Error when deploying 1.8.7 app: "NoMethodError: undefined method `select!' for ["zlib@openssh.com", "zlib"]:Array"

On recent/fresh installations of Ruby 1.8.7 you may encounter this error why calling any bundled binary (or just bundle exec):

/home/arne/.rvm/gems/ruby-1.8.7-p374@global/gems/rubygems-bundler-1.4.2/lib/rubygems-bundler/noexec.rb:75:in ...

Let's say we have posts with an attribute title that is mandatory.

Our example feature request is to tag these posts with a limited number of tags. The following chapters explain different approaches in Rails, how you can assign such a...

The problem

When using the asset pipeline your assets (images, javascripts, stylesheets, fonts) live in folders inside app:

app/assets/fonts
app/assets/images
app/assets/javascripts
app/assets/stylesheets

Wit...

So you're getting an error like this:

undefined method `activate_bin_path' for Gem:Module (NoMethodError)

Here is what happened:

• You installed a recent version of Rubygems
• You installed some gems that install a binary (like `bun...

When HTTP clients make an request they can define which response formats they can process. They do it by adding a header to the HTTP request like this:

Accept: application/json

This means the client will only understand JSON respon...

When deploying with capistrano it's possible you get this "error" message:

*** [err :: example.com] There are no Phusion Passenger-served applications running whose paths begin with '/var/www/example.com'.
*** [err :: example.com] 

This ...

I believe that when WEBrick has trouble bringing up your Rails application, the WEBrick component that is supposed to print you a pretty error message has a bug and sometimes fails with this message:

"undefined method `bytesize' for #<Array>"...

Usually you add errors to :base in ActiveRecord, in case no appropriate attribute could be used to add the error.

Simple Form...

I got this error when running Rails 2.3 tests for Rails LTS. More stacktrace:

NoMethodError: undefined method `cache' for Gem:Module
    /vagrant/rails-2-3-lts-repository/railties/lib/rails_generator/lookup.rb:212:in `e...

You are probably using Ruby 1.8.7 with a too recent versions of Rubygems.

Downgrade your Rubygems to the latest version that works with 1.8.7.

See also

• [Fix Rubygems warning: Gem.source_index is deprecated, use Specifica...