lib: choose oldest message when breaking reference loops

This preserves a sensible thread order

diff --git a/lib/thread.cc b/lib/thread.cc
index dbac002fd7130c4c7559dcf96fbb9b90bdab2487..e961c76bf37a8d3cbee2a4041da48ef92340b03a 100644 (file)
--- a/lib/thread.cc
+++ b/lib/thread.cc
@@ -390,20 +390,37 @@ _thread_add_matched_message (notmuch_thread_t *thread,
 static void
 _resolve_thread_relationships (notmuch_thread_t *thread)
 {
-    notmuch_message_node_t *node;
+    notmuch_message_node_t *node, *first_node;
     notmuch_message_t *message, *parent;
     const char *in_reply_to;
 
-    for (node = thread->message_list->head; node; node = node->next) {
+    first_node = thread->message_list->head;
+    if (! first_node)
+       return;
+
+    for (node = first_node->next; node; node = node->next) {
        message = node->message;
        in_reply_to = _notmuch_message_get_in_reply_to (message);
-       /*
-        * if we reach the end of the list without finding a top-level
-        * message, that means the thread is a cycle (or set of
-        * cycles) and any message can be considered top-level
-        */
-       if ((thread->toplevel_list->head || node->next) &&
-            in_reply_to && strlen (in_reply_to) &&
+       if (in_reply_to && strlen (in_reply_to) &&
+           g_hash_table_lookup_extended (thread->message_hash,
+                                         in_reply_to, NULL,
+                                         (void **) &parent))
+           _notmuch_message_add_reply (parent, message);
+       else
+           _notmuch_message_list_add_message (thread->toplevel_list, message);
+    }
+
+    /*
+     * if we reach the end of the list without finding a top-level
+     * message, that means the thread is a cycle (or set of cycles)
+     * and any message can be considered top-level.  Choose the oldest
+     * message, which happens to be first in our list.
+     */
+    if (first_node) {
+       message = first_node->message;
+       in_reply_to = _notmuch_message_get_in_reply_to (message);
+       if (thread->toplevel_list->head &&
+           in_reply_to && strlen (in_reply_to) &&
            g_hash_table_lookup_extended (thread->message_hash,
                                          in_reply_to, NULL,
                                          (void **) &parent))

diff --git a/test/T050-new.sh b/test/T050-new.sh
index 320a76460c213a8a675f1888c61520b4a1ca02ec..9025fa7aa63e3ac75774f0663d8cd1c63b7f45e4 100755 (executable)
--- a/test/T050-new.sh
+++ b/test/T050-new.sh
@@ -359,7 +359,6 @@ test_begin_subtest "reference loop does not crash"
 test_expect_code 0 "notmuch show --format=json id:mid-loop-12@example.org id:mid-loop-21@example.org > OUTPUT"
 
 test_begin_subtest "reference loop ordered by date"
-test_subtest_known_broken
 threadid=$(notmuch search --output=threads  id:mid-loop-12@example.org)
 notmuch show --format=mbox $threadid | grep '^Date'  > OUTPUT
 cat <<EOF > EXPECTED