Complex method BulkTransfer#each_transfer (38.9) Open
def each_transfer # rubocop:todo Metrics/AbcSize, Metrics/MethodLength
well_transfers
.group_by { |tf| [tf['source_uuid'], tf['destination_uuid']] }
.each do |source_dest, all_transfers|
transfers = Hash.new { |h, i| h[i] = [] }
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Flog calculates the ABC score for methods. The ABC score is based on assignments, branches (method calls), and conditions.
You can read more about ABC metrics or the flog tool
BulkTransfer#each_transfer contains iterators nested 2 deep Open
transfers = Hash.new { |h, i| h[i] = [] }
all_transfers.each { |t| transfers[t['source_location']] << t['destination_location'] }
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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)
BulkTransfer#each_transfer has approx 12 statements Open
def each_transfer # rubocop:todo Metrics/AbcSize, Metrics/MethodLength
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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.)
Method each_transfer
has a Cognitive Complexity of 8 (exceeds 5 allowed). Consider refactoring. Open
def each_transfer # rubocop:todo Metrics/AbcSize, Metrics/MethodLength
well_transfers
.group_by { |tf| [tf['source_uuid'], tf['destination_uuid']] }
.each do |source_dest, all_transfers|
transfers = Hash.new { |h, i| h[i] = [] }
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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
BulkTransfer has missing safe method 'build_transfers!' Open
def build_transfers!
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A candidate method for the Missing Safe Method
smell are methods whose names end with an exclamation mark.
An exclamation mark in method names means (the explanation below is taken from here ):
The ! in method names that end with ! means, “This method is dangerous”—or, more precisely, this method is the “dangerous” version of an otherwise equivalent method, with the same name minus the !. “Danger” is relative; the ! doesn’t mean anything at all unless the method name it’s in corresponds to a similar but bang-less method name. So, for example, gsub! is the dangerous version of gsub. exit! is the dangerous version of exit. flatten! is the dangerous version of flatten. And so forth.
Such a method is called Missing Safe Method
if and only if her non-bang version does not exist and this method is reported as a smell.
Example
Given
class C
def foo; end
def foo!; end
def bar!; end
end
Reek would report bar!
as Missing Safe Method
smell but not foo!
.
Reek reports this smell only in a class context, not in a module context in order to allow perfectly legit code like this:
class Parent
def foo; end
end
module Dangerous
def foo!; end
end
class Son < Parent
include Dangerous
end
class Daughter < Parent
end
In this example, Reek would not report the Missing Safe Method
smell for the method foo
of the Dangerous
module.
BulkTransfer#well_transfers is a writable attribute Open
attr_accessor :well_transfers
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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)
BulkTransfer#each_transfer has the variable name 'i' Open
transfers = Hash.new { |h, i| h[i] = [] }
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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.
BulkTransfer#each_transfer has the variable name 'h' Open
transfers = Hash.new { |h, i| h[i] = [] }
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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.
BulkTransfer#each_transfer has the variable name 't' Open
all_transfers.each { |t| transfers[t['source_location']] << t['destination_location'] }
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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.