This was originally about automatic updates over SSH2 not working for me when I upgraded to WordPress 2.8. WordPress 2.9 is out now, and this problem turned out not to be their fault.
After filing a bug report and working through it with the WordPress team, a solution was eventually found (see the final update to this post). If you’re not inclined to skip to the end then here’s your TL:DR: turn off open_basedir or make the declaration less restrictive.
If you’re not experiencing this problem (and Google says you’re landing here if you’re looking for help setting up SFTP/SSH updating for WordPress), I don’t think this write-up will be of much help. After upgrading to WordPress 2.8 I discovered that this update has broken automatic core and plugin updates for me. I use SSH2/SFTP as I don’t trust, like, need, or support FTP, and the SSH log only shows that the PECL module is opening a connection and then closing it, with WordPress returning only the following to to the browser window.
Unable to locate WordPress Content directory (wp-content).
I dug through how WordPress handles upgrades, and tracked this all down to the /wp-admin/includes/class-wp-filesystem-ssh2.php file.
UPDATE 6/13/2009 @4:40 p.m. EST
From what I found, the rewrite of the SSH/SFTP2 update function happened because the ssh2.sftp wrapper was introduced. This replaced the older version of the function which copied contents into temp files and pushed the data around. It was a drastic speed increase, but it doesn’t bloody work on my system for one reason or another.
UPDATE 6/13/2009 @7:16 p.m. EST
I’ve officially cried “uncle!” and turned to the most wretched hive of scum and villainy in blogging, the WordPress forums (as well as their bug reporting and ticketing system). I also identified the patch which introduced the code which caused SSH2 support to go flying off the rails for me.
UPDATE 6/18/2009 @4:17 p.m. EST
The WordPress team has marked this bug as belonging to milestone 2.9. There is a slim chance that maybe I’ll see some relief in 2.8.1, but more than likely they’re going to yet again refactor how SSH2 works for automatic upgrades. If this changes, I will update this post accordingly. For now, I believe I may have to simply let it be broken.
UPDATE 12/19/2009 @10:30 p.m. EST
Months later, I worked out what the problem was. Ultimately a conflict caused by use of PHP’s open_basedir and safe_mode kept the SSH2 module from accessing resources it needed. The way the ssh2.sftp wrapper works would bump into overly restrictive basedir declarations. If you are experiencing this problem and you check your error logs after turning them up to “debug", you’ll probably find out what directory or file is causing this conflict. It’s ultimately moot, since things like safe_mode are deprecated in PHP 5.3 and being outright removed in PHP 6.
Oddly enough, updating libssh2 to something more up-to-date than the outdated RPM provided by Dag for RedHat Enterprise Linux/CentOS made a HUGE speed difference. Definitely something to look into if SSH updating is slow for you.
Other than that, this round of upgrades has been mostly painless, and the hyped speed increases are not just hyperbole. WordPress 2.8 feels only slight under-baked beyond SSH2 hiccups. I confess that I haven’t had a chance to play with the redesigned sidebar widget administration yet though, as I haven’t even figured out how I want to implement support for sidebar widgets into this theme.
The bug that deletes some custom fields if you update posts that have them is still there. No idea how to begin tracking that one down, but I can state authoritatively that it’s theme and plugin independent. Why am I linking to some dudes blog, and not the official WordPress bug tracker? because I don’t even know where WordPress keeps its bug tracker.
I also had to reset WordPress Blog stats because WordPress was tracking the wrong subdomain for all of my stats. The numbers tallied up with Google Analytics and the AWFFull log grinder, but the URLs were all effed up. I fixed the problem on the WordPress.com backend, and in the process lost months of aggregated history.
The upshot to this loss is that I hope to have a new round of search hit inspired commentary ready to go in a week or two.