Tighten use of form-encoding to only cases where a JSON body is not ever allowed

lib/google/apis/core/api_command.rb

@@ -105,6 +105,10 @@ module Google
           end
         end
 
+        def allow_form_encoding?
+          request_representation.nil? && super
+        end
+
         private
 
         # Attempt to parse a JSON error message, returning the first found error

lib/google/apis/core/http_command.rb

@@ -146,7 +146,7 @@ module Google
           self.url = url.expand(params) if url.is_a?(Addressable::Template)
           url.query_values = query.merge(url.query_values || {})
 
-          if [:post, :put].include?(method)  && body.nil?
+          if allow_form_encoding?
             @form_encoded = true
             self.body = Addressable::URI.form_encode(url.query_values(Array))
             self.header['Content-Type'] = 'application/x-www-form-urlencoded; charset=UTF-8'
@@ -306,6 +306,10 @@ module Google
           req.options.open_timeout = options.open_timeout_sec
         end
 
+        def allow_form_encoding?
+          [:post, :put].include?(method) && body.nil?
+        end
+
         private
 
         def form_encoded?

spec/google/apis/core/api_command_spec.rb

@@ -17,7 +17,7 @@ require 'google/apis/core/api_command'
 require 'google/apis/core/json_representation'
 require 'hurley/test'
 
-RSpec.describe Google::Apis::Core::HttpCommand do
+RSpec.describe Google::Apis::Core::ApiCommand do
   include TestHelpers
   include_context 'HTTP client'
 
@@ -40,20 +40,28 @@ RSpec.describe Google::Apis::Core::HttpCommand do
       command = Google::Apis::Core::ApiCommand.new(:post, 'https://www.googleapis.com/zoo/animals')
       command.request_representation = representer_class
       command.request_object = request
+      command.query['a'] = 'b'
       command
     end
 
     before(:example) do
-      stub_request(:post, 'https://www.googleapis.com/zoo/animals')
+      stub_request(:post, 'https://www.googleapis.com/zoo/animals?a=b')
         .to_return(headers: { 'Content-Type' => 'application/json' }, body: %({}))
     end
 
     it 'should serialize the request object' do
       command.execute(client)
-      expect(a_request(:post, 'https://www.googleapis.com/zoo/animals').with do |req|
+      expect(a_request(:post, 'https://www.googleapis.com/zoo/animals?a=b').with do |req|
         be_json_eql(%({"value":"hello"})).matches?(req.body)
       end).to have_been_made
     end
+
+    it 'should not form encode query parameters when body expected but nil' do
+      command.query['a'] = 'b'
+      command.request_object = nil
+      command.execute(client)
+      expect(a_request(:post, 'https://www.googleapis.com/zoo/animals?a=b').with(body: nil)).to have_been_made
+    end
   end
 
   context('with a JSON response') do