Creating diffs for some files fails

[joshaber]

This might be a relatively recently introduced bug.

We're trying to enable delta updates for GitHub Desktop (desktop/desktop#2239). With Squirrel.Windows 1.5.2, it works. With Squirrel.Windows 1.7.6, an exception is thrown creating deltas for some files:

DeltaPackageBuilder: We really couldn't create a delta for package.json: System.DivideByZeroException: Attempted to divide by zero.
   at Squirrel.Bsdiff.BinaryPatchUtility.Create(Byte[] oldData, Byte[] newData, Stream output)
   at Squirrel.DeltaPackageBuilder.createDeltaForSingleFile(FileInfo targetFile, DirectoryInfo workingDirectory, Dictionary`2 baseFileListing)

@Keboo mentioned hitting this same bug in #1087.

[anaisbetts]

I think we're just gonna revert all of these bsdiff changes, they're breaking stuff

[Thieum]

@joshaber are you still experiencing this issue with the latest version of Squirrel?

[shiftkey]

I'm tracking desktop/desktop#5197 to upgrade our version of electron-winstaller (that uses Squirrel) and I'll report back if we still see this issue later on.