Cinch::Plugins::Bacon#command_bacon_gift refers to 'm' more than self (maybe move it to another class?) Open
m.action_reply "gives #{to_user} a strip of delicious bacon as a gift from #{m.user}."
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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.
Cinch::Plugins::Bacon has no descriptive comment Open
class Bacon
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Classes and modules are the units of reuse and release. It is therefore considered good practice to annotate every class and module with a brief comment outlining its responsibilities.
Example
Given
class Dummy
# Do things...
end
Reek would emit the following warning:
test.rb -- 1 warning:
[1]:Dummy has no descriptive comment (IrresponsibleModule)
Fixing this is simple - just an explaining comment:
# The Dummy class is responsible for ...
class Dummy
# Do things...
end
Cinch::Plugins::Bacon#with_channel_user performs a nil-check Open
return if target_user.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)
Cinch::Plugins::Bacon#with_channel_user doesn't depend on instance state (maybe move it to another class?) Open
def with_channel_user(m, user)
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A Utility Function is any instance method that has no dependency on the state of the instance.
Cinch::Plugins::Bacon#command_bacon doesn't depend on instance state (maybe move it to another class?) Open
def command_bacon(m)
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A Utility Function is any instance method that has no dependency on the state of the instance.
Cinch::Plugins::Bacon#command_bacon has the parameter name 'm' Open
def command_bacon(m)
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An Uncommunicative Parameter Name
is a parameter 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.
Cinch::Plugins::Bacon#command_bacon_gift has the parameter name 'm' Open
def command_bacon_gift(m, user_name)
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An Uncommunicative Parameter Name
is a parameter 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.
Cinch::Plugins::Bacon#with_channel_user has the parameter name 'm' Open
def with_channel_user(m, user)
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An Uncommunicative Parameter Name
is a parameter 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.
Ambiguous regexp literal. Parenthesize the method arguments if it's surely a regexp literal, or add a whitespace to the right of the /
if it should be a division. Open
match /bacon$/i, :method => :command_bacon # !bacon
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This cop checks for ambiguous regexp literals in the first argument of a method invocation without parentheses.
Example:
# bad
# This is interpreted as a method invocation with a regexp literal,
# but it could possibly be `/` method invocations.
# (i.e. `do_something./(pattern)./(i)`)
do_something /pattern/i
Example:
# good
# With parentheses, there's no ambiguity.
do_something(/pattern/i)
Ambiguous regexp literal. Parenthesize the method arguments if it's surely a regexp literal, or add a whitespace to the right of the /
if it should be a division. Open
match /bacon\s+(\S+)/i, :method => :command_bacon_gift # !bacon <user>
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This cop checks for ambiguous regexp literals in the first argument of a method invocation without parentheses.
Example:
# bad
# This is interpreted as a method invocation with a regexp literal,
# but it could possibly be `/` method invocations.
# (i.e. `do_something./(pattern)./(i)`)
do_something /pattern/i
Example:
# good
# With parentheses, there's no ambiguity.
do_something(/pattern/i)