Re: [BUG] grep --recurse-submodules <tree> dies on a directory inside a submodule

> Hi,
> 
> Since Git 2.56.0, "git grep --recurse-submodules <pattern> <tree>"
> dies when it reaches a directory inside a submodule:
>     fatal: unable to read tree (<id of that directory's tree>)
> 
> The working-tree form ("git grep --recurse-submodules <pattern>") is
> not affected, and neither is a submodule with no directories. Our CI
> passed the same case on 2.55.0.
> 
> What did you do before the bug happened? (Steps to reproduce your issue)
> 
>     #!/bin/sh
>     set -e
>     work=$(mktemp -d)
>     cd "$work"
> 
>     git init -q sub
>     mkdir sub/dir
>     echo hello >sub/top
>     echo hello >sub/dir/nested
>     git -C sub add top dir/nested
>     git -C sub -c user.name=t -c user.email=t@t commit -qm sub
> 
>     git init -q super
>     git -C super -c protocol.file.allow=always \
>         submodule --quiet add "$work/sub" sub
>     git -C super -c user.name=t -c user.email=t@t commit -qm super
> 
>     git -C super grep --recurse-submodules -e hello HEAD
> 
> What did you expect to happen? (Expected behavior)
> 
>     HEAD:sub/dir/nested:hello
>     HEAD:sub/top:hello
> 
> What happened instead? (Actual behavior)
> 
>     fatal: unable to read tree (935cff11a11f8734cf4e0d40955d1e0e5c12038e)
> 
> with exit status 128. The id is that of the tree of sub/dir.