fix sending gif crash

Signal/src/ViewControllers/ConversationView/ConversationViewController.m

@@ -4098,6 +4098,14 @@ typedef enum : NSUInteger {
      didApproveAttachments:(NSArray<SignalAttachment *> *)attachments
                messageText:(NSString *_Nullable)messageText
 {
+    for (SignalAttachment *attachment in attachments) {
+        if ([attachment hasError]) {
+            OWSLogWarn(@"Invalid attachment: %@.", attachment ? [attachment errorName] : @"Missing data");
+            [self showErrorAlertForAttachment:attachment];
+            return;
+        }
+    }
+    
     [self tryToSendAttachments:attachments messageText:messageText];
     [self.inputToolbar clearTextMessageAnimated:NO];
     [self resetMentions];

SignalMessaging/ViewControllers/AttachmentApproval/AttachmentPrepViewController.swift

@@ -50,7 +50,9 @@ public class AttachmentPrepViewController: OWSViewController, PlayerProgressBarD
     init(attachmentItem: SignalAttachmentItem) {
         self.attachmentItem = attachmentItem
         super.init(nibName: nil, bundle: nil)
-        assert(!attachment.hasError)
+        if attachment.hasError {
+            owsFailDebug(attachment.error.debugDescription)
+        }
     }
 
     public required init?(coder aDecoder: NSCoder) {

SignalMessaging/ViewControllers/MediaMessageView.swift

@@ -63,7 +63,9 @@ public class MediaMessageView: UIView, OWSAudioPlayerDelegate {
     // of nice that it's written in a flexible way in case we'd want to use it elsewhere again in the future.
     @objc
     public required init(attachment: SignalAttachment, mode: MediaMessageViewMode) {
-        assert(!attachment.hasError)
+        if attachment.hasError {
+            owsFailDebug(attachment.error.debugDescription)
+        }
         self.attachment = attachment
         self.mode = mode
         super.init(frame: CGRect.zero)
@@ -336,7 +338,7 @@ public class MediaMessageView: UIView, OWSAudioPlayerDelegate {
         case .small, .large:
             return Colors.accent
         case .attachmentApproval:
-            return UIColor.white
+            return Colors.text
         }
     }