Bug: "git status --porcelain --show-stash" does not show stash count

Using:

   $ git version
    git version 2.15.1

Running without --porcelain shows the correct stash count:

    $ git status --show-stash
    On branch feature-Enable-Unmarshaling-Support
    Untracked files:
      (use "git add <file>..." to include in what will be committed)

            testdata/

    nothing added to commit but untracked files present (use "git add" to track)
    Your stash currently has 1 entry

Notice the last line in that output, "Your stash currently has 1 entry."

But the output when adding --porcelain does not output anything for stash counts:

    $ git status --porcelain --show-stash
    ?? testdata/

Version 2 does not either:

    $ git status --porcelain=2 --show-stash
    ? testdata/

Also, the --short option seems to be a shortcut to --porcelain with color coding (and still doesn't show the stash count):

    $ git status --short --show-stash
    ?? testdata/

I would expect something like "SS 1" or "S 1" to show stashes with a count of 1.

Thanks! Eric