From fbc8993e32794a3f7dde5220a2ff683657bf7dab Mon Sep 17 00:00:00 2001
From: NeilBrown <neil@brown.name>
Date: Fri, 12 May 2023 19:10:19 +1000
Subject: [PATCH] notmuch: handle display of alternatives that are multipart.

An alternative can be multipart, e.g. multipart/related.
In that case it won't be the last segment of the path which
says "alternative".  We have to look earlier.

Signed-off-by: NeilBrown <neil@brown.name>
---
 DOC/TODO.md              |  2 +-
 python/module-notmuch.py | 16 +++++++++++++---
 2 files changed, 14 insertions(+), 4 deletions(-)

diff --git a/DOC/TODO.md b/DOC/TODO.md
index 292164da..68753f6b 100644
--- a/DOC/TODO.md
+++ b/DOC/TODO.md
@@ -35,7 +35,7 @@ Bugs to be fixed
 - [X] line break in <a hseq="2"\nhref=.....   isn't handled.
 - [X] utf-8 output from w3m gets displayed a bytes!!
        This is actually buggy spam which claims not to be utf-8
-- [ ] email: when alternative/1 is related and text/html, is isn't
+- [X] email: when alternative/1 is related and text/html, is isn't
        displayed by default.
 - [X] email: when a convertion pane is created on a 'text' component
       it should be given utf-8 and not have to use "bytes" like html does.
diff --git a/python/module-notmuch.py b/python/module-notmuch.py
index 6e58442a..6a967563 100644
--- a/python/module-notmuch.py
+++ b/python/module-notmuch.py
@@ -3182,11 +3182,21 @@ class notmuch_message_view(edlib.Pane):
             # know which is invisible when we get to the end.
             # So record the visibility of each group of alternatives
             # now, and the walk through again setting visibility.
+            # An alternative itself may be multi-part, typically
+            # multipart/related.  In this case we only look at
+            # whether we can handle the type of the first part.
             p = path.split(',')
-            if p[-1].startswith("alternative:"):
+            i = len(p)-1
+            while (i > 0 and p[i].endswith(":0") and
+                   not p[i].startswith("alternative:")):
+                # Might be the first part of a multi-path alternative,
+                # look earlier in the path
+                i -= 1
+            edlib.LOG("consider", p, i, )
+            if p[i].startswith("alternative:"):
                 # this is one of several - can we handle it?
-                group = ','.join(p[:-1])
-                this = p[-1][12:]
+                group = ','.join(p[:i])
+                this = p[i][12:]
                 if type in ['text/plain', 'text/calendar', 'text/rfc822-headers',
                             'message/rfc822']:
                     choose[group] = this
-- 
2.39.5