short circuiting and side effects

example.rb

# as suggested by @mcmire, https://twitter.com/mcmire/status/96632723220869120
# and clarified in https://twitter.com/mcmire/status/96647536521129985

class Array
  def thoroughly_all?(&block)
    all_true = true
    each {|obj| all_true &= yield(obj) }
    all_true
  end
end

if models.thoroughly_all? { |m| m.valid? }
  # ... do stuff
end

# I argue that this is not a good idea, because:
#
# 1. It extends core classes unnecessarily, which can be ok, but:
# 2. It relies on implicit (and potentially unclear) side effects.

# Without looking through the codebase to find out what "thoroughly_all?" is,
# it's not immediately obvious what's going on.
#
# In my opinion, it's much better to be explicit, even if it's a bit more code:

# validate everything explicitly
models.map { |m| m.valid? }

# then act on the results
if models.all? { |m| m.errors.empty? }
  # ...
end