EstimationsController assumes too much for instance variable '@estimation' Open
class EstimationsController < ApplicationController
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Classes should not assume that instance variables are set or present outside of the current class definition.
Good:
class Foo
def initialize
@bar = :foo
end
def foo?
@bar == :foo
end
end
Good as well:
class Foo
def foo?
bar == :foo
end
def bar
@bar ||= :foo
end
end
Bad:
class Foo
def go_foo!
@bar = :foo
end
def foo?
@bar == :foo
end
end
Example
Running Reek on:
class Dummy
def test
@ivar
end
end
would report:
[1]:InstanceVariableAssumption: Dummy assumes too much for instance variable @ivar
Note that this example would trigger this smell warning as well:
class Parent
def initialize(omg)
@omg = omg
end
end
class Child < Parent
def foo
@omg
end
end
The way to address the smell warning is that you should create an attr_reader
to use @omg
in the subclass and not access @omg
directly like this:
class Parent
attr_reader :omg
def initialize(omg)
@omg = omg
end
end
class Child < Parent
def foo
omg
end
end
Directly accessing instance variables is considered a smell because it breaks encapsulation and makes it harder to reason about code.
If you don't want to expose those methods as public API just make them private like this:
class Parent
def initialize(omg)
@omg = omg
end
private
attr_reader :omg
end
class Child < Parent
def foo
omg
end
end
Current Support in Reek
An instance variable must:
- be set in the constructor
- or be accessed through a method with lazy initialization / memoization.
If not, Instance Variable Assumption will be reported.
Keep a blank line before and after private
. Open
private
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Access modifiers should be surrounded by blank lines.
Example: EnforcedStyle: around (default)
# bad
class Foo
def bar; end
private
def baz; end
end
# good
class Foo
def bar; end
private
def baz; end
end
Example: EnforcedStyle: only_before
# bad
class Foo
def bar; end
private
def baz; end
end
# good
class Foo
def bar; end
private
def baz; end
end
Missing frozen string literal comment. Open
# == Schema Information
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Helps you transition from mutable string literals
to frozen string literals.
It will add the # frozen_string_literal: true
magic comment to the top
of files to enable frozen string literals. Frozen string literals may be
default in future Ruby. The comment will be added below a shebang and
encoding comment. The frozen string literal comment is only valid in Ruby 2.3+.
Note that the cop will accept files where the comment exists but is set
to false
instead of true
.
To require a blank line after this comment, please see
Layout/EmptyLineAfterMagicComment
cop.
Safety:
This cop's autocorrection is unsafe since any strings mutations will
change from being accepted to raising FrozenError
, as all strings
will become frozen by default, and will need to be manually refactored.
Example: EnforcedStyle: always (default)
# The `always` style will always add the frozen string literal comment
# to a file, regardless of the Ruby version or if `freeze` or `<<` are
# called on a string literal.
# bad
module Bar
# ...
end
# good
# frozen_string_literal: true
module Bar
# ...
end
# good
# frozen_string_literal: false
module Bar
# ...
end
Example: EnforcedStyle: never
# The `never` will enforce that the frozen string literal comment does
# not exist in a file.
# bad
# frozen_string_literal: true
module Baz
# ...
end
# good
module Baz
# ...
end
Example: EnforcedStyle: always_true
# The `always_true` style enforces that the frozen string literal
# comment is set to `true`. This is a stricter option than `always`
# and forces projects to use frozen string literals.
# bad
# frozen_string_literal: false
module Baz
# ...
end
# bad
module Baz
# ...
end
# good
# frozen_string_literal: true
module Bar
# ...
end
Missing top-level documentation comment for class EstimationsController
. Open
class EstimationsController < ApplicationController
- Read upRead up
- Exclude checks
Checks for missing top-level documentation of classes and modules. Classes with no body are exempt from the check and so are namespace modules - modules that have nothing in their bodies except classes, other modules, constant definitions or constant visibility declarations.
The documentation requirement is annulled if the class or module has
a #:nodoc:
comment next to it. Likewise, #:nodoc: all
does the
same for all its children.
Example:
# bad
class Person
# ...
end
module Math
end
# good
# Description/Explanation of Person class
class Person
# ...
end
# allowed
# Class without body
class Person
end
# Namespace - A namespace can be a class or a module
# Containing a class
module Namespace
# Description/Explanation of Person class
class Person
# ...
end
end
# Containing constant visibility declaration
module Namespace
class Private
end
private_constant :Private
end
# Containing constant definition
module Namespace
Public = Class.new
end
# Macro calls
module Namespace
extend Foo
end
Example: AllowedConstants: ['ClassMethods']
# good
module A
module ClassMethods
# ...
end
end