Code Fix » 2007 » February

I’m starting to see a theme here

Jordan — Wed, 28 Feb 2007 00:20:44 +0000

I hit this one after installing the Simpla theme, but you could hit this with any theme.

Symptoms (after switching to a new WordPress theme):

The screenshot for the theme doesnt show up in the theme selector
The pages on the blog are unstyled
Theme images don’t load correctly
Trying to manually open the URL’s for the stylesheets, images, etc, gives you a 404 page

The problem was that permissions were not set correctly on the unzipped theme folder. I had to make sure there was read and execute access granted on the folder and all the theme files (chmod 755 for you command-line junkies). You could probably do this through your FTP client, if it’s a decent one (I recommend Smart FTP).

Cache me if you can

Jordan — Tue, 27 Feb 2007 22:44:39 +0000

It’s ironic that the second post on this blog is about fixing the software the blog is running on. Oh well, such is software. When I first set up this site, I wanted to make it as performance-friendly as possible, so I set up the WordPress WP-Cache plugin. Everything seemed to work fine. However, I wasn’t quite finished messing with some other plugins, and I ran into issues with cached versions of pages not reflecting tweaks I was making in some of the core files.

Not a problem, says I…

I’ll just deactivate the WP-Cache plugin until I’m finished developing. As it turns out, that doesn’t work. Once you activate (on the plugins page) and enable (on the WP-Cache settings page) the WP-Cache plugin, to turn it off, you have to disable it (on the WP-Cache settings page). Deactivating the plugin does not disable caching.

Here we go

Jordan — Tue, 27 Feb 2007 03:33:40 +0000

Enough time has been spent fixing bugs and getting basic things working. Hopefully, this site will help fix that.

I mostly work with Java and Eclipse, but do enough web stuff to beat my head against a wall every once in a while. This site will have tips, tutorials, bug workarounds, and anything else I can think of that people might find worthwhile.

I suppose I could start with the simplest and most embarrassing debugging problem I ever hit…

In Eclipse (and most interactive debuggers), you can set up expressions that are evaluated whenever the debugged process halts. Because these expressions are evaluated in the current thread context, they have full access to read (or write to) local variables. I happened to put a typo in one of these expressions, and did the ol’ “assign instead of compare” trick, evaluating “str = null” instead of “str == null”.

I didn’t really notice the bug, and didn’t end up needing to see whether str was null or not, so I went back to another view, hiding the debug expressions I had set (out of sight, out of mind, right?). It was about that time I started noticing a bizarre new bug… whenever I would hit a breakpoint, str would be null, even if the code I was stepping through didn’t do a thing with str! Fancy that!

Lesson 1: If there is weird behavior when debugging, check to see if expressions are being evaluated without you knowing.

Lesson 2: Use “null == str” instead of “str == null” to avoid assignment vs. compare bugs. (this actually doesn’t work in all languages… wait for a future post)