Re: [PATCH] git.c: fix help.autocorrect after 57ea712 breaks it

> Commit 57ea712 (git.c: make sure we do not leak GIT_* to alias scripts -
> 2015-12-20) does not realize that handle_alias() can be called multiple
> times because of the forever loop in run_argv(). The commit breaks alias
> chains.
> 
> Suppose you have an alias "abc" that resolves to another alias "def",
> which finally resolve to "git status". handle_alias() is called twice.
> save_env() and restore_env() are also called twice. But because of the
> check save_env_before_alias in save_env(), we save once while trying to
> restore twice. Consequences are left for the reader's imagination.
> 
> Fortunately, you cannot make an alias of another alias. At least not
> yet. Unfortunately it can still happen with help.autocorrect, where your
> alias typo is treated as the first "alias", and it can be resolved to
> the second alias. Then boom.
> 
> Make sure we call save_env() and restore_env() in pairs. While at there,
> set orig_cwd to NULL after freeing it for hygiene.
> 
> Reported-by: Michael J Gruber <git@drmicha.warpmail.net>
> Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
> ---