How to solve the “undefined method `deep_symbolize_keys’ for nil:NilClass” error in Rails

I was trying to migrate a table in my Rails app and got this error: undefined method `deep_symbolize_keys’ for nil:NilClass It’s a strange error, and there weren’t very many hits on Google. A lighthouse ticket provided a clue. The problem wasn’t one of my plugins or gems — it was i18n itself. Upgrading from 0.4.1 …

Fixing the mysterious “Element script is missing required attribute src” error

Suppose you're using the W3C validator to validate HTML5. Here's a sample document: <!doctype html> <html lang="en" xml:lang="en"> <head> <meta charset="utf-8" /> <title>Hello</title> <script type="text/javascript" charset="utf-8"> //<![CDATA[ var foo = 1; //]]> </script> </head> <body> </body> </html> Everything looks right, but you get this mysterious error: Line 6, Column 48: Element script is missing required …