Resolve "Make a Rubocop that forbids returning from a block"

2 files changed, 201 insertions, 0 deletions

diff --git a/spec/rubocop/cop/avoid_break_from_strong_memoize_spec.rb b/spec/rubocop/cop/avoid_break_from_strong_memoize_spec.rb
new file mode 100644
index 00000000000..ac7b1575ec0
--- /dev/null
+++ b/spec/rubocop/cop/avoid_break_from_strong_memoize_spec.rb
@@ -0,0 +1,74 @@
+require 'spec_helper'
+require 'rubocop'
+require 'rubocop/rspec/support'
+require_relative '../../../rubocop/cop/avoid_break_from_strong_memoize'
+
+describe RuboCop::Cop::AvoidBreakFromStrongMemoize do
+  include CopHelper
+
+  subject(:cop) { described_class.new }
+
+  it 'flags violation for break inside strong_memoize' do
+    expect_offense(<<~RUBY)
+      strong_memoize(:result) do
+        break if something
+        ^^^^^ Do not use break inside strong_memoize, use next instead.
+
+        do_an_heavy_calculation
+      end
+    RUBY
+  end
+
+  it 'flags violation for break inside strong_memoize nested blocks' do
+    expect_offense(<<~RUBY)
+      strong_memoize do
+        items.each do |item|
+          break item
+          ^^^^^^^^^^ Do not use break inside strong_memoize, use next instead.
+        end
+      end
+    RUBY
+  end
+
+  it "doesn't flag violation for next inside strong_memoize" do
+    expect_no_offenses(<<~RUBY)
+      strong_memoize(:result) do
+        next if something
+
+        do_an_heavy_calculation
+      end
+    RUBY
+  end
+
+  it "doesn't flag violation for break inside blocks" do
+    expect_no_offenses(<<~RUBY)
+      call do
+        break if something
+
+        do_an_heavy_calculation
+      end
+    RUBY
+  end
+
+  it "doesn't call add_offense twice for nested blocks" do
+    source = <<~RUBY
+      call do
+        strong_memoize(:result) do
+          break if something
+
+          do_an_heavy_calculation
+        end
+      end
+    RUBY
+    expect_any_instance_of(described_class).to receive(:add_offense).once
+
+    inspect_source(source)
+  end
+
+  it "doesn't check when block is empty" do
+    expect_no_offenses(<<~RUBY)
+      strong_memoize(:result) do
+      end
+    RUBY
+  end
+end
diff --git a/spec/rubocop/cop/avoid_return_from_blocks_spec.rb b/spec/rubocop/cop/avoid_return_from_blocks_spec.rb
new file mode 100644
index 00000000000..a5c280a7adc
--- /dev/null
+++ b/spec/rubocop/cop/avoid_return_from_blocks_spec.rb
@@ -0,0 +1,127 @@
+require 'spec_helper'
+require 'rubocop'
+require 'rubocop/rspec/support'
+require_relative '../../../rubocop/cop/avoid_return_from_blocks'
+
+describe RuboCop::Cop::AvoidReturnFromBlocks do
+  include CopHelper
+
+  subject(:cop) { described_class.new }
+
+  it 'flags violation for return inside a block' do
+    expect_offense(<<~RUBY)
+      call do
+        do_something
+        return if something_else
+        ^^^^^^ Do not return from a block, use next or break instead.
+      end
+    RUBY
+  end
+
+  it "doesn't call add_offense twice for nested blocks" do
+    source = <<~RUBY
+      call do
+        call do
+          something
+          return if something_else
+        end
+      end
+    RUBY
+    expect_any_instance_of(described_class).to receive(:add_offense).once
+
+    inspect_source(source)
+  end
+
+  it 'flags violation for return inside included > def > block' do
+    expect_offense(<<~RUBY)
+      included do
+        def a_method
+          return if something
+
+          call do
+            return if something_else
+            ^^^^^^ Do not return from a block, use next or break instead.
+          end
+        end
+      end
+    RUBY
+  end
+
+  shared_examples 'examples with whitelisted method' do |whitelisted_method|
+    it "doesn't flag violation for return inside #{whitelisted_method}" do
+      expect_no_offenses(<<~RUBY)
+        items.#{whitelisted_method} do |item|
+          do_something
+          return if something_else
+        end
+      RUBY
+    end
+  end
+
+  %i[each each_filename times loop].each do |whitelisted_method|
+    it_behaves_like 'examples with whitelisted method', whitelisted_method
+  end
+
+  shared_examples 'examples with def methods' do |def_method|
+    it "doesn't flag violation for return inside #{def_method}" do
+      expect_no_offenses(<<~RUBY)
+        helpers do
+          #{def_method} do
+            return if something
+
+            do_something_more
+          end
+        end
+      RUBY
+    end
+  end
+
+  %i[define_method lambda].each do |def_method|
+    it_behaves_like 'examples with def methods', def_method
+  end
+
+  it "doesn't flag violation for return inside a lambda" do
+    expect_no_offenses(<<~RUBY)
+      lambda do
+        do_something
+        return if something_else
+      end
+    RUBY
+  end
+
+  it "doesn't flag violation for return used inside a method definition" do
+    expect_no_offenses(<<~RUBY)
+      describe Klass do
+        def a_method
+          do_something
+          return if something_else
+        end
+      end
+    RUBY
+  end
+
+  it "doesn't flag violation for next inside a block" do
+    expect_no_offenses(<<~RUBY)
+      call do
+        do_something
+        next if something_else
+      end
+    RUBY
+  end
+
+  it "doesn't flag violation for break inside a block" do
+    expect_no_offenses(<<~RUBY)
+      call do
+        do_something
+        break if something_else
+      end
+    RUBY
+  end
+
+  it "doesn't check when block is empty" do
+    expect_no_offenses(<<~RUBY)
+      call do
+      end
+    RUBY
+  end
+end