Method has too many lines. [13/10] Open
def dup
super.tap do |new_config|
new_config.instance_variable_set(
:@_nested,
Hash[
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- Exclude checks
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.
Method _add
has a Cognitive Complexity of 6 (exceeds 5 allowed). Consider refactoring. Open
def _add(key, *args, &block)
raise NotAddableError, self.inspect if @_value && !@_value.is_a?(Array)
object = _args_to_object(*args, &block)
_set(key, object.is_a?(Proc) ? ProcArray.new : []) if !_get(key)
_get(key).push(object)
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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
Use =~
in places where the MatchData
returned by #match
will not be used. Open
if /^(\w+)\=$/.match(meth_str)
- Read upRead up
- Exclude checks
This cop identifies the use of Regexp#match
or String#match
, which
returns #<MatchData>
/nil
. The return value of =~
is an integral
index/nil
and is more performant.
Example:
# bad
do_something if str.match(/regex/)
while regex.match('str')
do_something
end
# good
method(str =~ /regex/)
return value unless regex =~ 'str'
Use yield
instead of block.call
. Open
when 1 then block.call(self)
- Read upRead up
- Exclude checks
This cop identifies the use of a &block
parameter and block.call
where yield
would do just as well.
Example:
# bad
def method(&block)
block.call
end
def another(&func)
func.call 1, 2, 3
end
# good
def method
yield
end
def another
yield 1, 2, 3
end
Use =~
in places where the MatchData
returned by #match
will not be used. Open
elsif /^(\w+)\?$/.match(meth_str)
- Read upRead up
- Exclude checks
This cop identifies the use of Regexp#match
or String#match
, which
returns #<MatchData>
/nil
. The return value of =~
is an integral
index/nil
and is more performant.
Example:
# bad
do_something if str.match(/regex/)
while regex.match('str')
do_something
end
# good
method(str =~ /regex/)
return value unless regex =~ 'str'
Avoid the use of Perl-style backrefs. Open
_set($1, *args, &block)
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- Exclude checks
This cop looks for uses of Perl-style regexp match backreferences like $1, $2, etc.
Example:
# bad
puts $1
# good
puts Regexp.last_match(1)
Do not place comments on the same line as the end
keyword. Open
end # Announcer
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- Exclude checks
This cop checks for comments put on the same line as some keywords.
These keywords are: begin
, class
, def
, end
, module
.
Note that some comments (such as :nodoc:
and rubocop:disable
) are
allowed.
Example:
# bad
if condition
statement
end # end if
# bad
class X # comment
statement
end
# bad
def x; end # comment
# good
if condition
statement
end
# good
class X # :nodoc:
y
end
Surrounding space missing in default value assignment. Open
def initialize(name=nil, &block)
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- Exclude checks
Checks that the equals signs in parameter default assignments have or don't have surrounding space depending on configuration.
Example:
# bad
def some_method(arg1=:default, arg2=nil, arg3=[])
# do something...
end
# good
def some_method(arg1 = :default, arg2 = nil, arg3 = [])
# do something...
end
When using method_missing
, define respond_to_missing?
and fall back on super
. Open
def method_missing(meth, *args, &block)
meth_str = meth.to_s
if /^(\w+)\=$/.match(meth_str)
_set($1, *args, &block)
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- Exclude checks
This cop checks for the presence of method_missing
without also
defining respond_to_missing?
and falling back on super
.
Example:
#bad
def method_missing(name, *args)
# ...
end
#good
def respond_to_missing?(name, include_private)
# ...
end
def method_missing(name, *args)
# ...
super
end
Redundant self
detected. Open
raise NotAddableError, self.inspect if @_value && !@_value.is_a?(Array)
- Read upRead up
- Exclude checks
This cop checks for redundant uses of self
.
The usage of self
is only needed when:
Sending a message to same object with zero arguments in presence of a method name clash with an argument or a local variable.
Calling an attribute writer to prevent an local variable assignment.
Note, with using explicit self you can only send messages with public or protected scope, you cannot send private messages this way.
Note we allow uses of self
with operators because it would be awkward
otherwise.
Example:
# bad
def foo(bar)
self.baz
end
# good
def foo(bar)
self.bar # Resolves name clash with the argument.
end
def foo
bar = 1
self.bar # Resolves name clash with the local variable.
end
def foo
%w[x y z].select do |bar|
self.bar == bar # Resolves name clash with argument of the block.
end
end
Avoid the use of Perl-style backrefs. Open
!!_get($1)
- Read upRead up
- 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)
Prefer single-quoted strings when you don't need string interpolation or special symbols. Open
raise ConfigError, "May only add blocks" unless procs.all? { |p| p.is_a?(Proc) }
- Read upRead up
- Exclude checks
Checks if uses of quotes match the configured preference.
Example: EnforcedStyle: single_quotes (default)
# bad
"No special symbols"
"No string interpolation"
"Just text"
# good
'No special symbols'
'No string interpolation'
'Just text'
"Wait! What's #{this}!"
Example: EnforcedStyle: double_quotes
# bad
'Just some text'
'No special chars or interpolation'
# good
"Just some text"
"No special chars or interpolation"
"Every string in #{project} uses double_quotes"
Use !empty?
instead of length > 0
. Open
elsif args.length > 0 || block_given?
