Presently, the code which finds the parent of a message as it is being added to the database assumes that the first Message-ID-like substring of the In-Reply-To header is the parent Message ID. Some mail clients, however, put stuff other than the Message-ID of the parent in the In-Reply-To header, such as the email address of the sender of the parent. This can fool notmuch.
The updated algorithm prefers the last Message ID in the References header. The References header lists messages oldest-first, so the last Message ID is the parent (RFC2822, p. 24). The References header is also less likely to be in a non-standard syntax (http://cr.yp.to/immhf/thread.html, http://www.jwz.org/doc/threading.html). In case the References header is not to be found, fall back to the old behavior. V2 of this patch, incorporating feedback from Jani and (indirectly) Austin. --- lib/database.cc | 48 +++++++++++++++++++++++++++++++++--------------- test/thread-replies | 4 ---- 2 files changed, 33 insertions(+), 19 deletions(-) diff --git a/lib/database.cc b/lib/database.cc index 91d4329..52ed618 100644 --- a/lib/database.cc +++ b/lib/database.cc @@ -501,8 +501,10 @@ _parse_message_id (void *ctx, const char *message_id, const char **next) * 'message_id' in the result (to avoid mass confusion when a single * message references itself cyclically---and yes, mail messages are * not infrequent in the wild that do this---don't ask me why). -*/ -static void + * + * Return the last reference parsed, if it is not equal to message_id. + */ +static char * parse_references (void *ctx, const char *message_id, GHashTable *hash, @@ -511,7 +513,7 @@ parse_references (void *ctx, char *ref; if (refs == NULL || *refs == '\0') - return; + return NULL; while (*refs) { ref = _parse_message_id (ctx, refs, &refs); @@ -519,6 +521,17 @@ parse_references (void *ctx, if (ref && strcmp (ref, message_id)) g_hash_table_insert (hash, ref, NULL); } + + /* The return value of this function is used to add a parent + * reference to the database. We should avoid making a message + * its own parent, thus the following check. + */ + + if (ref && strcmp(ref, message_id)) { + return ref; + } else { + return NULL; + } } notmuch_status_t @@ -1510,28 +1523,33 @@ _notmuch_database_link_message_to_parents (notmuch_database_t *notmuch, { GHashTable *parents = NULL; const char *refs, *in_reply_to, *in_reply_to_message_id; + const char *last_ref_message_id, *this_message_id; GList *l, *keys = NULL; notmuch_status_t ret = NOTMUCH_STATUS_SUCCESS; parents = g_hash_table_new_full (g_str_hash, g_str_equal, _my_talloc_free_for_g_hash, NULL); + this_message_id = notmuch_message_get_message_id (message); refs = notmuch_message_file_get_header (message_file, "references"); - parse_references (message, notmuch_message_get_message_id (message), - parents, refs); + last_ref_message_id = parse_references (message, + this_message_id, + parents, refs); in_reply_to = notmuch_message_file_get_header (message_file, "in-reply-to"); - parse_references (message, notmuch_message_get_message_id (message), - parents, in_reply_to); - - /* Carefully avoid adding any self-referential in-reply-to term. */ - in_reply_to_message_id = _parse_message_id (message, in_reply_to, NULL); - if (in_reply_to_message_id && - strcmp (in_reply_to_message_id, - notmuch_message_get_message_id (message))) - { + in_reply_to_message_id = parse_references (message, + this_message_id, + parents, in_reply_to); + + /* For the parent of this message, use the last message ID of the + * References header, if available. If not, fall back to the + * first message ID in the In-Reply-To header. */ + if (last_ref_message_id) { + _notmuch_message_add_term (message, "replyto", + last_ref_message_id); + } else if (in_reply_to_message_id) { _notmuch_message_add_term (message, "replyto", - _parse_message_id (message, in_reply_to, NULL)); + in_reply_to_message_id); } keys = g_hash_table_get_keys (parents); diff --git a/test/thread-replies b/test/thread-replies index a902691..28c2b1f 100755 --- a/test/thread-replies +++ b/test/thread-replies @@ -11,7 +11,6 @@ constructed properly, even in the presence of non-RFC-compliant headers' . ./test-lib.sh test_begin_subtest "Use References when In-Reply-To is broken" -test_subtest_known_broken add_message '[id]="f...@one.com"' \ '[subject]=one' add_message '[in-reply-to]="mumble"' \ @@ -46,7 +45,6 @@ expected=`echo "$expected" | notmuch_json_show_sanitize` test_expect_equal_json "$output" "$expected" test_begin_subtest "Prefer References to In-Reply-To" -test_subtest_known_broken add_message '[id]="f...@two.com"' \ '[subject]=two' add_message '[in-reply-to]="<b...@baz.com>"' \ @@ -77,7 +75,6 @@ expected=`echo "$expected" | notmuch_json_show_sanitize` test_expect_equal_json "$output" "$expected" test_begin_subtest "Use In-Reply-To when no References" -test_subtest_known_broken add_message '[id]="f...@three.com"' \ '[subject]="three"' add_message '[in-reply-to]="<f...@three.com>"' \ @@ -104,7 +101,6 @@ expected=`echo "$expected" | notmuch_json_show_sanitize` test_expect_equal_json "$output" "$expected" test_begin_subtest "Use last Reference" -test_subtest_known_broken add_message '[id]="f...@four.com"' \ '[subject]="four"' add_message '[id]="b...@four.com"' \ -- 1.8.1.5 _______________________________________________ notmuch mailing list notmuch@notmuchmail.org http://notmuchmail.org/mailman/listinfo/notmuch