UE4 pak file with zero-length file did hide another file

Example:
- pak1.pak: file.uasset (15 kb)
- pak2.pak: file.uasset (0 bytes)

While scanning the game directory, the file from pak2 will replace previously loaded entry from pak1, with zero file length, what will make package inaccessible. Now, avoiding registraction of null files.

Author: gildor2

Unreal/FileSystem/UnArchivePak.cpp

@@ -739,9 +739,16 @@ bool FPakVFS::LoadPakIndexLegacy(FArchive* reader, const FPakInfo& info, FString
 		CompactFilePath(CombinedPath);
 		// serialize other fields
 		E.Serialize(InfoReader);
+
+		if (E.Size == 0)
+		{
+			// Happens with Jedi Fallen Order, seems assets are deleted in patches this way. If we'll continue registration,
+			// the existing (previous) asset might be overriden with zero-size file, and it won't be recognized as an asset anymore.
+			continue;
+		}
+
 		if (E.bEncrypted)
 		{
-//			appPrintf("Encrypted file: %s\n", *Filename);
 			NumEncryptedFiles++;
 		}
 		if (info.Version >= PakFile_Version_FNameBasedCompressionMethod)