Git Stash Prevention from Reset Phased Files

Question

Assume the following scenario:

file a and b both changed, and a is placed in the index. If you run git stash and then git stash pop , file a will no longer be installed.

How do you do git stash to return an index to a previous state?

Answer 1

If I understand correctly, I think you just need to:

 git stash pop --index