Account::ProviderMethods#grouped_by_target contains iterators nested 2 deep Open
hash[target] = select{ |fd| fd.target.downcase == target }
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A Nested Iterator
occurs when a block contains another block.
Example
Given
class Duck
class << self
def duck_names
%i!tick trick track!.each do |surname|
%i!duck!.each do |last_name|
puts "full name is #{surname} #{last_name}"
end
end
end
end
end
Reek would report the following warning:
test.rb -- 1 warning:
[5]:Duck#duck_names contains iterators nested 2 deep (NestedIterators)
Account::ProviderMethods#create_first_cinstance refers to 'application_plans' more than self (maybe move it to another class?) Open
plan = application_plans.default || application_plans.first!
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Feature Envy occurs when a code fragment references another object more often than it references itself, or when several clients do the same series of manipulations on a particular type of object.
Feature Envy reduces the code's ability to communicate intent: code that "belongs" on one class but which is located in another can be hard to find, and may upset the "System of Names" in the host class.
Feature Envy also affects the design's flexibility: A code fragment that is in the wrong class creates couplings that may not be natural within the application's domain, and creates a loss of cohesion in the unwilling host class.
Feature Envy often arises because it must manipulate other objects (usually its arguments) to get them into a useful form, and one force preventing them (the arguments) doing this themselves is that the common knowledge lives outside the arguments, or the arguments are of too basic a type to justify extending that type. Therefore there must be something which 'knows' about the contents or purposes of the arguments. That thing would have to be more than just a basic type, because the basic types are either containers which don't know about their contents, or they are single objects which can't capture their relationship with their fellows of the same type. So, this thing with the extra knowledge should be reified into a class, and the utility method will most likely belong there.
Example
Running Reek on:
class Warehouse
def sale_price(item)
(item.price - item.rebate) * @vat
end
end
would report:
Warehouse#total_price refers to item more than self (FeatureEnvy)
since this:
(item.price - item.rebate)
belongs to the Item class, not the Warehouse.
Method find_or_default
has a Cognitive Complexity of 6 (exceeds 5 allowed). Consider refactoring. Open
def find_or_default(id = nil)
owner = proxy_association.owner
raise ProviderOnlyMethodCalledError if owner.buyer?
# TODO
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Cognitive Complexity
Cognitive Complexity is a measure of how difficult a unit of code is to intuitively understand. Unlike Cyclomatic Complexity, which determines how difficult your code will be to test, Cognitive Complexity tells you how difficult your code will be to read and comprehend.
A method's cognitive complexity is based on a few simple rules:
- Code is not considered more complex when it uses shorthand that the language provides for collapsing multiple statements into one
- Code is considered more complex for each "break in the linear flow of the code"
- Code is considered more complex when "flow breaking structures are nested"
Further reading
Account::ProviderMethods#signup is a writable attribute Open
attr_writer :signup
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A class that publishes a setter for an instance variable invites client classes to become too intimate with its inner workings, and in particular with its representation of state.
The same holds to a lesser extent for getters, but Reek doesn't flag those.
Example
Given:
class Klass
attr_accessor :dummy
end
Reek would emit the following warning:
reek test.rb
test.rb -- 1 warning:
[2]:Klass declares the writable attribute dummy (Attribute)
Account::ProviderMethods#is_billing_buyers? performs a nil-check Open
!billing_strategy.nil?
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A NilCheck
is a type check. Failures of NilCheck
violate the "tell, don't ask" principle.
Additionally, type checks often mask bigger problems in your source code like not using OOP and / or polymorphism when you should.
Example
Given
class Klass
def nil_checker(argument)
if argument.nil?
puts "argument isn't nil!"
end
end
end
Reek would emit the following warning:
test.rb -- 1 warning:
[3]:Klass#nil_checker performs a nil-check. (NilCheck)
Account::ProviderMethods has the variable name 'z' Open
ALLOWED_TIMEZONES = ActiveSupport::TimeZone.all.reject { |z| z.utc_offset % 3600 != 0 }.freeze
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An Uncommunicative Variable Name
is a variable name that doesn't communicate its intent well enough.
Poor names make it hard for the reader to build a mental picture of what's going on in the code. They can also be mis-interpreted; and they hurt the flow of reading, because the reader must slow down to interpret the names.