Method has too many lines. [23/10] Open
def do_work(args = nil)
results = cache[:results]
params = args[:params]
check_nessesary_constants_set
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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.
Assignment Branch Condition size for do_work is too high. [27.75/15] Open
def do_work(args = nil)
results = cache[:results]
params = args[:params]
check_nessesary_constants_set
- Read upRead up
- Exclude checks
This cop checks that the ABC size of methods is not higher than the configured maximum. The ABC size is based on assignments, branches (method calls), and conditions. See http://c2.com/cgi/wiki?AbcMetric
Perceived complexity for do_work is too high. [10/7] Open
def do_work(args = nil)
results = cache[:results]
params = args[:params]
check_nessesary_constants_set
- Read upRead up
- Exclude checks
This cop tries to produce a complexity score that's a measure of the
complexity the reader experiences when looking at a method. For that
reason it considers when
nodes as something that doesn't add as much
complexity as an if
or a &&
. Except if it's one of those special
case
/when
constructs where there's no expression after case
. Then
the cop treats it as an if
/elsif
/elsif
... and lets all the when
nodes count. In contrast to the CyclomaticComplexity cop, this cop
considers else
nodes as adding complexity.
Example:
def my_method # 1
if cond # 1
case var # 2 (0.8 + 4 * 0.2, rounded)
when 1 then func_one
when 2 then func_two
when 3 then func_three
when 4..10 then func_other
end
else # 1
do_something until a && b # 2
end # ===
end # 7 complexity points
Cyclomatic complexity for do_work is too high. [9/6] Open
def do_work(args = nil)
results = cache[:results]
params = args[:params]
check_nessesary_constants_set
- Read upRead up
- 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 do_work
has a Cognitive Complexity of 6 (exceeds 5 allowed). Consider refactoring. Open
def do_work(args = nil)
results = cache[:results]
params = args[:params]
check_nessesary_constants_set
- Read upRead up
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
Avoid rescuing without specifying an error class. Open
rescue
- Read upRead up
- 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
Use linking.id.positive?
instead of linking.id > 0
. Open
if !linking.nil? && linking && linking.errors.empty? && linking.id > 0
- 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
Prefer $ERROR_INFO
from the stdlib 'English' module (don't forget to require it) over $!
. Open
kete_net_error = $!
- Exclude checks
Unused method argument - args
. If it's necessary, use _
or _args
as an argument name to indicate that it won't be used. You can also write as create(*)
if you want the method to accept any arguments but don't care about them. Open
def create(args = nil)
- Read upRead up
- Exclude checks
This cop checks for unused method arguments.
Example:
# bad
def some_method(used, unused, _unused_but_allowed)
puts used
end
Example:
# good
def some_method(used, _unused, _unused_but_allowed)
puts used
end
Convert if
nested inside else
to elsif
. Open
logger.error('Error linking from Kete.net.nz: ' + kete_net_error) if kete_net_error
- Read upRead up
- Exclude checks
If the else
branch of a conditional consists solely of an if
node,
it can be combined with the else
to become an elsif
.
This helps to keep the nesting level from getting too deep.
Example:
# bad
if condition_a
action_a
else
if condition_b
action_b
else
action_c
end
end
# good
if condition_a
action_a
elsif condition_b
action_b
else
action_c
end