emacs: Work around gnus-inhibit-images bug in mm-shr

Emacs 24's mm-shr HTML email renderer fails to load gnus-art before
referencing gnus-inhibit-images, resulting in a void-variable error
when notmuch attempts to render an HTML email with inline images.
This works around this bug by advising mm-shr to load gnus-art.

mm-shr is the only function outside of gnus-art itself that references
gnus-inhibit-images, so this workaround should be correct.  If this
ever changes, hopefully they will have fixed this bug upstream first.

This fixes the "Rendering HTML mail with images" test for Emacs 24.

diff --git a/emacs/notmuch-lib.el b/emacs/notmuch-lib.el
index 20d990dfc19ab73d2c49e6c2436af19c161ac7bd..69867ada9a6a68ff7cb7851e25cbb7b232c1d10c 100644 (file)
--- a/emacs/notmuch-lib.el
+++ b/emacs/notmuch-lib.el
@@ -254,6 +254,19 @@ the given type."
   (or (plist-get part :content)
       (notmuch-get-bodypart-internal (notmuch-id-to-query (plist-get msg :id)) nth process-crypto)))
 
+;; Workaround: The call to `mm-display-part' below triggers a bug in
+;; Emacs 24 if it attempts to use the shr renderer to display an HTML
+;; part with images in it (demonstrated in 24.1 and 24.2 on Debian and
+;; Fedora 17, though unreproducable in other configurations).
+;; `mm-shr' references the variable `gnus-inhibit-images' without
+;; first loading gnus-art, which defines it, resulting in a
+;; void-variable error.  Hence, we advise `mm-shr' to ensure gnus-art
+;; is loaded.
+(if (>= emacs-major-version 24)
+    (defadvice mm-shr (before load-gnus-arts activate)
+      (require 'gnus-art nil t)
+      (ad-disable-advice 'mm-shr 'before 'load-gnus-arts)))
+
 (defun notmuch-mm-display-part-inline (msg part nth content-type process-crypto)
   "Use the mm-decode/mm-view functions to display a part in the
 current buffer, if possible."