Fix the "is contact" test.

// FREEBIE

Signal/src/AppDelegate.m

@@ -837,6 +837,7 @@ static NSString *const kURLHostVerifyPrefix             = @"verify";
 
     [OWSProfileManager.sharedManager fetchLocalUsersProfile];
     [[OWSReadReceiptManager sharedManager] prepareCachedValues];
+    [[Environment getCurrent].contactsManager loadLastKnownContactRecipientIds];
 }
 
 - (void)registrationStateDidChange

Signal/src/ViewControllers/ConversationView/ConversationViewController.m

@@ -423,8 +423,8 @@ typedef NS_ENUM(NSInteger, MessagesRangeSizeMode) {
                                                  name:kNSNotificationName_ProfileWhitelistDidChange
                                                object:nil];
     [[NSNotificationCenter defaultCenter] addObserver:self
-                                             selector:@selector(contactsDidChange:)
+                                             selector:@selector(signalAccountsDidChange:)
-                                                 name:OWSContactsManagerContactListDidChangeNotification
+                                                 name:OWSContactsManagerSignalAccountsDidChangeNotification
                                                object:nil];
 }
 
@@ -446,7 +446,7 @@ typedef NS_ENUM(NSInteger, MessagesRangeSizeMode) {
     [[NSNotificationCenter defaultCenter] removeObserver:self name:UIKeyboardDidShowNotification object:nil];
 }
 
-- (void)contactsDidChange:(NSNotification *)notification
+- (void)signalAccountsDidChange:(NSNotification *)notification
 {
     OWSAssert([NSThread isMainThread]);
 

Signal/src/contact/OWSContactsManager.h

@@ -8,9 +8,6 @@
 NS_ASSUME_NONNULL_BEGIN
 
 extern NSString *const OWSContactsManagerSignalAccountsDidChangeNotification;
-// Fired when the list of contact phone numbers changes, not when
-// other contact properties change.
-extern NSString *const OWSContactsManagerContactListDidChangeNotification;
 
 @class ImageCache;
 @class SignalAccount;
@@ -39,10 +36,27 @@ extern NSString *const OWSContactsManagerContactListDidChangeNotification;
 @property (atomic, readonly) NSDictionary<NSString *, SignalAccount *> *signalAccountMap;
 @property (atomic, readonly) NSArray<SignalAccount *> *signalAccounts;
 
+// This value is cached and is available immediately, before system contacts
+// fetch or contacts intersection.
+//
+// In some cases, its better if our UI reflects these values
+// which haven't been updated yet rather than assume that
+// we have no contacts until the first contacts intersection
+// successfully completes.
+//
+// This significantly improves the user experience when:
+//
+// * No contacts intersection has completed because the app has just launched.
+// * Contacts intersection can't complete due to an unreliable connection or
+//   the contacts intersection rate limit.
+@property (atomic, readonly) NSArray<NSString *> *lastKnownContactRecipientIds;
+
 - (nullable SignalAccount *)signalAccountForRecipientId:(NSString *)recipientId;
 
 - (Contact *)getOrBuildContactForPhoneIdentifier:(NSString *)identifier;
 
+- (void)loadLastKnownContactRecipientIds;
+
 #pragma mark - System Contact Fetching
 
 // Must call `requestSystemContactsOnce` before accessing this method

Signal/src/contact/OWSContactsManager.m

@@ -16,14 +16,14 @@
 
 @import Contacts;
 
-NSString *const OWSContactsManagerSignalAccountsDidChangeNotification =
+NSString *const OWSContactsManagerSignalAccountsDidChangeNotification
-@"OWSContactsManagerSignalAccountsDidChangeNotification";
+    = @"OWSContactsManagerSignalAccountsDidChangeNotification";
-NSString *const OWSContactsManagerContactListDidChangeNotification =
-@"OWSContactsManagerContactListDidChangeNotification";
 
 NSString *const kTSStorageManager_AccountDisplayNames = @"kTSStorageManager_AccountDisplayNames";
 NSString *const kTSStorageManager_AccountFirstNames = @"kTSStorageManager_AccountFirstNames";
 NSString *const kTSStorageManager_AccountLastNames = @"kTSStorageManager_AccountLastNames";
+NSString *const kTSStorageManager_OWSContactsManager = @"kTSStorageManager_OWSContactsManager";
+NSString *const kTSStorageManager_lastKnownContactRecipientIds = @"lastKnownContactRecipientIds";
 
