Re: [PATCH] submodule: fix NULL correctness in renamed broken submodules

> When fetching with recursing into submodules, the fetch logic inspects
> the superproject which submodules actually need to be fetched. This is
> tricky for submodules that were renamed in the fetched range of commits.
> This was implemented in c68f8375760 (implement fetching of moved
> submodules, 2017-10-16), and this patch fixes a mistake in the logic
> there.
> 
> When the warning is printed, the `name` might be NULL as
> default_name_or_path can return NULL, so fix the warning to use the path
> as obtained from the diff machinery, as that is not NULL.
> 
> While at it, make sure we only attempt to load the submodule if a git
> directory of the submodule is found as default_name_or_path will return
> NULL in case the git directory cannot be found. Note that passing NULL
> to submodule_from_name is just a semantic error, as submodule_from_name
> accepts NULL as a value, but then the return value is not the submodule
> that was asked for, but some arbitrary other submodule. (Cf. 'config_from'
> in submodule-config.c: "If any parameter except the cache is a NULL
> pointer just return the first submodule. Can be used to check whether
> there are any submodules parsed.")
> 
> Reported-by: Duy Nguyen <pclouds@gmail.com>
> Helped-by: Duy Nguyen <pclouds@gmail.com>
> Helped-by: Heiko Voigt <hvoigt@hvoigt.net>
> Signed-off-by: Stefan Beller <sbeller@google.com>
> ---