Merge query parameters coming from path with params argument

.rubocop_todo.yml

@@ -8,17 +8,17 @@
 
 # Offense count: 19
 Metrics/AbcSize:
-  Max: 45
+  Max: 52
 
 # Offense count: 27
 # Configuration parameters: CountComments, ExcludedMethods.
 Metrics/BlockLength:
-  Max: 469
+  Max: 496
 
 # Offense count: 8
 # Configuration parameters: CountComments.
 Metrics/ClassLength:
-  Max: 597
+  Max: 624
 
 # Offense count: 11
 Metrics/CyclomaticComplexity:
@@ -33,7 +33,7 @@ Metrics/LineLength:
 # Offense count: 32
 # Configuration parameters: CountComments.
 Metrics/MethodLength:
-  Max: 46
+  Max: 48
 
 # Offense count: 1
 # Configuration parameters: CountComments.

lib/stripe/stripe_client.rb

@@ -134,6 +134,23 @@ def execute_request(method, path,
                end
       end
 
+      # This works around an edge case where we end up with both query
+      # parameters in `query_params` and query parameters that are appended
+      # onto the end of the given path. In this case, Faraday will silently
+      # discard the URL's parameters which may break a request.
+      #
+      # Here we decode any parameters that were added onto the end of a path
+      # and add them to `query_params` so that all parameters end up in one
+      # place and all of them are correctly included in the final request.
+      u = URI.parse(path)
+      unless u.query.nil?
+        query_params ||= {}
+        query_params = Hash[URI.decode_www_form(u.query)].merge(query_params)
+
+        # Reset the path minus any query parameters that were specified.
+        path = u.path
+      end
+
       headers = request_headers(api_key, method)
                 .update(Util.normalize_headers(headers))
 

test/stripe/stripe_client_test.rb

@@ -681,6 +681,35 @@ class StripeClientTest < Test::Unit::TestCase
             }
           )
         end
+
+        should "merge query parameters in URL and params" do
+          client = StripeClient.new
+          client.execute_request(:get, "/v1/invoices/upcoming?coupon=25OFF", params: {
+            customer: "cus_123",
+          })
+          assert_requested(
+            :get,
+            "#{Stripe.api_base}/v1/invoices/upcoming?",
+            query: {
+              coupon: "25OFF",
+              customer: "cus_123",
+            }
+          )
+        end
+
+        should "prefer query parameters in params when specified in URL as well" do
+          client = StripeClient.new
+          client.execute_request(:get, "/v1/invoices/upcoming?customer=cus_query", params: {
+            customer: "cus_param",
+          })
+          assert_requested(
+            :get,
+            "#{Stripe.api_base}/v1/invoices/upcoming?",
+            query: {
+              customer: "cus_param",
+            }
+          )
+        end
       end
     end