Method create_matcher
has a Cognitive Complexity of 11 (exceeds 5 allowed). Consider refactoring. Open
def create_matcher(conditions, destructure: @destructure, &function)
function ||= IDENTITY
destructurer = Destructurers::Destructurer.new(
destructure: destructure, &function
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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
Qo::Branches::Branch#initialize has boolean parameter 'destructure' Open
def initialize(name:, precondition: Any, extractor: IDENTITY, destructure: false, default: false)
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Boolean Parameter
is a special case of Control Couple
, where a method parameter is defaulted to true or false. A Boolean Parameter effectively permits a method's caller to decide which execution path to take. This is a case of bad cohesion. You're creating a dependency between methods that is not really necessary, thus increasing coupling.
Example
Given
class Dummy
def hit_the_switch(switch = true)
if switch
puts 'Hitting the switch'
# do other things...
else
puts 'Not hitting the switch'
# do other things...
end
end
end
Reek would emit the following warning:
test.rb -- 3 warnings:
[1]:Dummy#hit_the_switch has boolean parameter 'switch' (BooleanParameter)
[2]:Dummy#hit_the_switch is controlled by argument switch (ControlParameter)
Note that both smells are reported, Boolean Parameter
and Control Parameter
.
Getting rid of the smell
This is highly dependent on your exact architecture, but looking at the example above what you could do is:
- Move everything in the
if
branch into a separate method - Move everything in the
else
branch into a separate method - Get rid of the
hit_the_switch
method alltogether - Make the decision what method to call in the initial caller of
hit_the_switch
Qo::Branches::Branch#self.create has boolean parameter 'destructure' Open
def self.create(name:, precondition: Any, extractor: IDENTITY, destructure: false, default: false)
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Boolean Parameter
is a special case of Control Couple
, where a method parameter is defaulted to true or false. A Boolean Parameter effectively permits a method's caller to decide which execution path to take. This is a case of bad cohesion. You're creating a dependency between methods that is not really necessary, thus increasing coupling.
Example
Given
class Dummy
def hit_the_switch(switch = true)
if switch
puts 'Hitting the switch'
# do other things...
else
puts 'Not hitting the switch'
# do other things...
end
end
end
Reek would emit the following warning:
test.rb -- 3 warnings:
[1]:Dummy#hit_the_switch has boolean parameter 'switch' (BooleanParameter)
[2]:Dummy#hit_the_switch is controlled by argument switch (ControlParameter)
Note that both smells are reported, Boolean Parameter
and Control Parameter
.
Getting rid of the smell
This is highly dependent on your exact architecture, but looking at the example above what you could do is:
- Move everything in the
if
branch into a separate method - Move everything in the
else
branch into a separate method - Get rid of the
hit_the_switch
method alltogether - Make the decision what method to call in the initial caller of
hit_the_switch
Qo::Branches::Branch#self.create has boolean parameter 'default' Open
def self.create(name:, precondition: Any, extractor: IDENTITY, destructure: false, default: false)
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- Exclude checks
Boolean Parameter
is a special case of Control Couple
, where a method parameter is defaulted to true or false. A Boolean Parameter effectively permits a method's caller to decide which execution path to take. This is a case of bad cohesion. You're creating a dependency between methods that is not really necessary, thus increasing coupling.
Example
Given
class Dummy
def hit_the_switch(switch = true)
if switch
puts 'Hitting the switch'
# do other things...
else
puts 'Not hitting the switch'
# do other things...
end
end
end
Reek would emit the following warning:
test.rb -- 3 warnings:
[1]:Dummy#hit_the_switch has boolean parameter 'switch' (BooleanParameter)
[2]:Dummy#hit_the_switch is controlled by argument switch (ControlParameter)
Note that both smells are reported, Boolean Parameter
and Control Parameter
.
Getting rid of the smell
This is highly dependent on your exact architecture, but looking at the example above what you could do is:
- Move everything in the
if
branch into a separate method - Move everything in the
else
branch into a separate method - Get rid of the
hit_the_switch
method alltogether - Make the decision what method to call in the initial caller of
hit_the_switch
Qo::Branches::Branch#create_matcher has approx 9 statements Open
def create_matcher(conditions, destructure: @destructure, &function)
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A method with Too Many Statements
is any method that has a large number of lines.
Too Many Statements
warns about any method that has more than 5 statements. Reek's smell detector for Too Many Statements
counts +1 for every simple statement in a method and +1 for every statement within a control structure (if
, else
, case
, when
, for
, while
, until
, begin
, rescue
) but it doesn't count the control structure itself.
