Class has too many lines. [102/100] Open
class Base < FrOData::Property
# The SRID (Spatial Reference ID) of this property.
attr_accessor :srid
# The default SRID (same as used by GPS)
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This cop checks if the length a class exceeds some maximum value. Comment lines can optionally be ignored. The maximum allowed length is configurable.
Method has too many lines. [13/10] Open
def value_to_xml(value, xml_builder)
if value.is_a?(Hash)
value.each do |key, val|
xml_builder['gml'].send(key) do
value_to_xml(val, xml_builder)
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This cop checks if the length of a method exceeds some maximum value. Comment lines can optionally be ignored. The maximum allowed length is configurable.
FrOData::Properties::Geography::Base#value_to_xml has approx 6 statements Open
def value_to_xml(value, xml_builder)
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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.)
FrOData::Properties::Geography::Base#value_to_xml refers to 'value' more than self (maybe move it to another class?) Open
if value.is_a?(Hash)
value.each do |key, val|
xml_builder['gml'].send(key) do
value_to_xml(val, xml_builder)
end
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Feature Envy occurs when a code fragment references another object more often than it references itself, or when several clients do the same series of manipulations on a particular type of object.
Feature Envy reduces the code's ability to communicate intent: code that "belongs" on one class but which is located in another can be hard to find, and may upset the "System of Names" in the host class.
Feature Envy also affects the design's flexibility: A code fragment that is in the wrong class creates couplings that may not be natural within the application's domain, and creates a loss of cohesion in the unwilling host class.
Feature Envy often arises because it must manipulate other objects (usually its arguments) to get them into a useful form, and one force preventing them (the arguments) doing this themselves is that the common knowledge lives outside the arguments, or the arguments are of too basic a type to justify extending that type. Therefore there must be something which 'knows' about the contents or purposes of the arguments. That thing would have to be more than just a basic type, because the basic types are either containers which don't know about their contents, or they are single objects which can't capture their relationship with their fellows of the same type. So, this thing with the extra knowledge should be reified into a class, and the utility method will most likely belong there.
Example
Running Reek on:
class Warehouse
def sale_price(item)
(item.price - item.rebate) * @vat
end
end
would report:
Warehouse#total_price refers to item more than self (FeatureEnvy)
since this:
(item.price - item.rebate)
belongs to the Item class, not the Warehouse.
FrOData::Properties::Geography::Base#value_to_xml calls 'value.each' 2 times Open
value.each do |key, val|
xml_builder['gml'].send(key) do
value_to_xml(val, xml_builder)
end
end
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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.
FrOData::Properties::Geography::Base has no descriptive comment Open
class Base < FrOData::Property
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Classes and modules are the units of reuse and release. It is therefore considered good practice to annotate every class and module with a brief comment outlining its responsibilities.
Example
Given
class Dummy
# Do things...
end
Reek would emit the following warning:
test.rb -- 1 warning:
[1]:Dummy has no descriptive comment (IrresponsibleModule)
Fixing this is simple - just an explaining comment:
# The Dummy class is responsible for ...
class Dummy
# Do things...
end
FrOData::Properties::Geography::Base#value_to_xml calls 'value_to_xml(val, xml_builder)' 2 times Open
value_to_xml(val, xml_builder)
end
end
elsif value.is_a?(Array)
value.each do |val|
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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.
Method parse_wkt
has a Cognitive Complexity of 6 (exceeds 5 allowed). Consider refactoring. Open
def parse_wkt(value)
if value =~ /^geography'(SRID=(\d+);)+(\w+)\((.+)\)'$/
$3 == type_name or raise ArgumentError, "Invalid geography type '#{$3}'"
self.srid = $1 ? $2.to_i : DEFAULT_SRID
coords_from_s($4)
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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
FrOData::Properties::Geography::Base#value= performs a nil-check Open
if value.nil? && allows_nil?
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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)
FrOData::Properties::Geography::Base#srid is a writable attribute Open
attr_accessor :srid
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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)
Use options[:srid] = srid_from_xml(property_xml)
instead of options.merge!(srid: srid_from_xml(property_xml))
. Open
options.merge!(srid: srid_from_xml(property_xml))
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This cop identifies places where Hash#merge!
can be replaced by
Hash#[]=
.
Example:
hash.merge!(a: 1)
hash.merge!({'key' => 'value'})
hash.merge!(a: 1, b: 2)
Use the return of the conditional for variable assignment and comparison. Open
if value.nil? && allows_nil?
@value = nil
elsif value.is_a?(Hash)
@value = value['coordinates']
elsif value.is_a?(Array)
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Use ||
instead of or
. Open
$3 == type_name or raise ArgumentError, "Invalid geography type '#{$3}'"
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This cop checks for uses of and
and or
, and suggests using &&
and
|| instead
. It can be configured to check only in conditions, or in
all contexts.
