From: Marc Strapetz <marc.strapetz@syntevo.com>
Date: Thu, 08 Jun 2017 11:52:13 GMT
Subject: git stash --include-untracked possible destructive behavior
Message-ID: <2b695c73-9de2-5502-6d19-ba4ad0114978@syntevo.com>

One of our users has just discovered a destructive behavior of git stash 
--include-untracked: ignored files within non-ignored directories will 
not be stashed as untracked files (expected), but will still be removed 
from the working tree. The problem is reproducible by following command 
sequence:

   $ git init
   $ echo "1" > file.txt
   $ mkdir Data
   $ echo "1" > Data/ignored.txt
   $ echo "Data/*" > .gitignore
   $ git add .
   $ git commit -m "initial import"
   $ echo "2" > file.txt
   $ git stash save --include-untracked
   Saved working directory and index state WIP on master: 6ce5303 initial
   import

   $ git stash show stash@{1}
    file.txt | 2 +-
    1 file changed, 1 insertion(+), 1 deletion(-)

   $ ls Data
   ls: cannot access 'Data': No such file or directory

As you can see, after saving the stash, stash@{1} doesn't contain 
Data/ignored.txt, but the entire Data directory is still gone from the 
working tree. As a consequence, applying the stash won't bring back 
Data/ignored.txt, too.

   $ git stash apply
   On branch master
   Changes not staged for commit:
     (use "git add <file>..." to update what will be committed)
     (use "git checkout -- <file>..." to discard changes in working
     directory)

           modified:   file.txt

   no changes added to commit (use "git add" and/or "git commit -a")

   $ ls Data
   ls: cannot access 'Data': No such file or directory

Note that when changing .gitignore to "Data/" instead of "Data/*", 
--include-untracked works as expected.

Tested with: git version 2.13.0.windows.1

-Marc