Does `git stash push` not stash unstaged changes?

Question

Does git stash push not stash unstaged changes?

$ touch testfile
$ git stash push
No local changes to save

Why does it work for staged changes now?

$ git add testfile 
$ git stash push
Saved working directory and index state WIP on mybranch: e5c1660  add note

Thanks.

Answer 1

The git stash code saves, by default, ¹ exactly and only the tracked files. An untracked file is a file that is in the work-tree, but not in the index. Such a file is not going to be in the next commit you make, if you make a commit right now, whether or not the file is listed in a .gitignore .

Once the file is in the index, it will be in the next commit you make, whether or not it is listed in a .gitignore . So, once you git add testfile , there is something in the index that does not match something in HEAD and git stash is willing to make commits from both the index and work-tree. The git stash command (with no extra options) will save ² the index and work-tree if either one differs from HEAD , but will do nothing if both exactly match HEAD .

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¹ I'm deliberately ignoring, here, the option to run git stash save -u or git stash save -a . These make a stash that includes three commits instead of two. It also changes the cleaning action that git stash save executes. A later git stash apply or git stash pop of a three-commit stash works somewhat differently from the later git stash apply or git stash pop of a two-commit stash, as well, though this answer does not address the later git stash apply or git stash pop at all.

² The push verb in git stash push is simply the opposite of the pop verb in git stash pop ; it has nothing to do with git push . Back in the old days, git stash did not have a push sub-command. Some people noted that git stash had some weird syntactic issues and this asymmetry—pop without push—so eventually git stash acquired a push sub-command with better syntax and the ability to stash just some subset of files.

Note that when using the subset feature, the I and W commits you mentioned here are still full snapshots; it's just that the W snapshot only adds the specified subset files, and then the subsequent git reset + checkout that git stash runs only resets the specified subset as well. There was a very nasty, data-destroying bug in this new feature for several Git revisions: git stash push <subset> would save the subset, then reset too many files.