Merge pull request #682 from presidentbeef/make_array_new_into_an_array

Make Array.new into an array and Hash.new into a hash

lib/brakeman/processors/alias_processor.rb

@@ -74,6 +74,9 @@ class Brakeman::AliasProcessor < Brakeman::SexpProcessor
     result
   end
 
+  ARRAY_CONST = s(:const, :Array)
+  HASH_CONST = s(:const, :Hash)
+
   #Process a method call.
   def process_call exp
     target_var = exp.target
@@ -96,6 +99,10 @@ class Brakeman::AliasProcessor < Brakeman::SexpProcessor
     if node_type? target, :or and [:+, :-, :*, :/].include? method
       res = process_or_simple_operation(exp)
       return res if res
+    elsif target == ARRAY_CONST and method == :new
+      return Sexp.new(:array, *exp.args)
+    elsif target == HASH_CONST and method == :new and first_arg.nil? and !node_type?(@exp_context.last, :iter, :call_with_block)
+      return Sexp.new(:hash)
     end
 
     #See if it is possible to simplify some basic cases
@@ -187,7 +194,9 @@ class Brakeman::AliasProcessor < Brakeman::SexpProcessor
   end
 
   def process_call_with_block exp
+    @exp_context.push exp
     exp[1] = process exp.block_call
+    @exp_context.pop
 
     env.scope do
       exp.block_args.each do |e|

test/tests/alias_processor.rb

@@ -108,6 +108,22 @@ class AliasProcessorTests < Test::Unit::TestCase
     RUBY
   end
 
+  def test_array_new_append
+    assert_alias '[1, 2, 3]', <<-RUBY
+      x = Array.new
+      x << 1 << 2 << 3
+      x
+    RUBY
+  end
+
+  def test_array_new_init_append
+    assert_alias '[1, 2, 3]', <<-RUBY
+      x = Array.new(1)
+      x << 2 << 3
+      x
+    RUBY
+  end
+
   def test_hash_index
     assert_alias "'You say goodbye, I say :hello'", <<-RUBY
       x = {:goodbye => "goodbye cruel world" }
@@ -117,6 +133,15 @@ class AliasProcessorTests < Test::Unit::TestCase
     RUBY
   end
 
+  def test_hash_new_index
+    assert_alias "'You say goodbye, I say :hello'", <<-RUBY
+      x = Hash.new
+      x[:hello] = "hello world"
+      x.merge! :goodbye => "You say goodbye, I say :hello"
+      x[:goodbye]
+    RUBY
+  end
+
   def test_obvious_if
     assert_alias "'Yes!'", <<-RUBY
       condition = true