Fix for INTENG-21262

-> Remove archived request file from disk when those req. are added in queue for processing on app launch.
-> When persist timer is fired and req queue is empty, delete cache file from disk. persistImmediately func was earlier returning without updating cache if req queue was empty.
-> Added check fileExistsAtPath before removing it in func removeSaveFile.

Branch-TestBed/Branch-SDK-Tests/BNCServerRequestQueueTests.m

@@ -25,6 +25,8 @@ - (id)unarchiveObjectFromData:(NSData *)data;
 // returns data in the legacy format
 - (NSData *)oldArchiveQueue:(NSArray<BNCServerRequest *> *)queue;
 
++ (NSURL * _Nonnull) URLForQueueFile;
+
 @end
 
 @interface BNCServerRequestQueueTests : XCTestCase
@@ -157,4 +159,26 @@ - (void)testOldArchiveArrayOfInvalidObjects {
     XCTAssert(unarchived.count == 2);
 }
 
+- (void)testMultipleRequests {
+    BranchEventRequest *eventObject = [BranchEventRequest new];
+    BranchOpenRequest *openObject = [BranchOpenRequest new];
+
+    [_queue enqueue: eventObject];
+    [_queue enqueue: openObject];
+    [_queue persistImmediately];
+
+    NSMutableArray *decodedQueue = nil;
+    NSData *data = [NSData dataWithContentsOfURL:[BNCServerRequestQueue URLForQueueFile] options:0 error:nil];
+    if (data) {
+        decodedQueue = [_queue unarchiveQueueFromData:data];
+    }
+    XCTAssert([decodedQueue count] == 2);
+
+    [_queue remove:eventObject];
+    [_queue remove:openObject];
+    [_queue persistImmediately];
+     // Request Queue is empty. So there should not be any queue file on disk.
+    XCTAssert([NSFileManager.defaultManager fileExistsAtPath:[[BNCServerRequestQueue URLForQueueFile] path]] == NO);
+}
+
 @end

Sources/BranchSDK/BNCServerRequestQueue.m

@@ -217,6 +217,8 @@ - (void)cancelTimer {
 - (void)persistImmediately {
     @synchronized (self) {
         if (!self.queue || self.queue.count == 0) {
+            //No more requests. Delete cached queue file.
+            [self removeSaveFile];
             return;
         }
         NSArray *queueCopy = [self.queue copy];
@@ -287,14 +289,16 @@ - (void)retrieve {
                 }
             }
             self.queue = decodedQueue;
+            // Requests are loaded into queue now. Delete queue file stored on disk.
+            [self removeSaveFile];
         }
     }
 }
 
 // It's been reported that unarchive can fail in some situations. In that case, remove the queued requests file.
 - (void)removeSaveFile {
     NSURL *fileURL = [BNCServerRequestQueue URLForQueueFile];
-    if (fileURL) {
+    if (fileURL && [NSFileManager.defaultManager fileExistsAtPath:[fileURL path]]) {
         NSError *error;
         [NSFileManager.defaultManager removeItemAtURL:fileURL error:&error];