Always dup url_prefix in Connection#build_exclusive_url (#1288)

Author: alexeyds

lib/faraday/connection.rb

@@ -520,9 +520,8 @@ def build_request(method)
     # @return [URI]
     def build_exclusive_url(url = nil, params = nil, params_encoder = nil)
       url = nil if url.respond_to?(:empty?) && url.empty?
-      base = url_prefix
+      base = url_prefix.dup
       if url && base.path && base.path !~ %r{/$}
-        base = base.dup
         base.path = "#{base.path}/" # ensure trailing slash
       end
       url = url && URI.parse(url.to_s).opaque ? url.to_s.gsub(':', '%3A') : url

spec/faraday/connection_spec.rb

@@ -253,6 +253,13 @@
       expect(uri.path).to eq('/sake.html')
     end
 
+    it 'always returns new URI instance' do
+      conn.url_prefix = 'http://sushi.com'
+      uri1 = conn.build_exclusive_url(nil)
+      uri2 = conn.build_exclusive_url(nil)
+      expect(uri1).not_to equal(uri2)
+    end
+
     context 'with url_prefixed connection' do
       let(:url) { 'http://sushi.com/sushi/' }