autoload.el fix for bug#10049

* lisp/emacs-lisp/autoload.el (autoload-generate-file-autoloads):
Ignore buffer-local generated-autoload-file if it is the same
as the global value.

2 files changed, 13 insertions, 0 deletions

diff --git a/lisp/ChangeLog b/lisp/ChangeLog
index 38efb16bd80..45a115ec566 100644
--- a/lisp/ChangeLog
+++ b/lisp/ChangeLog
@@ -1,3 +1,9 @@
+2011-11-17  Glenn Morris  <rgm@gnu.org>
+
+        * emacs-lisp/autoload.el (autoload-generate-file-autoloads):
+        Ignore buffer-local generated-autoload-file if it is the same
+        as the global value.  (Bug#10049)
+
 2011-11-17  Juanma Barranquero  <lekktu@gmail.com>
 
         * textmodes/reftex-toc.el (reftex-toc-return-marker, reftex-toc-help)
diff --git a/lisp/emacs-lisp/autoload.el b/lisp/emacs-lisp/autoload.el
index 6d5067151d3..b3ac23b2b76 100644
--- a/lisp/emacs-lisp/autoload.el
+++ b/lisp/emacs-lisp/autoload.el
@@ -514,6 +514,13 @@ Return non-nil if and only if FILE adds no autoloads to OUTFILE
             (let ((secondary-autoloads-file-buf
                    (if (local-variable-p 'generated-autoload-file)
                        (current-buffer))))
+              ;; Ignore a buffer-local setting if it points to the
+              ;; global value.  Otherwise we end up writing a mix of md5s
+              ;; and time-stamps to the global file.  (Bug#10049)
+              (and secondary-autoloads-file-buf
+                   outfile
+                   (not otherbuf)
+                   (setq secondary-autoloads-file-buf nil))
               (with-current-buffer (marker-buffer output-start)
                 (save-excursion
                   ;; Insert the section-header line which lists the file name