From: Nikita Bobko <nikitabobko@gmail.com>
Date: Mon, 23 Aug 2021 17:31:29 GMT
Subject: git read-tree doesn't accept tree-ish
Message-ID: <CAMJzOtxMjEuAy2B3oJqOZEnipmC4OBWxhQLx_baXDHcQ1C7-+g@mail.gmail.com>

```
git init
echo foo > foo
git add --all
git commit -m 'foo'

echo bar > foo
git add --all
git commit -m 'bar'

git read-tree HEAD~:foo
```
EXP: Read information about file `foo` into index
ACT: `fatal: failed to unpack tree object HEAD~:foo`

I expect it to work because manpage says that `git-read-tree` accepts
`<tree-ish>`