Re: [PATCH] small memory leak fix

From: Stefan Beller <sbeller@google.com>
Date: May 1, 2017, 20:50 UTC
Message-ID: <CAGZ79kYfoBOc+hVhm7XEg1TvYQ8myF4f=0wSwDs-agYxaArsWQ@mail.gmail.com>
In-Reply-To: <C3A43A45-9120-4755-AE42-FD33F68F3FCB@gmail.com>

On Mon, May 1, 2017 at 1:40 PM, David CARLIER <devnexen@gmail.com> wrote:

> Hi this is my first submission, a memory leak found in the maint branch (might be in master as well).
>
> Kind regards.

Hi and welcome to Git!

> From d98f3944780730447f111a4178c9d99f5110c260 Mon Sep 17 00:00:00 2001
> From: David Carlier <devnexen@gmail.com>
> Date: Mon, 1 May 2017 21:14:09 +0100
> Subject: [PATCH] memory leaks fixes for remote lists.

We usually word the subject line as "area: what we do" (C.f. $ git log --oneline --no-merges -- remote.c) Maybe:

    remote.c: plug memleak in for_each_remote

Show 19 quoted lines

>
> both push and fetch lists were not freed thus
> using free_refspecs usage.
>
> Signed-off-by: David Carlier <devnexen@gmail.com>
> ---
> remote.c | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/remote.c b/remote.c
> index 9f83fe2c4..2f8cb35a3 100644
> --- a/remote.c
> +++ b/remote.c
> @@ -742,6 +742,8 @@ int for_each_remote(each_remote_fn fn, void *priv)
>  r->push = parse_push_refspec(r->push_refspec_nr,
>      r->push_refspec);
>  result = fn(r, priv);
> + free_refspecs(r->push, r->push_refspec_nr);
> + free_refspecs(r->fetch, r->fetch_refspec_nr);

After freeing the refspec, r->push/fetch still points to the (now free'd) memory. We'd want to reset it to NULL as well, such that e.g. in this function

    if (!r->fetch)
        ...

still works.

After reading this, I think we'd rather want to keep the fetch/push refspec around for the next access of the struct remote, and only free the memory when the remote itself is freed?

That however is a problem as we never free them, they are globals :(

Thanks, Stefan