Better error messages when failure to send due to:

- no internet
- unregistered recipient

// FREEBIE

src/Messages/OWSMessageSender.m

@@ -270,9 +270,8 @@ NSString *const OWSMessageSenderInvalidDeviceException = @"InvalidDeviceExceptio
                 ? self.storageManager.localNumber
                 : contactThread.contactIdentifier;
 
-            __block SignalRecipient *recipient = [SignalRecipient recipientWithTextSecureIdentifier:recipientContactId];
+            SignalRecipient *recipient = [SignalRecipient recipientWithTextSecureIdentifier:recipientContactId];
             if (!recipient) {
-
                 NSError *error;
                 // possibly returns nil.
                 recipient = [self.contactsUpdater synchronousLookup:contactThread.contactIdentifier error:&error];
@@ -281,6 +280,8 @@ NSString *const OWSMessageSenderInvalidDeviceException = @"InvalidDeviceExceptio
                     if (error.code == NOTFOUND_ERROR) {
                         DDLogWarn(@"recipient contact not found with error: %@", error);
                         [self unregisteredRecipient:recipient message:message thread:thread];
+                        NSError *error = OWSErrorMakeNoSuchSignalRecipientError();
+                        return failureHandler(error);
                     }
                     DDLogError(@"contact lookup failed with error: %@", error);
                     return failureHandler(error);
@@ -462,7 +463,7 @@ NSString *const OWSMessageSenderInvalidDeviceException = @"InvalidDeviceExceptio
             switch (statuscode) {
                 case 404: {
                     [self unregisteredRecipient:recipient message:message thread:thread];
-                    NSError *error = OWSErrorMakeFailedToSendOutgoingMessageError();
+                    NSError *error = OWSErrorMakeNoSuchSignalRecipientError();
                     return failureHandler(error);
                 }
                 case 409: {

src/Network/API/TSNetworkManager.m

@@ -135,7 +135,8 @@ typedef void (^failureBlock)(NSURLSessionDataTask *task, NSError *error);
               DDLogWarn(@"The network request failed because of a connectivity error.");
               failureBlock(task,
                   [self errorWithHTTPCode:statusCode
-                                       description:NSLocalizedString(@"NETWORK_ERROR_DESC", nil)
+                              description:NSLocalizedString(@"ERROR_DESCRIPTION_NO_INTERNET",
+                                              @"Generic error used whenver Signal can't contact the server")
                             failureReason:networkError.localizedFailureReason
                        recoverySuggestion:NSLocalizedString(@"NETWORK_ERROR_RECOVERY", nil)
                             fallbackError:networkError]);

src/Util/OWSError.h

@@ -19,5 +19,6 @@ typedef NS_ENUM(NSInteger, OWSErrorCode) {
 extern NSError *OWSErrorWithCodeDescription(OWSErrorCode code, NSString *description);
 extern NSError *OWSErrorMakeUnableToProcessServerResponseError();
 extern NSError *OWSErrorMakeFailedToSendOutgoingMessageError();
+extern NSError *OWSErrorMakeNoSuchSignalRecipientError();
 
 NS_ASSUME_NONNULL_END

src/Util/OWSError.m

@@ -25,4 +25,11 @@ NSError *OWSErrorMakeFailedToSendOutgoingMessageError()
         NSLocalizedString(@"ERROR_DESCRIPTION_CLIENT_SENDING_FAILURE", @"Generic notice when message failed to send."));
 }
 
+NSError *OWSErrorMakeNoSuchSignalRecipientError()
+{
+    return OWSErrorWithCodeDescription(OWSErrorCodeFailedToSendOutgoingMessage,
+        NSLocalizedString(
+            @"ERROR_DESCRIPTION_UNREGISTERED_RECIPIENT", @"Error message when attempting to send message"));
+}
+
 NS_ASSUME_NONNULL_END