undefined method `delete!' for nil:NilClass

[pkra]

Moving this over from github/pages-gem#441.

After updating gh-pages from 134 to 136, I get build errors

  Liquid Exception: undefined method `delete!' for nil:NilClass in /_layouts/default.html

Disabling the SEO plugin resolved this (and was the only relevant update in 136 I could see).

• Link to the source repo: https://github.com/mathjax/mathjax-website
• Link to travis build with same failure (which is used for testing, we let github build the page): https://travis-ci.org/mathjax/MathJax-website/builds/227852201

Any pointers would be welcome.

[mmistakes]

I was bit by the same thing. If you add --verbose and --trace to jekyll build it'll help identify what post/page jekyll-seo-tag is breaking on.

In my case I had posts that had unused stuff like author: false in their YAML Front Matter. Removing those lines fixed my builds.

@pkra The culprits in your repo seem to be the author object. Like in this post

author:
  login: robertm
  email: stevenp@dessci.com
  display_name: Robert Miner
  first_name: Robert
  last_name: Miner

I'm guessing this is all related to the converting the author stuff since into a drop: C:/Ruby22-x64/lib/ruby/gems/2.2.0/gems/jekyll-seo-tag-2.2.2/lib/jekyll-seo-tag/drop.rb:91:in author': undefined method delete!' for nil:NilClass (NoMethodErro r)

[pkra]

Thanks for debugging this for me @mmistakes! And sorry for not looking into how to get better error information from jekyll 🙇‍♂️.

I should've guessed it's related to the last bug we ran into -- I missed a few posts, apparently.

Leaving it to the maintainers to decide if this is a bug or expected behavior.

[benbalter]

Fixed via #203. The problem arises when the post has an author hash that contains neither a name nor twitter key. The plugin is attempting to normalize the non-existent Twitter handle by stripping the @.

[pkra]

Thanks for the quick response & fix, @benbalter.

[mbrav]

Hi, I'm having a similar problem.

Liquid Exception: undefined method `+' for nil:NilClass in /_layouts/default.html
bundler: failed to load command: jekyll (/usr/local/bin/jekyll)
NoMethodError: undefined method `+' for nil:NilClass

Any suggestions? Here is the beginning of the --trace.

  /usr/local/lib/ruby/gems/2.4.0/gems/jekyll-seo-tag-2.2.2/lib/jekyll-seo-tag/drop.rb:43:in `title'
  /usr/local/lib/ruby/gems/2.4.0/gems/jekyll-seo-tag-2.2.2/lib/jekyll-seo-tag/drop.rb:25:in `title?'
  /usr/local/lib/ruby/gems/2.4.0/gems/jekyll-3.4.3/lib/jekyll/drops/drop.rb:52:in `public_send'
  /usr/local/lib/ruby/gems/2.4.0/gems/jekyll-3.4.3/lib/jekyll/drops/drop.rb:52:in `[]'