Cyclomatic complexity for for is too high. [9/7] Open
def for(location: nil, uid: nil, node: nil)
unless node
node = Node.find_by_location_on_network(location) if location
node = Node.find_by_uid(uid) if uid && !node
end
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- Exclude checks
This cop checks that the cyclomatic complexity of methods is not higher than the configured maximum. The cyclomatic complexity is the number of linearly independent paths through a method. The algorithm counts decision points and adds one.
An if statement (or unless or ?:) increases the complexity by one. An else branch does not, since it doesn't add a decision point. The && operator (or keyword and) can be converted to a nested if statement, and ||/or is shorthand for a sequence of ifs, so they also add one. Loops can be said to have an exit condition, so they add one.
Method for
has a Cognitive Complexity of 11 (exceeds 5 allowed). Consider refactoring. Open
def for(location: nil, uid: nil, node: nil)
unless node
node = Node.find_by_location_on_network(location) if location
node = Node.find_by_uid(uid) if uid && !node
end
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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
Add an empty line after magic comments. (https://github.com/bbatsov/ruby-style-guide#separate-magic-comments-from-code) Open
module Meshchat
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- Exclude checks
Checks for a newline after the final magic comment.
Example:
# good
# frozen_string_literal: true
# Some documentation for Person
class Person
# Some code
end
# bad
# frozen_string_literal: true
# Some documentation for Person
class Person
# Some code
end
Empty line detected around arguments. Open
is_domain ? DOMAIN_WITH_PORT : IPV4_WITH_PORT
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- Exclude checks
This cops checks if empty lines exist around the arguments of a method invocation.
Example:
# bad
do_something(
foo
)
process(bar,
baz: qux,
thud: fred)
some_method(
[1,2,3],
x: y
)
# good
do_something(
foo
)
process(bar,
baz: qux,
thud: fred)
some_method(
[1,2,3],
x: y
)
Favor modifier if
usage when having a single-line body. Another good alternative is the usage of control flow &&
/||
. (https://github.com/bbatsov/ruby-style-guide#if-as-a-modifier) Open
if other.is_a?(Hash)
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- Exclude checks
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?
Use safe navigation (&.
) instead of checking if an object exists before calling the method. Open
unless node && node.valid?
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- Exclude checks
This cop transforms usages of a method call safeguarded by a non nil
check for the variable whose method is being called to
safe navigation (&.
).
Configuration option: ConvertCodeThatCanStartToReturnNil
The default for this is false
. When configured to true
, this will
check for code in the format !foo.nil? && foo.bar
. As it is written,
the return of this code is limited to false
and whatever the return
of the method is. If this is converted to safe navigation,
foo&.bar
can start returning nil
as well as what the method
returns.
Example:
# bad
foo.bar if foo
foo.bar(param1, param2) if foo
foo.bar { |e| e.something } if foo
foo.bar(param) { |e| e.something } if foo
foo.bar if !foo.nil?
foo.bar unless !foo
foo.bar unless foo.nil?
foo && foo.bar
foo && foo.bar(param1, param2)
foo && foo.bar { |e| e.something }
foo && foo.bar(param) { |e| e.something }
# good
foo&.bar
foo&.bar(param1, param2)
foo&.bar { |e| e.something }
foo&.bar(param) { |e| e.something }
foo.nil? || foo.bar
!foo || foo.bar
# Methods that `nil` will `respond_to?` should not be converted to
# use safe navigation
foo.to_i if foo
Use %r
around regular expression. (https://github.com/bbatsov/ruby-style-guide#percent-r) Open
DOMAIN_WITH_PORT = /(https?:\/\/)?([\da-z\.-]+)\.?([a-z\.]{2,6})([\/\w \.-]*)*[^\/](:\d*)?/
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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\//
Avoid rescuing without specifying an error class. Open
rescue => e
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- Exclude checks
This cop checks for rescuing StandardError
. There are two supported
styles implicit
and explicit
. This cop will not register an offense
if any error other than StandardError
is specified.
Example: EnforcedStyle: implicit
# `implicit` will enforce using `rescue` instead of
# `rescue StandardError`.
# bad
begin
foo
rescue StandardError
bar
end
# good
begin
foo
rescue
bar
end
# good
begin
foo
rescue OtherError
bar
end
# good
begin
foo
rescue StandardError, SecurityError
bar
end
Example: EnforcedStyle: explicit (default)
# `explicit` will enforce using `rescue StandardError`
# instead of `rescue`.
# bad
begin
foo
rescue
bar
end
# good
begin
foo
rescue StandardError
bar
end
# good
begin
foo
rescue OtherError
bar
end
# good
begin
foo
rescue StandardError, SecurityError
bar
end