 @interface OWSContactsManager () <SystemContactsFetcherDelegate>
 
@@ -36,6 +36,7 @@ NSString *const kTSStorageManager_AccountLastNames = @"kTSStorageManager_Account
 @property (atomic) NSDictionary<NSString *, Contact *> *allContactsMap;
 @property (atomic) NSArray<SignalAccount *> *signalAccounts;
 @property (atomic) NSDictionary<NSString *, SignalAccount *> *signalAccountMap;
+@property (atomic) NSArray<NSString *> *lastKnownContactRecipientIds;
 @property (nonatomic, readonly) SystemContactsFetcher *systemContactsFetcher;
 
 @property (atomic) NSDictionary<NSString *, NSString *> *cachedAccountNameMap;
@@ -58,6 +59,7 @@ NSString *const kTSStorageManager_AccountLastNames = @"kTSStorageManager_Account
     _allContactsMap = @{};
     _signalAccountMap = @{};
     _signalAccounts = @[];
+    _lastKnownContactRecipientIds = @[];
     _systemContactsFetcher = [SystemContactsFetcher new];
     _systemContactsFetcher.delegate = self;
 
@@ -68,6 +70,18 @@ NSString *const kTSStorageManager_AccountLastNames = @"kTSStorageManager_Account
     return self;
 }
 
+- (void)loadLastKnownContactRecipientIds
+{
+    [TSStorageManager.sharedManager.newDatabaseConnection readWithBlock:^(
+        YapDatabaseReadTransaction *_Nonnull transaction) {
+        NSArray<NSString *> *_Nullable value = [transaction objectForKey:kTSStorageManager_lastKnownContactRecipientIds
+                                                            inCollection:kTSStorageManager_OWSContactsManager];
+        if (value) {
+            self.lastKnownContactRecipientIds = value;
+        }
+    }];
+}
+
 #pragma mark - System Contact Fetching
 
 // Request contacts access if you haven't asked recently.
@@ -178,8 +192,6 @@ NSString *const kTSStorageManager_AccountLastNames = @"kTSStorageManager_Account
         }
 
         dispatch_async(dispatch_get_main_queue(), ^{
-            BOOL didContactListChange = ![self.allContactsMap isEqual:allContactsMap];
-            
             self.allContacts = contacts;
             self.allContactsMap = [allContactsMap copy];
 
@@ -190,12 +202,6 @@ NSString *const kTSStorageManager_AccountLastNames = @"kTSStorageManager_Account
             [self updateSignalAccounts];
 
             [self updateCachedDisplayNames];
-            
-            if (didContactListChange) {
-                [[NSNotificationCenter defaultCenter]
-                 postNotificationNameAsync:OWSContactsManagerContactListDidChangeNotification
-                 object:nil];
-            }
         });
     });
 }
@@ -237,7 +243,16 @@ NSString *const kTSStorageManager_AccountLastNames = @"kTSStorageManager_Account
             }
         }
 
+        NSArray<NSString *> *lastKnownContactRecipientIds = [signalAccountMap allKeys];
+        [TSStorageManager.sharedManager.newDatabaseConnection
+            readWriteWithBlock:^(YapDatabaseReadWriteTransaction *_Nonnull transaction) {
+                [transaction setObject:lastKnownContactRecipientIds
+                                forKey:kTSStorageManager_lastKnownContactRecipientIds
+                          inCollection:kTSStorageManager_OWSContactsManager];
+            }];
+
         dispatch_async(dispatch_get_main_queue(), ^{
+            self.lastKnownContactRecipientIds = lastKnownContactRecipientIds;
             self.signalAccountMap = [signalAccountMap copy];
             self.signalAccounts = [signalAccounts copy];
 

Signal/src/util/ThreadUtil.m

@@ -385,7 +385,7 @@ NS_ASSUME_NONNULL_BEGIN
                     shouldHaveAddToProfileWhitelistOffer = NO;
                 }
 
-                BOOL isContact = contactsManager.allContactsMap[recipientId] != nil;
+                BOOL isContact = [contactsManager.lastKnownContactRecipientIds containsObject:recipientId];
                 if (isContact) {
                     // Only create "add to contacts" offers for non-contacts.
                     shouldHaveAddToContactsOffer = NO;