Fix "413 on prekey fetch" errors.

SignalServiceKit/src/Contacts/Contact.m

@@ -212,8 +212,9 @@ NS_ASSUME_NONNULL_BEGIN
     __block NSMutableArray *result = [NSMutableArray array];
 
     for (PhoneNumber *number in [self.parsedPhoneNumbers sortedArrayUsingSelector:@selector(compare:)]) {
-        SignalRecipient *_Nullable signalRecipient =
-            [SignalRecipient registeredRecipientForRecipientId:number.toE164 transaction:transaction];
+        SignalRecipient *_Nullable signalRecipient = [SignalRecipient registeredRecipientForRecipientId:number.toE164
+                                                                                        mustHaveDevices:YES
+                                                                                            transaction:transaction];
         if (signalRecipient) {
             [result addObject:signalRecipient];
         }

SignalServiceKit/src/Contacts/SignalRecipient.h

@@ -21,6 +21,7 @@ NS_ASSUME_NONNULL_BEGIN
 - (instancetype)init NS_UNAVAILABLE;
 
 + (nullable instancetype)registeredRecipientForRecipientId:(NSString *)recipientId
+                                           mustHaveDevices:(BOOL)mustHaveDevices
                                                transaction:(YapDatabaseReadTransaction *)transaction;
 + (instancetype)getOrBuildUnsavedRecipientForRecipientId:(NSString *)recipientId
                                              transaction:(YapDatabaseReadTransaction *)transaction;

SignalServiceKit/src/Contacts/SignalRecipient.m

@@ -41,8 +41,9 @@ NS_ASSUME_NONNULL_BEGIN
 {
     OWSAssertDebug(transaction);
     OWSAssertDebug(recipientId.length > 0);
-    
-    SignalRecipient *_Nullable recipient = [self registeredRecipientForRecipientId:recipientId transaction:transaction];
+
+    SignalRecipient *_Nullable recipient =
+        [self registeredRecipientForRecipientId:recipientId mustHaveDevices:NO transaction:transaction];
     if (!recipient) {
         recipient = [[self alloc] initWithTextSecureIdentifier:recipientId];
     }
@@ -96,16 +97,17 @@ NS_ASSUME_NONNULL_BEGIN
 }
 
 + (nullable instancetype)registeredRecipientForRecipientId:(NSString *)recipientId
+                                           mustHaveDevices:(BOOL)mustHaveDevices
                                                transaction:(YapDatabaseReadTransaction *)transaction
 {
     OWSAssertDebug(transaction);
     OWSAssertDebug(recipientId.length > 0);
 
     SignalRecipient *_Nullable signalRecipient = [self fetchObjectWithUniqueID:recipientId transaction:transaction];
-    if (signalRecipient.devices.count > 0) {
-        return signalRecipient;
+    if (mustHaveDevices && signalRecipient.devices.count < 1) {
+        return nil;
     }
-    return nil;
+    return signalRecipient;
 }
 
 - (void)addDevices:(NSSet *)devices
@@ -217,8 +219,7 @@ NS_ASSUME_NONNULL_BEGIN
 
 + (BOOL)isRegisteredRecipient:(NSString *)recipientId transaction:(YapDatabaseReadTransaction *)transaction
 {
-    SignalRecipient *_Nullable instance = [self registeredRecipientForRecipientId:recipientId transaction:transaction];
-    return instance.devices.count > 0;
+    return nil != [self registeredRecipientForRecipientId:recipientId mustHaveDevices:YES transaction:transaction];
 }
 
 + (SignalRecipient *)markRecipientAsRegisteredAndGet:(NSString *)recipientId
@@ -227,7 +228,8 @@ NS_ASSUME_NONNULL_BEGIN
     OWSAssertDebug(transaction);
     OWSAssertDebug(recipientId.length > 0);
 
-    SignalRecipient *_Nullable instance = [self registeredRecipientForRecipientId:recipientId transaction:transaction];
+    SignalRecipient *_Nullable instance =
+        [self registeredRecipientForRecipientId:recipientId mustHaveDevices:YES transaction:transaction];
 
     if (!instance) {
         OWSLogDebug(@"creating recipient: %@", recipientId);
@@ -262,7 +264,9 @@ NS_ASSUME_NONNULL_BEGIN
     SignalRecipient *instance = [self getOrBuildUnsavedRecipientForRecipientId:recipientId
                                                                    transaction:transaction];
     OWSLogDebug(@"Marking recipient as not registered: %@", recipientId);
-    [instance removeDevices:instance.devices.set];
+    if (instance.devices.count > 0) {
+        [instance removeDevices:instance.devices.set];
+    }
     [instance saveWithTransaction_internal:transaction];
 }
 

SignalServiceKit/src/Messages/OWSMessageManager.m

@@ -1456,7 +1456,7 @@ NS_ASSUME_NONNULL_BEGIN
     // Consult the device list cache we use for message sending
     // whether or not we know about this linked device.
     SignalRecipient *_Nullable recipient =
-        [SignalRecipient registeredRecipientForRecipientId:localNumber transaction:transaction];
+        [SignalRecipient registeredRecipientForRecipientId:localNumber mustHaveDevices:NO transaction:transaction];
     if (!recipient) {
         OWSFailDebug(@"No local SignalRecipient.");
     } else {