[Fix rubocop#3578] Fix safe navigation counting in Metrics/AbcSize

This cop wasn't correctly counting method calls that happen with the safe navigation operator (`x&.y`), it has been changed so that they are treated the same as other method calls (like `x.y`).

Adds a test which checks the score of a method with the safe navigation operator. The test would fail without the change in the cop.

CHANGELOG.md

@@ -27,6 +27,7 @@
 * [#3334](https://github.com/bbatsov/rubocop/issues/3334): Do not register an offense for a literal space (`\s`) in `Style/UnneededCapitalW`. ([@rrosenblum][])
 * [#3390](https://github.com/bbatsov/rubocop/issues/3390): Fix SaveBang cop for multiple conditional. ([@tejasbubane][])
 * [#3577](https://github.com/bbatsov/rubocop/issues/3577): Fix `Style/RaiseArgs` not allowing compact raise with splatted args. ([@savef][])
+* [#3578](https://github.com/bbatsov/rubocop/issues/3578): Fix safe navigation method call counting in `Metrics/AbcSize`. ([@savef][])
 
 ### Changes
 

lib/rubocop/cop/metrics/abc_size.rb

@@ -11,7 +11,7 @@ class AbcSize < Cop
 
         MSG = 'Assignment Branch Condition size for %s is too high. ' \
               '[%.4g/%.4g]'.freeze
-        BRANCH_NODES = [:send].freeze
+        BRANCH_NODES = [:send, :csend].freeze
         CONDITION_NODES = CyclomaticComplexity::COUNTED_NODES.freeze
 
         private

spec/rubocop/cop/metrics/abc_size_spec.rb

@@ -57,7 +57,19 @@
                       'end'])
       expect(cop.messages)
         .to eq(['Assignment Branch Condition size for method_name is too ' \
-                'high. [6.4/0]']) # square root of 1*1 + 5*5 + 2*2 => 6.4
+                'high. [6.4/0]']) # sqrt(1*1 + 5*5 + 2*2) => 6.4
+    end
+
+    context 'target_ruby_version >= 2.3', :ruby23 do
+      it 'treats safe navigation method calls like regular method calls' do
+        inspect_source(cop,
+                       ['def method_name',
+                        '  object&.do_something',
+                        'end'])
+        expect(cop.messages)
+          .to eq(['Assignment Branch Condition size for method_name is too ' \
+                  'high. [2/0]']) # sqrt(0 + 2*2 + 0) => 2
+      end
     end
   end