- Read upRead up
- Exclude checks
This cop checks for numeric comparisons that can be replaced by a predicate method, such as receiver.length == 0, receiver.length > 0, receiver.length != 0, receiver.length < 1 and receiver.size == 0 that can be replaced by receiver.empty? and !receiver.empty.
Example:
# bad
[1, 2, 3].length == 0
0 == "foobar".length
array.length < 1
{a: 1, b: 2}.length != 0
string.length > 0
hash.size > 0
# good
[1, 2, 3].empty?
"foobar".empty?
array.empty?
!{a: 1, b: 2}.empty?
!string.empty?
!hash.empty?
Missing top-level class documentation comment. Open
class Config
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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
Missing top-level class documentation comment. Open
class ProcArray < Array
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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
Line is too long. [88/80] Open
raise ConfigError, "May only add blocks" unless procs.all? { |p| p.is_a?(Proc) }
- Exclude checks
Do not place comments on the same line as the end
keyword. Open
end # Config
- Read upRead up
- Exclude checks
This cop checks for comments put on the same line as some keywords.
These keywords are: begin
, class
, def
, end
, module
.
Note that some comments (such as :nodoc:
and rubocop:disable
) are
allowed.
Example:
# bad
if condition
statement
end # end if
# bad
class X # comment
statement
end
# bad
def x; end # comment
# good
if condition
statement
end
# good
class X # :nodoc:
y
end
Keep a blank line before and after private
. Open
private
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- Exclude checks
Access modifiers should be surrounded by blank lines.
Example:
# bad
class Foo
def bar; end
private
def baz; end
end
# good
class Foo
def bar; end
private
def baz; end
end
Avoid using {...}
for multi-line blocks. Open
hash.each { |k, v|
- Read upRead up
- Exclude checks
Check for uses of braces or do/end around single line or multi-line blocks.
Example: EnforcedStyle: linecountbased (default)
# bad - single line block
items.each do |item| item / 5 end
# good - single line block
items.each { |item| item / 5 }
# bad - multi-line block
things.map { |thing|
something = thing.some_method
process(something)
}
# good - multi-line block
things.map do |thing|
something = thing.some_method
process(something)
end
Example: EnforcedStyle: semantic
# Prefer `do...end` over `{...}` for procedural blocks.
# return value is used/assigned
# bad
foo = map do |x|
x
end
puts (map do |x|
x
end)
# return value is not used out of scope
# good
map do |x|
x
end
# Prefer `{...}` over `do...end` for functional blocks.
# return value is not used out of scope
# bad
each { |x|
x
}
# return value is used/assigned
# good
foo = map { |x|
x
}
map { |x|
x
}.inspect
Example: EnforcedStyle: bracesforchaining
# bad
words.each do |word|
word.flip.flop
end.join("-")
# good
words.each { |word|
word.flip.flop
}.join("-")
Favor unless
over if
for negative conditions. Open
_set(key, object.is_a?(Proc) ? ProcArray.new : []) if !_get(key)
- Read upRead up
- Exclude checks
Checks for uses of if with a negated condition. Only ifs without else are considered. There are three different styles:
- both
- prefix
- postfix
Example: EnforcedStyle: both (default)
# enforces `unless` for `prefix` and `postfix` conditionals
# bad
if !foo
bar
end
# good
unless foo
bar
end
# bad
bar if !foo
# good
bar unless foo
Example: EnforcedStyle: prefix
# enforces `unless` for just `prefix` conditionals
# bad
if !foo
bar
end
# good
unless foo
bar
end
# good
bar if !foo
Example: EnforcedStyle: postfix
# enforces `unless` for just `postfix` conditionals
# bad
bar if !foo
# good
bar unless foo
# good
if !foo
bar
end
Missing top-level class documentation comment. Open
class UndefinedValue
- Read upRead up
- 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
Avoid using {...}
for multi-line blocks. Open
_nested.map { |key, object|
- Read upRead up
- Exclude checks
Check for uses of braces or do/end around single line or multi-line blocks.
Example: EnforcedStyle: linecountbased (default)
# bad - single line block
items.each do |item| item / 5 end
# good - single line block
items.each { |item| item / 5 }
# bad - multi-line block
things.map { |thing|
something = thing.some_method
process(something)
}
# good - multi-line block
things.map do |thing|
something = thing.some_method
process(something)
end
Example: EnforcedStyle: semantic
# Prefer `do...end` over `{...}` for procedural blocks.
# return value is used/assigned
# bad
foo = map do |x|
x
end
puts (map do |x|
x
end)
# return value is not used out of scope
# good
map do |x|
x
end
# Prefer `{...}` over `do...end` for functional blocks.
# return value is not used out of scope
# bad
each { |x|
x
}
# return value is used/assigned
# good
foo = map { |x|
x
}
map { |x|
x
}.inspect
Example: EnforcedStyle: bracesforchaining
# bad
words.each do |word|
word.flip.flop
end.join("-")
# good
words.each { |word|
word.flip.flop
}.join("-")
Avoid the use of double negation (!!
). Open
!!_get($1)
- Read upRead up
- Exclude checks
This cop checks for uses of double negation (!!) to convert something to a boolean value. As this is both cryptic and usually redundant, it should be avoided.
Example:
# bad
!!something
# good
!something.nil?
Please, note that when something is a boolean value !!something and !something.nil? are not the same thing. As you're unlikely to write code that can accept values of any type this is rarely a problem in practice.