Fix handling of HEIF/HEIC when attaching image "as document."

SignalMessaging/attachments/SignalAttachment.swift

@@ -603,7 +603,8 @@ public class SignalAttachment: NSObject {
             }
             attachment.cachedImage = image
 
-            if isValidOutputImage(image: image, dataSource: dataSource, dataUTI: dataUTI, imageQuality:imageQuality) {
+            let isValidOutput = isValidOutputImage(image: image, dataSource: dataSource, dataUTI: dataUTI, imageQuality: imageQuality)
+
             if let sourceFilename = dataSource.sourceFilename,
                 let sourceFileExtension = sourceFilename.fileExtension,
                 ["heic", "heif"].contains(sourceFileExtension.lowercased()) {
@@ -616,26 +617,27 @@ public class SignalAttachment: NSObject {
                 // updating the extension as well. No problem.
                 // However the problem comes in when you edit an HEIC image in Photos.app - the image is saved
                 // in the Photos.app as a JPEG, but retains the (now incongruous) HEIC extension in the filename.
-                    assert(dataUTI == kUTTypeJPEG as String)
+                assert(dataUTI == kUTTypeJPEG as String || !isValidOutput)
                 Logger.verbose("\(self.TAG) changing extension: \(sourceFileExtension) to match jpg uti type")
 
                 let baseFilename = sourceFilename.filenameWithoutExtension
                 dataSource.sourceFilename = baseFilename.appendingFileExtension("jpg")
             }
 
+            if isValidOutput {
                 Logger.verbose("\(TAG) Sending raw \(attachment.mimeType)")
                 return attachment
-            }
+            } else {
-
                 Logger.verbose("\(TAG) Compressing attachment as image/jpeg, \(dataSource.dataLength()) bytes")
                 return compressImageAsJPEG(image: image, attachment: attachment, filename: dataSource.sourceFilename, imageQuality: imageQuality)
             }
         }
+    }
 
     // If the proposed attachment already conforms to the
     // file size and content size limits, don't recompress it.
     private class func isValidOutputImage(image: UIImage?, dataSource: DataSource?, dataUTI: String, imageQuality: TSImageQuality) -> Bool {
-        guard let image = image else {
+        guard image != nil else {
             return false
         }
         guard let dataSource = dataSource else {
@@ -644,7 +646,6 @@ public class SignalAttachment: NSObject {
         guard SignalAttachment.outputImageUTISet.contains(dataUTI) else {
             return false
         }
-
         if doesImageHaveAcceptableFileSize(dataSource: dataSource, imageQuality: imageQuality) &&
             dataSource.dataLength() <= kMaxFileSizeImage {
             return true
@@ -682,7 +683,8 @@ public class SignalAttachment: NSObject {
         assert(attachment.error == nil)
 
         if imageQuality == .original &&
-            attachment.dataLength < kMaxFileSizeGeneric {
+            attachment.dataLength < kMaxFileSizeGeneric &&
+            outputImageUTISet.contains(attachment.dataUTI) {
             // We should avoid resizing images attached "as documents" if possible.
             return attachment
         }