Respond to CR.

// FREEBIE

Signal/src/AppDelegate.m

@@ -523,7 +523,7 @@ static NSString *const kURLHostVerifyPrefix             = @"verify";
         // Avoid blocking app launch by putting all further possible DB access in async block
         dispatch_async(dispatch_get_main_queue(), ^{
             [TSSocketManager requestSocketOpen];
-            [[Environment getCurrent].contactsManager fetchSystemContactsIfAlreadyAuthorized];
+            [[Environment getCurrent].contactsManager fetchSystemContactsOnceIfAlreadyAuthorized];
             // This will fetch new messages, if we're using domain fronting.
             [[PushManager sharedManager] applicationDidBecomeActive];
 

Signal/src/contact/OWSContactsManager.h

@@ -71,7 +71,9 @@ extern NSString *const OWSContactsManagerSignalAccountsDidChangeNotification;
 
 // Ensure's the app has the latest contacts, but won't prompt the user for contact
 // access if they haven't granted it.
-- (void)fetchSystemContactsIfAlreadyAuthorized;
+- (void)fetchSystemContactsOnceIfAlreadyAuthorized;
+// This variant will fetch system contacts if contact access has already been granted,
+// but not prompt for contact access. Also, it will always fire a notification.
 - (void)fetchSystemContactsIfAlreadyAuthorizedAndAlwaysNotify;
 
 #pragma mark - Util

Signal/src/contact/OWSContactsManager.m

@@ -93,14 +93,14 @@ NSString *const kTSStorageManager_lastKnownContactRecipientIds = @"lastKnownCont
     [self.systemContactsFetcher requestOnceWithCompletion:completion];
 }
 
-- (void)fetchSystemContactsIfAlreadyAuthorized
+- (void)fetchSystemContactsOnceIfAlreadyAuthorized
 {
-    [self.systemContactsFetcher fetchIfAlreadyAuthorizedWithAlwaysNotify:NO];
+    [self.systemContactsFetcher fetchOnceIfAlreadyAuthorized];
 }
 
 - (void)fetchSystemContactsIfAlreadyAuthorizedAndAlwaysNotify
 {
-    [self.systemContactsFetcher fetchIfAlreadyAuthorizedWithAlwaysNotify:YES];
+    [self.systemContactsFetcher fetchIfAlreadyAuthorizedAndAlwaysNotify];
 }
 
 - (BOOL)isSystemContactsAuthorized

Signal/src/contact/SystemContactsFetcher.swift

@@ -344,7 +344,6 @@ class SystemContactsFetcher: NSObject {
 
     private var systemContactsHaveBeenRequestedAtLeastOnce = false
     private var hasSetupObservation = false
-    private var isFetchingContacts = false
 
     override init() {
         self.contactStoreAdapter = ContactStoreAdapter()
@@ -362,8 +361,7 @@ class SystemContactsFetcher: NSObject {
         hasSetupObservation = true
         self.contactStoreAdapter.startObservingChanges { [weak self] in
             DispatchQueue.main.async {
-                // If contacts have changed, don't de-bounce.
-                self?.updateContacts(completion: nil, alwaysNotify: false, shouldDebounce: false)
+                self?.updateContacts(completion: nil, alwaysNotify: false)
             }
         }
     }
@@ -382,7 +380,6 @@ class SystemContactsFetcher: NSObject {
             completion?(nil)
             return
         }
-        systemContactsHaveBeenRequestedAtLeastOnce = true
         setupObservationIfNecessary()
 
         switch authorizationStatus {
@@ -419,33 +416,28 @@ class SystemContactsFetcher: NSObject {
         }
     }
 
-    public func fetchIfAlreadyAuthorized(alwaysNotify: Bool = false) {
+    public func fetchOnceIfAlreadyAuthorized() {
         AssertIsOnMainThread()
         guard authorizationStatus == .authorized else {
             return
         }
-
-        updateContacts(completion: nil, alwaysNotify:alwaysNotify)
+        guard !systemContactsHaveBeenRequestedAtLeastOnce else {
+            return
         }
 
-    private func tryToAcquireContactFetchLock() -> Bool {
-        var didAcquireLock = false
-        objc_sync_enter(self)
-        if !self.isFetchingContacts {
-            self.isFetchingContacts = true
-            didAcquireLock = true
+        updateContacts(completion: nil, alwaysNotify:false)
     }
-        objc_sync_exit(self)
-        return didAcquireLock
+
+    public func fetchIfAlreadyAuthorizedAndAlwaysNotify() {
+        AssertIsOnMainThread()
+        guard authorizationStatus == .authorized else {
+            return
         }
 
-    private func releaseContactFetchLock() {
-        objc_sync_enter(self)
-        self.isFetchingContacts = false
-        objc_sync_exit(self)
+        updateContacts(completion: nil, alwaysNotify:true)
     }
 
-    private func updateContacts(completion: ((Error?) -> Void)?, alwaysNotify: Bool = false, shouldDebounce: Bool = true) {
+    private func updateContacts(completion: ((Error?) -> Void)?, alwaysNotify: Bool = false) {
         AssertIsOnMainThread()
 
         systemContactsHaveBeenRequestedAtLeastOnce = true
@@ -453,18 +445,6 @@ class SystemContactsFetcher: NSObject {
 
         DispatchQueue.global().async {
 
-            if shouldDebounce {
-                guard self.tryToAcquireContactFetchLock() else {
-                    Logger.info("\(self.TAG) ignoring redundant system contacts fetch.")
-                    return
-                }
-            }
-            defer {
-                if shouldDebounce {
-                    self.releaseContactFetchLock()
-                }
-            }
-
             Logger.info("\(self.TAG) fetching contacts")
 
             var fetchedContacts: [Contact]?