[BUG} stash show does not show untracked files stashed (reposted)

[<randall.s.becker@rogers.com>]

I don't know whether this is new behaviour following changes to stash, but
here goes.

Suppose I have files a,b,c,d modified, but only file d is in the index.
After stash push  (or save) --include-untracked, stash show only displays
file d. A subsequent pop will restore files a,b,c,d. So functionally push
and pop are fine, but stash show appears to ignores files in the stash. The
git log below shows a previous commit (dce2e3e) to the WIP stash (ab0834c)
that does contain the untracked files, and git diff is happy to show the
contents when using the ref directly. It is just counterintuitive for stash
show not to display all entries previously pushed. I would have expected
symmetry. This is not new.

*-.   ab0834c (refs/stash) WIP on master: bf223fc Updated known
|\ \
| | * dce2e3e untracked files on master: bf223fc Updated known
| * a5ad1ef index on master: bf223fc Updated known
|/
* bf223fc (HEAD -> master) Updated known
* db0efd4 (origin/master, origin/HEAD) initial

This on git 2.23.0. I have the same behaviour on the Windows build of git
2.12.3.

builtins/stash.c show_stash() does not look like it accounts for multiple
paths when calling setup_revisions, so I think it is missing the path to the
untracked file ref (dce2e32). I am guessing.

Thanks,
Randall

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