Merge pull request #478 from jrafanie/dup_names_hash_when_copying_header_hash

Dup the @names hash when the Headers hash is copied.

lib/faraday/utils.rb

@@ -17,6 +17,12 @@ module Faraday
         self.update(hash || {})
       end
 
+      # on dup/clone, we need to duplicate @names hash
+      def initialize_copy(other)
+        super
+        @names = other.names.dup
+      end
+
       # need to synchronize concurrent writes to the shared KeyMap
       keymap_mutex = Mutex.new
 
@@ -102,6 +108,12 @@ module Faraday
             end
           }
       end
+
+      protected
+
+      def names
+        @names
+      end
     end
 
     # hash with stringified keys

test/connection_test.rb

@@ -200,6 +200,20 @@ class TestConnection < Faraday::TestCase
     assert_equal "http://sushi.com/nigiri?a=1&b=2&c=3", url.to_s
   end
 
+  def test_request_header_change_does_not_modify_connection_header
+    connection = Faraday.new(:url => "https://asushi.com/sake.html")
+    connection.headers = { "Authorization"=>"token abc123" }
+
+    request = connection.build_request(:get)
+    request.headers.delete("Authorization")
+
+    assert_equal connection.headers.keys.sort, ["Authorization"]
+    assert connection.headers.include?("Authorization")
+
+    assert_equal request.headers.keys.sort, []
+    assert !request.headers.include?("Authorization")
+  end
+
   def test_env_url_parses_url_params_into_query
     uri = env_url("http://sushi.com/sake.html", 'a[b]' => '1 + 2')
     assert_equal "a%5Bb%5D=1+%2B+2", uri.query