Preserve completed Apple upload acknowledgements during cancellation

lib/http/HttpClient_Apple.mm

@@ -378,7 +378,11 @@ void HandleResponse(NSData* data, NSURLResponse* response, NSError* error)
                 }
             }
 
-            if (cancelRequested)
+            // A late cancellation must not discard an acknowledgement from a
+            // completed transfer. Status 200 alone is insufficient if it failed.
+            const bool completedSuccess = error == nil && httpResp != nil &&
+                                          simpleResponse->m_statusCode == 200 && !headersTooLarge;
+            if (cancelRequested && !completedSuccess)
             {
                 simpleResponse->m_result = HttpResult_Aborted;
             }
@@ -463,7 +467,11 @@ bool Cancel()
         return m_callback == nullptr && m_dataTask == nil;
     }
 
-private:
+   private:
+#if defined(MATSDK_APPLE_HTTP_TESTS)
+    friend MATSDK_LIBABI void CompleteAppleResponseForTest(IHttpResponseCallback*, bool, unsigned, int, size_t);
+#endif
+
     void Complete(HttpResult result)
     {
         IHttpResponseCallback* callback = nullptr;
@@ -517,6 +525,35 @@ void Complete(HttpResult result)
     bool m_terminal = false;
 };
 
+#if defined(MATSDK_APPLE_HTTP_TESTS)
+MATSDK_LIBABI void CompleteAppleResponseForTest(IHttpResponseCallback* callback,
+                                                bool cancelRequested,
+                                                unsigned statusCode,
+                                                int errorCode,
+                                                size_t headerSize)
+{
+    @autoreleasepool
+    {
+        HttpClient_Apple parent;
+        HttpRequestApple request(&parent);
+        request.m_callback = callback;
+        if (cancelRequested)
+        {
+            request.Cancel();
+        }
+        NSString* value = [@"" stringByPaddingToLength:headerSize withString:@"x" startingAtIndex:0];
+        NSURL* url = [NSURL URLWithString:@"https://localhost/"];
+        NSHTTPURLResponse* response = statusCode == 0 ? nil : [[NSHTTPURLResponse alloc] initWithURL:url
+                                                                                          statusCode:statusCode
+                                                                                         HTTPVersion:@"HTTP/1.1"
+                                                                                        headerFields:@{@"X-Test" : value}];
+        NSError* error = errorCode == 0 ? nil : [NSError errorWithDomain:NSURLErrorDomain code:errorCode userInfo:nil];
+        NSData* body = [@"{\"acc\":1}" dataUsingEncoding:NSUTF8StringEncoding];
+        request.HandleResponse(body, response, error);
+    }
+}
+#endif
+
 HttpClient_Apple::HttpClient_Apple()
 {
     LOG_TRACE("Initializing HttpClient_Apple...");

tests/unittests/CMakeLists.txt

@@ -1,5 +1,10 @@
 message(STATUS "Building unittests")
 
+if(APPLE AND PAL_IMPLEMENTATION STREQUAL "CPP11"
+    AND (MATSDK_BUILD_APPLE_HTTP OR MATSDK_PLATFORM_IOS))
+  target_compile_definitions(mat PRIVATE MATSDK_APPLE_HTTP_TESTS)
+endif()
+
 set(SRCS
   AIJsonSerializerTests.cpp
   AITelemetrySystemTests.cpp

tests/unittests/HttpClientTests.cpp

@@ -581,6 +581,67 @@ TEST_F(HttpClientTests, HandlesLocalErrors)
 }
 
 #if defined(MAT_TEST_APPLE_TRANSPORT)
+namespace MAT_NS_BEGIN
+{
+    void CompleteAppleResponseForTest(IHttpResponseCallback* callback,
+                                      bool cancelRequested,
+                                      unsigned statusCode,
+                                      int errorCode,
+                                      size_t headerSize);
+}
+MAT_NS_END
+
+TEST_F(HttpClientTests, CompletedAppleResponseSurvivesPendingCancellation)
+{
+    CompleteAppleResponseForTest(this, true, 200, 0, 4);
+
+    ASSERT_EQ(_responses.size(), 1u);
+    EXPECT_EQ(_responses[0]->GetResult(), HttpResult_OK);
+    EXPECT_EQ(_responses[0]->GetStatusCode(), 200u);
+    EXPECT_EQ(_responses[0]->GetHeaders().get("X-Test"), "xxxx");
+    const auto& body = _responses[0]->GetBody();
+    EXPECT_EQ(std::string(body.begin(), body.end()), "{\"acc\":1}");
+}
+
+TEST_F(HttpClientTests, PendingAppleCancellationDoesNotAcceptUnconfirmedResponses)
+{
+    struct ResponseCase
+    {
+        unsigned status;
+        int error;
+        size_t headerSize;
+    };
+    const ResponseCase cases[] = {
+        {200, -999, 4},   // NSURLErrorCancelled
+        {200, -1005, 4},  // NSURLErrorNetworkConnectionLost
+        {0, 0, 4},
+        {200, 0, MAX_HTTP_RESPONSE_HEADERS_SIZE},
+        {201, 0, 4},
+        {500, 0, 4},
+    };
+    for (const auto& test : cases)
+    {
+        SCOPED_TRACE(::testing::Message() << test.status << ", " << test.error << ", " << test.headerSize);
+        Clear();
+        CompleteAppleResponseForTest(this, true, test.status, test.error, test.headerSize);
+        ASSERT_EQ(_responses.size(), 1u);
+        EXPECT_EQ(_responses[0]->GetResult(), HttpResult_Aborted);
+        EXPECT_TRUE(_responses[0]->GetBody().empty());
+    }
+}
+
+TEST_F(HttpClientTests, AppleResponseValidationWithoutCancellationIsUnchanged)
+{
+    CompleteAppleResponseForTest(this, false, 200, 0, 4);
+    ASSERT_EQ(_responses.size(), 1u);
+    EXPECT_EQ(_responses[0]->GetResult(), HttpResult_OK);
+
+    Clear();
+    CompleteAppleResponseForTest(this, false, 200, 0, MAX_HTTP_RESPONSE_HEADERS_SIZE);
+    ASSERT_EQ(_responses.size(), 1u);
+    EXPECT_EQ(_responses[0]->GetResult(), HttpResult_NetworkFailure);
+}
+
 TEST_F(HttpClientTests, InvalidUtf8UrlCompletesExactlyOnce)
 {
     // The request must outlive the whole exchange: keep ownership here (the Apple