Wallington  <jpw@pobox.com>
 
         * international/mule.el (convert-define-charset-argument): Remove
diff --git a/lisp/vc.el b/lisp/vc.el
index 2795912dca1..d2791587fc3 100644
--- a/lisp/vc.el
+++ b/lisp/vc.el
@@ -982,12 +982,19 @@ Within directories, only files already under version control are noticed."
       (push node flattened))
     (nreverse flattened)))
 
+(defun vc-derived-from-dir-mode (&optional buffer)
+  "Are we in a VC-directory buffer, or do we have one as an ancestor?"
+  (let ((buffer (or buffer (current-buffer))))
+    (cond ((derived-mode-p 'vc-dir-mode) t)
+          (vc-parent-buffer (vc-derived-from-dir-mode vc-parent-buffer))
+          (t nil))))
+
 (defun vc-deduce-fileset (&optional observer)
   "Deduce a set of files and a backend to which to apply an operation and
 the common state of the fileset.  Return (BACKEND . FILESET)."
   (let* ((fileset (vc-dispatcher-selection-set observer))
          ;; FIXME: Store the backend in a buffer-local variable.
-         (backend (if (derived-mode-p 'vc-dir-mode)
+         (backend (if (vc-derived-from-dir-mode (current-buffer))
                       (vc-responsible-backend default-directory)
                     (assert (and (= 1 (length fileset))
                                  (not (file-directory-p (car fileset)))))