Example: EnforcedStyle: always (default)
# bad
foo.save and return
# bad
if foo and bar
end
# good
foo.save && return
# good
if foo && bar
end
Example: EnforcedStyle: conditionals
# bad
if foo and bar
end
# good
foo.save && return
# good
foo.save and return
# good
if foo && bar
end
Use a guard clause instead of wrapping the code inside a conditional expression. Open
if srs_attr
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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
Avoid the use of Perl-style backrefs. Open
self.srid = $1 ? $2.to_i : DEFAULT_SRID
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This cop looks for uses of Perl-style regexp match backreferences like $1, $2, etc.
Example:
# bad
puts $1
# good
puts Regexp.last_match(1)
Use %r
around regular expression. Open
srs_attr.value.split(/[\/:]/).last.to_i
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- Exclude checks
This cop enforces using // or %r around regular expressions.
Example: EnforcedStyle: slashes (default)
# bad
snake_case = %r{^[\dA-Z_]+$}
# bad
regex = %r{
foo
(bar)
(baz)
}x
# good
snake_case = /^[\dA-Z_]+$/
# good
regex = /
foo
(bar)
(baz)
/x
Example: EnforcedStyle: percent_r
# bad
snake_case = /^[\dA-Z_]+$/
# bad
regex = /
foo
(bar)
(baz)
/x
# good
snake_case = %r{^[\dA-Z_]+$}
# good
regex = %r{
foo
(bar)
(baz)
}x
Example: EnforcedStyle: mixed
# bad
snake_case = %r{^[\dA-Z_]+$}
# bad
regex = /
foo
(bar)
(baz)
/x
# good
snake_case = /^[\dA-Z_]+$/
# good
regex = %r{
foo
(bar)
(baz)
}x
Example: AllowInnerSlashes: false (default)
# If `false`, the cop will always recommend using `%r` if one or more
# slashes are found in the regexp string.
# bad
x =~ /home\//
# good
x =~ %r{home/}
Example: AllowInnerSlashes: true
# good
x =~ /home\//
protected
(on line 118) does not make singleton methods protected. Use protected
inside a class << self
block instead. Open
def self.srid_from_xml(property_xml)
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This cop checks for private
or protected
access modifiers which are
applied to a singleton method. These access modifiers do not make
singleton methods private/protected. private_class_method
can be
used for that.
Example:
# bad
class C
private
def self.method
puts 'hi'
end
end
Example:
# good
class C
def self.method
puts 'hi'
end
private_class_method :method
end
Example:
# good
class C
class << self
private
def method
puts 'hi'
end
end
end
Use a guard clause instead of wrapping the code inside a conditional expression. Open
if value =~ /^geography'(SRID=(\d+);)+(\w+)\((.+)\)'$/
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- 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
Avoid the use of Perl-style backrefs. Open
self.srid = $1 ? $2.to_i : DEFAULT_SRID
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- Exclude checks
This cop looks for uses of Perl-style regexp match backreferences like $1, $2, etc.
Example:
# bad
puts $1
# good
puts Regexp.last_match(1)
Avoid the use of Perl-style backrefs. Open
$3 == type_name or raise ArgumentError, "Invalid geography type '#{$3}'"
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- Exclude checks
This cop looks for uses of Perl-style regexp match backreferences like $1, $2, etc.
Example:
# bad
puts $1
# good
puts Regexp.last_match(1)
Use a guard clause instead of wrapping the code inside a conditional expression. Open
if srid == DEFAULT_SRID
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- 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
Favor modifier if
usage when having a single-line body. Another good alternative is the usage of control flow &&
/||
. Open
if srs_attr
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Checks for if and unless statements that would fit on one line
if written as a modifier if/unless. The maximum line length is
configured in the Metrics/LineLength
cop.
Example:
# bad
if condition
do_stuff(bar)
end
unless qux.empty?
Foo.do_something
end
# good
do_stuff(bar) if condition
Foo.do_something unless qux.empty?
Avoid the use of Perl-style backrefs. Open
$3 == type_name or raise ArgumentError, "Invalid geography type '#{$3}'"
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- Exclude checks
This cop looks for uses of Perl-style regexp match backreferences like $1, $2, etc.
Example:
# bad
puts $1
# good
puts Regexp.last_match(1)
Use a guard clause instead of wrapping the code inside a conditional expression. Open
if srid == DEFAULT_SRID
- 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
Avoid the use of Perl-style backrefs. Open
coords_from_s($4)
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- Exclude checks
This cop looks for uses of Perl-style regexp match backreferences like $1, $2, etc.
Example:
# bad
puts $1
# good
puts Regexp.last_match(1)
Line is too long. [84/80] Open
$3 == type_name or raise ArgumentError, "Invalid geography type '#{$3}'"
- Exclude checks
Missing top-level class documentation comment. Open
class Base < FrOData::Property
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- Exclude checks
This cop 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, or constant definitions.
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
# good
# Description/Explanation of Person class
class Person
# ...
end