FrOData::Properties::Binary#parse_value is controlled by argument 'value' Open
if value == 0 || value == '0' || value == false
- Read upRead up
- Exclude checks
Control Parameter
is a special case of Control Couple
Example
A simple example would be the "quoted" parameter in the following method:
def write(quoted)
if quoted
write_quoted @value
else
write_unquoted @value
end
end
Fixing those problems is out of the scope of this document but an easy solution could be to remove the "write" method alltogether and to move the calls to "writequoted" / "writeunquoted" in the initial caller of "write".
FrOData::Properties::Binary assumes too much for instance variable '@value' Open
class Binary < FrOData::Property
- Read upRead up
- Exclude checks
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.
FrOData::Properties::Binary#parse_value doesn't depend on instance state (maybe move it to another class?) Open
def parse_value(value)
- Read upRead up
- Exclude checks
A Utility Function is any instance method that has no dependency on the state of the instance.
FrOData::Properties::Binary#value performs a nil-check Open
if (@value.nil? || @value.empty?) && allows_nil?
- Read upRead up
- Exclude checks
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)
Space missing after comma. Open
unless [0,1,'0','1',true,false].include?(value)
- Read upRead up
- Exclude checks
Checks for comma (,) not followed by some kind of space.
Example:
# bad
[1,2]
{ foo:bar,}
# good
[1, 2]
{ foo:bar, }
Space missing after comma. Open
unless [0,1,'0','1',true,false].include?(value)
- Read upRead up
- Exclude checks
Checks for comma (,) not followed by some kind of space.
Example:
# bad
[1,2]
{ foo:bar,}
# good
[1, 2]
{ foo:bar, }
Use a guard clause instead of wrapping the code inside a conditional expression. Open
unless [0,1,'0','1',true,false].include?(value)
- Read upRead up
- Exclude checks
Use a guard clause instead of wrapping the code inside a conditional expression
Example:
# bad
def test
if something
work
end
end
# good
def test
return unless something
work
end
# also good
def test
work if something
end
# bad
if something
raise 'exception'
else
ok
end
# good
raise 'exception' if something
ok
Space missing after comma. Open
unless [0,1,'0','1',true,false].include?(value)
- Read upRead up
- Exclude checks
Checks for comma (,) not followed by some kind of space.
Example:
# bad
[1,2]
{ foo:bar,}
# good
[1, 2]
{ foo:bar, }
Use value.zero?
instead of value == 0
. Open
if value == 0 || value == '0' || value == false
- Read upRead up
- Exclude checks
This cop checks for usage of comparison operators (==
,
>
, <
) to test numbers as zero, positive, or negative.
These can be replaced by their respective predicate methods.
The cop can also be configured to do the reverse.
The cop disregards #nonzero?
as it its value is truthy or falsey,
but not true
and false
, and thus not always interchangeable with
!= 0
.
The cop ignores comparisons to global variables, since they are often
populated with objects which can be compared with integers, but are
not themselves Interger
polymorphic.
Example: EnforcedStyle: predicate (default)
# bad
foo == 0
0 > foo
bar.baz > 0
# good
foo.zero?
foo.negative?
bar.baz.positive?
Example: EnforcedStyle: comparison
# bad
foo.zero?
foo.negative?
bar.baz.positive?
# good
foo == 0
0 > foo
bar.baz > 0
Space missing after comma. Open
unless [0,1,'0','1',true,false].include?(value)
- Read upRead up
- Exclude checks
Checks for comma (,) not followed by some kind of space.
Example:
# bad
[1,2]
{ foo:bar,}
# good
[1, 2]
{ foo:bar, }
Space missing after comma. Open
unless [0,1,'0','1',true,false].include?(value)
- Read upRead up
- Exclude checks
Checks for comma (,) not followed by some kind of space.
Example:
# bad
[1,2]
{ foo:bar,}
# good
[1, 2]
{ foo:bar, }
Avoid comparing a variable with multiple items in a conditional, use Array#include?
instead. Open
if value == 0 || value == '0' || value == false
'0'
else
'1'
end
- Read upRead up
- Exclude checks
This cop checks against comparing a variable with multiple items, where
Array#include?
could be used instead to avoid code repetition.
Example:
# bad
a = 'a'
foo if a == 'a' || a == 'b' || a == 'c'
# good
a = 'a'
foo if ['a', 'b', 'c'].include?(a)