The old `allocfmt` is of no use to callers, as they are not able to free
the returned buffer. Export a new API that returns a static string that
doesn't need to be freed.
When diff finds an untracked directory, it emulates Git behavior
by looking inside the directory to see if there are any untracked
items inside it. If there are only ignored items inside the dir,
then diff considers it ignored, even if there is no direct ignore
rule for it.
Checkout was not copying this behavior - when it found an untracked
directory, it just treated it as untracked. Unfortunately, when
combined with GIT_CHECKOUT_REMOVE_UNTRACKED, this made is seem that
checkout (and stash, which uses checkout) was removing ignored
items when you had only asked it to remove untracked ones.
This commit moves the logic for advancing past an untracked dir
while scanning for non-ignored items into an iterator helper fn,
and uses that for both diff and checkout.
To emulate git, stash should not remove untracked git repositories
inside the parent repo, and checkout's REMOVE_UNTRACKED should
also skip over these items.
`git stash` actually prints a warning message for these items.
That should be possible with a checkout notify callback if you
wanted to, although it would require a bit of extra logic as things
are at the moment.
`git_submodule` objects were already refcounted internally in case
the submodule name was different from the path at which it was
stored. This makes that refcounting externally used as well, so
`git_submodule_lookup` and `git_submodule_add_setup` return an
object that requires a `git_submodule_free` when done.
Any well-behaved program should write a descriptive message to the
reflog whenever it updates a reference. Let's make this more prominent
by removing the version without the reflog parameters.
