New cop Style/Send checks for the use of send (disabled by default)

CHANGELOG.md

@@ -4,6 +4,7 @@
 
 ### New features
 
+* [#2081](https://github.com/bbatsov/rubocop/pull/2081): New cop `Style/Send` checks for the use of `send` and instead encourages changing it to `BasicObject#__send__` or `Object#public_send` (disabled by default). ([@syndbg][])
 * [#2057](https://github.com/bbatsov/rubocop/pull/2057): New cop `Lint/FormatParameterMismatch` checks for a mismatch between the number of fields expected in format/sprintf/% and what was pased to it. ([@edmz][])
 * [#2010](https://github.com/bbatsov/rubocop/pull/2010): Add `space` style for SpaceInsideStringInterpolation. ([@gotrevor][])
 * [#2007](https://github.com/bbatsov/rubocop/pull/2007): Allow any modifier before `def`, not only visibility modifiers. ([@fphilipe][])
@@ -1521,3 +1522,4 @@
 [@maxjacobson]: https://github.com/maxjacobson
 [@sliuu]: https://github.com/sliuu
 [@edmz]: https://github.com/edmz
+[@syndbg]: https://github.com/syndbg

config/disabled.yml

@@ -46,6 +46,10 @@ Style/MissingElse:
 
 Style/OptionHash:
   Description: "Don't use option hashes when you can use keyword arguments."
+
+Style/Send:
+  Description: 'Prefer `Object#__send__` or `Object#public_send` to `send`, as `send` may overlap with existing methods.'
+  StyleGuide: 'https://github.com/bbatsov/ruby-style-guide#prefer-public-send'
   Enabled: false
 
 Style/SymbolArray:

lib/rubocop.rb

@@ -247,6 +247,7 @@
 require 'rubocop/cop/style/rescue_modifier'
 require 'rubocop/cop/style/self_assignment'
 require 'rubocop/cop/style/semicolon'
+require 'rubocop/cop/style/send'
 require 'rubocop/cop/style/signal_exception'
 require 'rubocop/cop/style/single_line_block_params'
 require 'rubocop/cop/style/single_line_methods'

lib/rubocop/cop/style/send.rb

@@ -0,0 +1,18 @@
+# encoding: utf-8
+
+module RuboCop
+  module Cop
+    module Style
+      # This cop checks for the use of the send method.
+      class Send < Cop
+        MSG = 'Prefer `Object#__send__` or `Object#public_send` to `send`.'
+
+        def on_send(node)
+          _receiver, method_name, *args = *node
+          return unless method_name == :send && args.length > 0
+          add_offense(node, :selector)
+        end
+      end
+    end
+  end
+end

spec/rubocop/cop/style/send_spec.rb

@@ -0,0 +1,81 @@
+# encoding: utf-8
+
+require 'spec_helper'
+
+describe RuboCop::Cop::Style::Send do
+  subject(:cop) { described_class.new }
+
+  context 'with send' do
+    context 'and with a receiver' do
+      it 'registers an offense for an invocation with args' do
+        inspect_source(cop, 'Object.send(:inspect)')
+        expect(cop.offenses.size).to eq(1)
+      end
+
+      it 'does not register an offense for an invocation without args' do
+        inspect_source(cop, 'Object.send')
+        expect(cop.offenses).to be_empty
+      end
+    end
+
+    context 'and without a receiver' do
+      it 'registers an offense for an invocation with args' do
+        inspect_source(cop, 'send(:inspect)')
+        expect(cop.offenses.size).to eq(1)
+      end
+
+      it 'does not register an offense for an invocation without args' do
+        inspect_source(cop, 'send')
+        expect(cop.offenses).to be_empty
+      end
+    end
+  end
+
+  context 'with __send__' do
+    after(:each) { expect(cop.offenses).to be_empty }
+
+    context 'and with a receiver' do
+      it 'does not register an offense for an invocation with args' do
+        inspect_source(cop, 'Object.__send__(:inspect)')
+      end
+
+      it 'does not register an offense for an invocation without args' do
+        inspect_source(cop, 'Object.__send__')
+      end
+    end
+
+    context 'and without a receiver' do
+      it 'does not register an offense for an invocation with args' do
+        inspect_source(cop, '__send__(:inspect)')
+      end
+
+      it 'does not register an offense for an invocation without args' do
+        inspect_source(cop, '__send__')
+      end
+    end
+  end
+
+  context 'with public_send' do
+    after(:each) { expect(cop.offenses).to be_empty }
+
+    context 'and with a receiver' do
+      it 'does not register an offense for an invocation with args' do
+        inspect_source(cop, 'Object.public_send(:inspect)')
+      end
+
+      it 'does not register an offense for an invocation without args' do
+        inspect_source(cop, 'Object.public_send')
+      end
+    end
+
+    context 'and without a receiver' do
+      it 'does not register an offense for an invocation with args' do
+        inspect_source(cop, 'public_send(:inspect)')
+      end
+
+      it 'does not register an offense for an invocation without args' do
+        inspect_source(cop, 'public_send')
+      end
+    end
+  end
+end