Upgrading from 2.x to 3.x

Upgrading from an older version of Jekyll? A few things have changed in Jekyll 3 that you’ll want to know about.

Before we dive in, go ahead and fetch the latest version of Jekyll:

gem update jekyll
Since v3.2 Jekyll requires Ruby version >= 2.1
Diving in

Want to get a new Jekyll site up and running quickly? Simply run jekyll new SITENAME to create a new folder with a bare bones Jekyll site.

site.collections has changed

In 2.x, your iterations over site.collections yielded an array with the collection label and the collection object as the first and second items, respectively. In 3.x, this complication has been removed and iterations now yield simply the collection object. A simple conversion must be made in your templates:

  • collection[0] becomes collection.label
  • collection[1] becomes collection

When iterating over site.collections, ensure the above conversions are made.

For site.collections.myCollection in Jekyll 2, you now do:

{% assign myCollection = site.collections | where: "label", "myCollection" | first %}

This is a bit cumbersome at first, but is easier than a big for loop.

Dropped dependencies

We dropped a number of dependencies the Core Team felt were optional. As such, in 3.0, they must be explicitly installed and included if you use any of the features. They are:

  • jekyll-paginate – Jekyll’s pagination solution from days past
  • jekyll-coffeescript – processing of CoffeeScript
  • jekyll-gist – the gist Liquid tag
  • pygments.rb – the Pygments highlighter
  • redcarpet – the Markdown processor
  • toml – an alternative to YAML for configuration files
  • classifier-reborn – for site.related_posts

Future posts

A seeming feature regression in 2.x, the --future flag was automatically enabled. The future flag allows post authors to give the post a date in the future and to have it excluded from the build until the system time is equal or after the post time. In Jekyll 3, this has been corrected. Now, --future is disabled by default. This means you will need to include --future if you want your future-dated posts to generate when running jekyll build or jekyll serve.

Future Posts on GitHub Pages

An exception to the above rule are GitHub Pages sites, where the --future flag remains enabled by default to maintain historical consistency for those sites.

Layout metadata

Introducing: layout. In Jekyll 2 and below, any metadata in the layout was merged onto the page variable in Liquid. This caused a lot of confusion in the way the data was merged and some unexpected behaviour. In Jekyll 3, all layout data is accessible via layout in Liquid. For example, if your layout has class: my-layout in its YAML front matter, then the layout can access that via {{ layout.class }}.

Syntax highlighter changed

For the first time, the default syntax highlighter has changed for the highlight tag and for backtick code blocks. Instead of Pygments.rb, it’s now Rouge. If you were using the highlight tag with certain options, such as hl_lines, they may not be available when using Rouge. To go back to using Pygments, set highlighter: pygments in your _config.yml file and run gem install pygments.rb or add gem 'pygments.rb' to your project’s Gemfile.

In Jekyll 3 and above, relative permalinks have been deprecated. If you created your site using Jekyll 2 and below, you may receive the following error when trying to serve or build:

Since v3.0, permalinks for pages in subfolders must be relative to the site
source directory, not the parent directory. Check
https://jekyllrb.com/docs/upgrading/ for more info.

This can be fixed by removing the following line from your _config.yml file:

relative_permalinks: true

In Jekyll 2, any URL constructed from the permalink: field had a trailing slash (/) added to it automatically. Jekyll 3 no longer adds a trailing slash automatically to permalink: URLs. This can potentially result in old links to pages returning a 404 error. For example, suppose a page previously contained the YAML permalink: /:year-:month-:day-:title that resulted in the URL example.com/2016-02-01-test/ (notice the trailing slash), Jekyll internally generates a folder named 2016-02-01-test. In Jekyll 3, the same permalink: generate the file 2016-02-01-test.html and the URL for the same page will be example.com/2016-02-01-test, and consequently any links to the old URL will result in a 404 error. In order to maintain the same URLs and avoid this problem, a trailing slash should be added to the permalink: field, for example permalink: /:year-:month-:day-:title/.

All my posts are gone! Where’d they go!

Try adding future: true to your _config.yml file. Are they showing up now? If they are, then you were ensnared by an issue with the way Ruby parses times. Each of your posts is being read in a different timezone than you might expect and, when compared to the computer’s current time, is “in the future.” The fix for this is to add a timezone offset to each post (and make sure you remove future: true from your _config.yml file). If you’re writing from California, for example, you would change this:

date: 2016-02-06 19:32:10

to this (note the offset):

date: 2016-02-06 19:32:10 -0800

My categories have stopped working!

If you organized your categories as /_posts/code/2008-12-24-closures.md, you will need to restructure your directories to put the categories above the _posts directories, as follows: /code/_posts/2008-12-24-closures.md.

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Licensed under the MIT license.