Change Address from Sparrow No Longer Shown

[shannona]

When Sparrow generates a transaction with change, GST no longer recognizes the money sent back to the same key as change. (It used to properly differentiate it.) It's just an additional "sent" address instead.

[wolfmcnally]

Unfortunately, when we updated to a newer version of LibWally in this last iteration, which has better segwit support, the new version invalidated how change outputs were determined. The code we were using for this was originally inherited from an open source package. This code has been disabled, pending prioritization of figuring out the right way to do it now. So I'm going to change this to "enhancement," and we should prioritize it, as it may take some time to research, implement, and test. In the meantime, it would be useful to post a test vector here.

[shannona]

I've included a video of Sparrow's Animated QR as a Test Vector of a PSBT that should break out a change address:

IMG_6213.mov

I've also removed the bug tag.