Cyclomatic complexity for sync_workers is too high. [14/11] Open
def sync_workers
ws = find_current_or_starting
current = ws.collect(&:queue_name).sort
desired = has_required_role? ? desired_queue_names.sort : []
result = {:adds => [], :deletes => []}
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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. Blocks that are calls to builtin iteration methods (e.g. `ary.map{...}) also add one, others are ignored.
def each_child_node(*types) # count begins: 1
unless block_given? # unless: +1
return to_enum(__method__, *types)
children.each do |child| # each{}: +1
next unless child.is_a?(Node) # unless: +1
yield child if types.empty? || # if: +1, ||: +1
types.include?(child.type)
end
self
end # total: 6
Method sync_workers
has a Cognitive Complexity of 16 (exceeds 11 allowed). Consider refactoring. Open
def sync_workers
ws = find_current_or_starting
current = ws.collect(&:queue_name).sort
desired = has_required_role? ? desired_queue_names.sort : []
result = {:adds => [], :deletes => []}
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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 count
instead of find_all...length
. Open
dups = current.uniq.find_all { |u| current.find_all { |c| c == u }.length > 1 }
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This cop is used to identify usages of count
on an Enumerable
that
follow calls to select
or reject
. Querying logic can instead be
passed to the count
call.
Example:
# bad
[1, 2, 3].select { |e| e > 2 }.size
[1, 2, 3].reject { |e| e > 2 }.size
[1, 2, 3].select { |e| e > 2 }.length
[1, 2, 3].reject { |e| e > 2 }.length
[1, 2, 3].select { |e| e > 2 }.count { |e| e.odd? }
[1, 2, 3].reject { |e| e > 2 }.count { |e| e.even? }
array.select(&:value).count
# good
[1, 2, 3].count { |e| e > 2 }
[1, 2, 3].count { |e| e < 2 }
[1, 2, 3].count { |e| e > 2 && e.odd? }
[1, 2, 3].count { |e| e < 2 && e.even? }
Model.select('field AS field_one').count
Model.select(:value).count
ActiveRecord
compatibility:
ActiveRecord
will ignore the block that is passed to count
.
Other methods, such as select
, will convert the association to an
array and then run the block on the array. A simple work around to
make count
work with a block is to call to_a.count {...}
.
Example: Model.where(id: [1, 2, 3].select { |m| m.method == true }.size
becomes:
Model.where(id: [1, 2, 3]).to_a.count { |m| m.method == true }