handle message "updates" by merging labels and overwriting other fields

Later versions of the same message typically happen because the original
was sent to a mailing list. This change merges in labels from later messages
and allows them to overwrite the other message fields (which was the
original behavior which this branch has broken).

This means that messages sent to mailing lists and then received back from
them preserve subject line rewriting and any auto-label application.

diff --git a/lib/sup/index.rb b/lib/sup/index.rb
index 38d4e1f0672bef9409d60e9e952f37f9703067b2..85f527003c44a66cb799efc8337f0f0ed98c3209 100644 (file)
--- a/lib/sup/index.rb
+++ b/lib/sup/index.rb
@@ -185,19 +185,34 @@ EOS
     ## index, reuse it (which avoids having to reload the entry from the source,
     ## which can be quite expensive for e.g. large threads of IMAP actions.)
     ##
+    ## exception: if the index entry belongs to an earlier version of the
+    ## message, use everything from the new message instead, but union the
+    ## flags. this allows messages sent to mailing lists to have their header
+    ## updated and to have flags set properly.
+    ##
     ## written in this manner to support previous versions of the index which
     ## did not keep around the entry body. upgrading is thus seamless.
-
     entry ||= {}
-    d =
-    {
+    labels = m.labels.uniq # override because this is the new state, unless...
+
+    ## if we are a later version of a message, ignore what's in the index,
+    ## but merge in the labels.
+    if entry[:source_id] && entry[:source_info] && entry[:label] &&
+      ((entry[:source_id] != source_id) || (entry[:source_info] < source_info))
+      labels = (entry[:label].split(/\s+/).map { |l| l.intern } + m.labels).uniq
+      Redwood::log "found updated version of message #{m.id}: #{m.subj}"
+      Redwood::log "merged labels are #{labels.inspect} (index #{entry[:label].inspect}, message #{m.labels.inspect})"
+      entry = {}
+    end
+
+    d = {
       :message_id => (entry[:message_id] || m.id),
       :source_id => (entry[:source_id] || source_id),
       :source_info => (entry[:source_info] || m.source_info),
       :date => (entry[:date] || m.date.to_indexable_s),
       :body => (entry[:body] || m.indexable_content),
       :snippet => snippet, # always override
-      :label => m.labels.uniq.join(" "), # always override
+      :label => labels.uniq.join(" "),
       :from => (entry[:from] || (m.from ? m.from.indexable_content : "")),
       :to => (entry[:to] || (m.to + m.cc + m.bcc).map { |x| x.indexable_content }.join(" ")),
       :subject => (entry[:subject] || wrap_subj(m.subj)),