I wanted to upgrade my WordPress installation (1.5) to the current version (220.127.116.11). While fiddling around with it and MarsEdit, I discovered that Trackback with XML-RPC doesn't seem to work at all, at least not the way MarsEdit sends Trackback URIs. MarsEdit sends Trackbacks as an array of data (
<value><array><data><value><string>http://www.myuri.com...[closing tags]). That's not what the XML-RPC API of WordPress seems to expect or is able to handle. It seems to expect a comma-separated list of URIs. With that behaviour, Trackback URIs would only show up in the admin view as "Array". I hacked a few of the involved scripts to work correctly in that manner, i.e. implode the Trackback URI list in case it's an array.
The second bug was a lost post id when editing an existing entry. In xml-rpc.php, in method mw_editPost, somewhere between fetching the post_ID (line 563) and sending the trackbacks (which I tested specifically) and the call to trackback_url_list() the post_ID is set to 1 as it seems. Since wp_update_post() returns the number of affected rows of its update, it might be obivous, where that 1 comes from.
So I wonder, if I'm the only one experiencing those problems, and if it's of any help, I'll open an issue for that and attach my patches.