New items to history are dropped if history_size is zero

Author: aycabta

lib/reline/history.rb

@@ -29,6 +29,8 @@ def concat(*val)
   end
 
   def push(*val)
+    # If history_size is zero, all histories are dropped.
+    return self if @config.history_size.zero?
     diff = size + val.size - @config.history_size
     if diff > 0
       if diff <= size
@@ -43,6 +45,8 @@ def push(*val)
   end
 
   def <<(val)
+    # If history_size is zero, all histories are dropped.
+    return self if @config.history_size.zero?
     shift if size + 1 > @config.history_size
     super(String.new(val, encoding: Reline.encoding_system_needs))
   end

test/reline/test_history.rb

@@ -242,6 +242,16 @@ def test_delete_at__out_of_range
     end
   end
 
+  def test_history_size_zero
+    history = history_new(history_size: 0)
+    assert_equal 0, history.size
+    history << 'aa'
+    history << 'bb'
+    assert_equal 0, history.size
+    history.push(*%w{aa bb cc})
+    assert_equal 0, history.size
+  end
+
   private
 
   def history_new(history_size: 10)