So the following method would score +6 in Reek's statement-counting algorithm:
def parse(arg, argv, &error)
if !(val = arg) and (argv.empty? or /\A-/ =~ (val = argv[0]))
return nil, block, nil # +1
end
opt = (val = parse_arg(val, &error))[1] # +2
val = conv_arg(*val) # +3
if opt and !arg
argv.shift # +4
else
val[0] = nil # +5
end
val # +6
end
(You might argue that the two assigments within the first @if@ should count as statements, and that perhaps the nested assignment should count as +2.)
Qo::Branches::Branch has at least 5 instance variables Open
class Branch
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Too Many Instance Variables
is a special case of LargeClass
.
Example
Given this configuration
TooManyInstanceVariables:
max_instance_variables: 3
and this code:
class TooManyInstanceVariables
def initialize
@arg_1 = :dummy
@arg_2 = :dummy
@arg_3 = :dummy
@arg_4 = :dummy
end
end
Reek would emit the following warning:
test.rb -- 5 warnings:
[1]:TooManyInstanceVariables has at least 4 instance variables (TooManyInstanceVariables)
Qo::Branches::Branch#self.create has 5 parameters Open
def self.create(name:, precondition: Any, extractor: IDENTITY, destructure: false, default: false)
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A Long Parameter List
occurs when a method has a lot of parameters.
Example
Given
class Dummy
def long_list(foo,bar,baz,fling,flung)
puts foo,bar,baz,fling,flung
end
end
Reek would report the following warning:
test.rb -- 1 warning:
[2]:Dummy#long_list has 5 parameters (LongParameterList)
A common solution to this problem would be the introduction of parameter objects.
Qo::Branches::Branch#initialize has boolean parameter 'default' Open
def initialize(name:, precondition: Any, extractor: IDENTITY, destructure: false, default: false)
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Boolean Parameter
is a special case of Control Couple
, where a method parameter is defaulted to true or false. A Boolean Parameter effectively permits a method's caller to decide which execution path to take. This is a case of bad cohesion. You're creating a dependency between methods that is not really necessary, thus increasing coupling.
Example
Given
class Dummy
def hit_the_switch(switch = true)
if switch
puts 'Hitting the switch'
# do other things...
else
puts 'Not hitting the switch'
# do other things...
end
end
end
Reek would emit the following warning:
test.rb -- 3 warnings:
[1]:Dummy#hit_the_switch has boolean parameter 'switch' (BooleanParameter)
[2]:Dummy#hit_the_switch is controlled by argument switch (ControlParameter)
Note that both smells are reported, Boolean Parameter
and Control Parameter
.
Getting rid of the smell
This is highly dependent on your exact architecture, but looking at the example above what you could do is:
- Move everything in the
if
branch into a separate method - Move everything in the
else
branch into a separate method - Get rid of the
hit_the_switch
method alltogether - Make the decision what method to call in the initial caller of
hit_the_switch
Qo::Branches::Branch#create_matcher calls 'destructurer.call(extracted_value)' 2 times Open
next [true, destructurer.call(extracted_value)]
end
# Otherwise we check the precondition first before extracting the
# value from whatever container it might be in.
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Duplication occurs when two fragments of code look nearly identical, or when two fragments of code have nearly identical effects at some conceptual level.
Reek implements a check for Duplicate Method Call.
Example
Here's a very much simplified and contrived example. The following method will report a warning:
def double_thing()
@other.thing + @other.thing
end
One quick approach to silence Reek would be to refactor the code thus:
def double_thing()
thing = @other.thing
thing + thing
end
A slightly different approach would be to replace all calls of double_thing
by calls to @other.double_thing
:
class Other
def double_thing()
thing + thing
end
end
The approach you take will depend on balancing other factors in your code.
Qo::Branches::Branch#create_matcher calls '@extractor.call(value)' 2 times Open
extracted_value = @extractor.call(value)
next [true, destructurer.call(extracted_value)]
end
# Otherwise we check the precondition first before extracting the
- Read upRead up
- Exclude checks
Duplication occurs when two fragments of code look nearly identical, or when two fragments of code have nearly identical effects at some conceptual level.
Reek implements a check for Duplicate Method Call.
Example
Here's a very much simplified and contrived example. The following method will report a warning:
def double_thing()
@other.thing + @other.thing
end
One quick approach to silence Reek would be to refactor the code thus:
def double_thing()
thing = @other.thing
thing + thing
end
A slightly different approach would be to replace all calls of double_thing
by calls to @other.double_thing
:
class Other
def double_thing()
thing + thing
end
end
The approach you take will depend on balancing other factors in your code.