UsersController has at least 7 instance variables Open
class UsersController < ApplicationController
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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)
UsersController#show has approx 7 statements Open
def show
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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.)
Complex method UsersController#show (24.5) Open
def show
user_talks = @user.talks.publics
talks = user_talks.order(created_at: :desc).to_a
@events = @user.events.publics.order(start_date: :desc).to_a
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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
Assignment Branch Condition size for show is too high. [<8, 19, 0> 20.62/17] Open
def show
user_talks = @user.talks.publics
talks = user_talks.order(created_at: :desc).to_a
@events = @user.events.publics.order(start_date: :desc).to_a
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This cop checks that the ABC size of methods is not higher than the configured maximum. The ABC size is based on assignments, branches (method calls), and conditions. See http://c2.com/cgi/wiki?AbcMetric and https://en.wikipedia.org/wiki/ABC_Software_Metric.
Interpreting ABC size:
- <= 17 satisfactory
- 18..30 unsatisfactory
- > 30 dangerous
You can have repeated "attributes" calls count as a single "branch".
For this purpose, attributes are any method with no argument; no attempt
is meant to distinguish actual attr_reader
from other methods.
Example: CountRepeatedAttributes: false (default is true)
# `model` and `current_user`, refenced 3 times each,
# are each counted as only 1 branch each if
# `CountRepeatedAttributes` is set to 'false'
def search
@posts = model.active.visible_by(current_user)
.search(params[:q])
@posts = model.some_process(@posts, current_user)
@posts = model.another_process(@posts, current_user)
render 'pages/search/page'
end
This cop also takes into account IgnoredMethods
(defaults to []
)