[Next Major] prevent autopagination from mutating

src/Stripe.net/Services/_base/BaseOptions.cs

@@ -19,6 +19,11 @@ public class BaseOptions : INestedOptions
         public IDictionary<string, object> ExtraParams { get; set; }
             = new Dictionary<string, object>();
 
+        internal BaseOptions Clone()
+        {
+            return (BaseOptions)this.MemberwiseClone();
+        }
+
         /// <summary>
         /// Adds an <c>expand</c> value to the request, to request expansion of a specific
         /// field in the response. When requesting expansions in a list request, don't forget

src/Stripe.net/Services/_base/Service.cs

@@ -327,7 +327,7 @@ protected IEnumerable<T> ListRequestAutoPagingSync<T>(
                 options,
                 requestOptions);
 
-            options = options ?? new ListOptions();
+            options = ((ListOptions)options?.Clone()) ?? new ListOptions();
             bool iterateBackward = false;
 
             // Backward iterating activates if we have an `EndingBefore`
@@ -397,7 +397,7 @@ protected async IAsyncEnumerable<T> ListRequestAutoPagingAsync<T>(
                 requestOptions,
                 cancellationToken);
 
-            options = options ?? new ListOptions();
+            options = ((ListOptions)options?.Clone()) ?? new ListOptions();
             bool iterateBackward = false;
 
             // Backward iterating activates if we have an `EndingBefore`
@@ -485,7 +485,7 @@ private IEnumerable<T> SearchRequestAutoPagingSync<T>(
                 options,
                 requestOptions);
 
-            options = options ?? new SearchOptions();
+            options = ((SearchOptions)options?.Clone()) ?? new SearchOptions();
 
             while (true)
             {
@@ -533,7 +533,7 @@ protected async IAsyncEnumerable<T> SearchRequestAutoPagingAsync<T>(
                 requestOptions,
                 cancellationToken);
 
-            options = options ?? new SearchOptions();
+            options = ((SearchOptions)options?.Clone()) ?? new SearchOptions();
 
             while (true)
             {

src/StripeTests/Services/AutoPagingTest.cs

@@ -193,6 +193,9 @@ public void ListAutoPaging_StartingAfter()
             Assert.Equal("pm_126", models[1].Id);
             Assert.Equal("pm_127", models[2].Id);
 
+            // Should not mutate its argument
+            Assert.Equal("pm_124", options.StartingAfter);
+
             // Check invocations
             this.MockHttpClientFixture.MockHandler.Protected()
                 .Verify(
@@ -247,6 +250,9 @@ public void ListAutoPaging_EndingBefore()
             };
             var models = service.ListAutoPaging(options).ToList();
 
+            // Should not mutate its argument
+            Assert.Equal("pm_127", options.EndingBefore);
+
             // Check results
             Assert.Equal(5, models.Count);
             Assert.Equal("pm_126", models[0].Id);

src/StripeTests/Services/_base/ServiceTest.cs

@@ -87,14 +87,17 @@ public void SearchAuto_ReturnsAllPages()
                 "?page=page2&query=my+query");
 
             var service = new TestService(this.StripeClient);
+            var options = new SearchOptions() { Query = "my query" };
 
             HashSet<string> ids = new HashSet<string>();
-            foreach (var testEntity in service.SearchAutoPaging(new SearchOptions() { Query = "my query" }))
+            foreach (var testEntity in service.SearchAutoPaging(options))
             {
                 Assert.NotNull(testEntity);
                 ids.Add(testEntity.Id);
             }
 
+            Assert.Null(options.Page);
+
             Assert.Equal(4, ids.Count);
             Assert.Equal(4, ids.Count);
         }
@@ -118,13 +121,16 @@ public async Task SearchAutoAsync_ReturnsAllPages()
 
             var service = new TestService(this.StripeClient);
 
+            var options = new SearchOptions() { Query = "my query" };
             HashSet<string> ids = new HashSet<string>();
-            await foreach (var testEntity in service.SearchAutoPagingAsync(new SearchOptions() { Query = "my query" }))
+            await foreach (var testEntity in service.SearchAutoPagingAsync(options))
             {
                 Assert.NotNull(testEntity);
                 ids.Add(testEntity.Id);
             }
 
+            Assert.Null(options.Page);
+
             Assert.Equal(4, ids.Count);
         }