Display all parts of a multipart/alternative message (or message-part)
if no alternative_preference matches any of the alternative mimetypes.

E.g. if a message is multipart/alternative with options text/plain and
text/html, and the alternative_preference is ['application/pdf'], no
preference option matches any of the parts. This patch would just
display both parts.

Better configuration is to have '*/*' as an option in your
alternative_preference, e.g. ['text/plain', 'text/*', '*/*'], so that
there is always a catch-all.
---
 vim/notmuch.vim | 19 ++++++++++++++++++-
 1 file changed, 18 insertions(+), 1 deletion(-)

diff --git a/vim/notmuch.vim b/vim/notmuch.vim
index 5cb8d20..da747eb 100644
--- a/vim/notmuch.vim
+++ b/vim/notmuch.vim
@@ -337,7 +337,24 @@ ruby << EOF
 			while parts.any?(&:multipart?)
 				parts = parts.collect do |part|
 					if part.multipart?
-						part.parts
+						if part.mime_type == "multipart/alternative"
+							case alternative_display
+							when "best-only"
+								alternative_preference.each.collect do |mime_type|
+									part.parts.find { |p| File.fnmatch(mime_type, p.mime_type) }
+								end.reject(&:nil?).first || part.parts
+							when "best-sort"
+								part.parts.sort_by do |p|
+									alternative_preference.collect.with_index do |mime_type, i|
+										(File.fnmatch(mime_type, p.mime_type) ? 0 : 1) << i
+									end.reduce(:+)
+								end
+							when "verbatim"
+								part.parts
+							end
+						else
+							part.parts
+						end
 					else
 						part
 					end
-- 
2.7.3