I've been meaning to update this blog to Octopress 2.1 for some time now (mainly to use its linklog feature), but I kept procrastinating because I was intimidated by the prospect of diving back into Git and Rake commands to do so. When I finally decided to get my hands dirty the other day, I ran into problems—as I had feared—and ended up spending a few hours debugging. I'm writing this blog post to document the process.
I'd like to emphasize that I am entirely aware that I am using beta software (caveat emptor) and that, consequently, I do not intend for this to reflect negatively on Octopress in any way. I love Octopress because it allows me to write a nice, professional-looking blog using nothing but simple, elegant Markdown. In fact, I want to document my experience with the 2.1 branch to make it easier for other people to use it, too.
Okay, are you with me now? Let's get started.
Rake Tasks Have Changed
After upgrading to the 2.1 branch of Octopress, I tried running rake update_source and rake update_style (according to the instructions given by the documentation for the 2.1 branch) and was somewhat surprised to find that these tasks don't work any more. Curious, I used rake -T to get a list of all the available rake tasks. As it turns out, there are a lot of them.
Octopress 2.1 Rake Tasks
rake clean # Clean out caches: .pygments-cache, .gist-cache, .sass-cache, and Compass-generated files.
rake install_stylesheets[theme]# Install stylesheets for a theme
rake update_stylesheets[theme]# Move stylesheets to stylesheets.old, install stylesheets theme updates, replace stylesheets/custom with stylesheets.old/custom
rake update_template[theme]# Move source to source.old, install source theme updates, replace source/_includes/navigation.html with source.old's navigation
The following tasks have been removed:
Deprecated Octopress 2.0 Rake Tasks
rake list # list tasks
rake update_source[theme]# Move source to source.old, install source theme updates, replace source/_includes/navigation.html with source.old's navigation
rake update_style[theme]# Move sass to sass.old, install sass theme updates, replace sass/custom with sass.old/custom
Updates Are Broken
Unfortunately, I encountered the following error when I ran rake update.
Error Updating Octopress
Removed existing .old directory
rm -r .old
cp -r /. .old
cannot handle socket
/path/to/octopress/Rakefile:309:in `block in <top (required)>'
/path/to/octopress/Rakefile:264:in `block in <top (required)>'
I have no idea what was causing this error and I certainly don't know enough about Octopress's internals to make much of an educated guess. Thankfully, I don't necessarily have to: all I really need to do is isolate the commit that caused this problem. I can use the entire 2.1 branch up to that point.
How do I find the offending commit?
Git Bisect to the Rescue
I remembered that this sort of situation is exactly what git bisect is for. Do a binary search through the commit tree, starting with the latest bad commit and ending with the last known good commit. I had created my 2.1 branch off of master, which I knew to be good, so I starting git bisect with the following commands.
Start git bisect
$ git bisect start
$ git bisect bad
$ git bisect good master
This produced the following output.
Step 1 of git bisect
Bisecting: 175 revisions left to test after this (roughly 8 steps)
[be443098d683a38893c7458ca00f5d14a5de144a] Merge pull request #878 from Eric-Guo/eric_fix
Because I wanted to test Octopress's update process, I needed to make absolutely sure that I had generated the Octopress theme (source directories) correctly. I also wanted to make sure that all of my bundles were up to date. To accomplish this, I used the following (probably horribly inefficient) procedure.
“Uninstall” the default Octopress theme by removing the source and (if they exist) sass directories.
rm -r sass sass.old source source.old
Re-install the default Octopress theme.
Try to update Octopress.
Discard all changes to Gemfile.lock.
git checkout -- Gemfile.lock
Run git bisect good if step 4 was successful or git bisect bad if it failed. Repeat steps 1–6 until there are no more commits to check.
Clean up the source directories (rm -r source source.old) and then run git bisect reset to stop bisecting and restore HEAD to its original location.
When step 4 succeeded, it produced output similar to the following.
And finally, here is the result of my little excursion:
Results from git bisect
7bdab0e65c86d8bd9fe3b46a4bf1ca92b1e1a54e is the first bad commit
Author: Brandon Mathis <email@example.com>
Date: Sun Feb 10 02:47:53 2013 -0600
- Added Guard for file watching
- Configs can be automatically reloaded
- Static asset changes do not trigger Jekyll build
- CommonJS modular js support proved by stich-rb
- Environment variables toggle uglify and fingerprinting
- New Jekyll plugin config_tag
- Added theme specific configurations
- Custome Jekyll Guard to the rescue
- Install, Generate, Watch, and Preview work with Guard now.
- Now configs are no longer tracked by Octopress, only theme defauts are.
- Console messages can be colorized.
- misc config reorganization and improvements
:040000 040000 3d2ca5d42be900e081050cd31344780ffbbb0b20 bef0756debd5ac71f40b5696a8ed87af77f8268f M .themes
:100644 100644 ed67ec9d37a79e98ed0d3b10daf7bf88ef54ffc1 a4c8628d5388e60783d64800842e794074b773e9 M Gemfile
:100644 100644 366bcc9b9f50a94de8b652f9a1721d63dce7a083 9a7816d5e36027850df9f268bdf0b103574c4057 M Gemfile.lock
:000000 100644 0000000000000000000000000000000000000000 50e4dd9007a6ed9223312f43951ceb9c8e264b76 A Guardfile
:100644 100644 ead162a40086ec9afa4d903ade378545b8bcd695 1bac57ede8226f1331867bc6b9bdf1b3c15ab03a M Rakefile
:040000 000000 5bc14cccc0e1433f673dbf7348d417030d17b94b 0000000000000000000000000000000000000000 D _config
:100644 100644 72cbc0a04e91820163faae78df5caa03fc39d347 8850a0498347f8b4deaae0422a4dc4fe4f28607b M config.rb
:040000 040000 4b22768afd286d8e359075dbcc5fba632ea9564b c9f7e99034f425bf3de51cabec1bb7925bfbcbfb M lib
:040000 040000 2d7995a9500dffd5ef9421a67b1a16f3794f0f8b 91ce26b900afd8916d30a9471b5e09892813fde3 M plugins
I don't know precisely what happened in this commit to break the update process, but it is suspect because it adds several features and changes several files all at once.
Branch Off the Last Known Good Commit
Once I found the offending commit (7bdab0e65), I was able to create a new branch off of its parent (4972fb6c62) and continue blogging. I noticed that some settings have been moved, but that's a topic for another post.