Re: [PATCH 4/4] remote: use remote_is_configured() for add and rename

[Jeff King <peff@peff.net>]

On Mon, Feb 15, 2016 at 06:42:30PM +0100, Thomas Gummerer wrote:

> Both remote add and remote rename use a slightly different hand-rolled
> check if the remote exits.  The hand-rolled check may have some subtle
> cases in which it might fail to detect when a remote already exists.
> One such case was fixed in fb86e32 ("git remote: allow adding remotes
> agreeing with url.<...>.insteadOf").  Another case is when a remote is
> configured as follows:
> 
>   [remote "foo"]
>     vcs = bar
> 
> If we try to run `git remote add foo bar` with the above remote
> configuration, git segfaults.  This change fixes it.
> 
> In addition, git remote rename $existing foo with the configuration for
> foo as above silently succeeds, even though foo already exists,
> modifying its configuration.  With this patch it fails with "remote foo
> already exists".

Checking is_configured() certainly sounds like a better test, but...

> diff --git a/builtin/remote.c b/builtin/remote.c
> index 981c487..bd57f1b 100644
> --- a/builtin/remote.c
> +++ b/builtin/remote.c
> @@ -186,10 +186,7 @@ static int add(int argc, const char **argv)
>  	url = argv[1];
>  
>  	remote = remote_get(name);
> -	if (remote && (remote->url_nr > 1 ||
> -			(strcmp(name, remote->url[0]) &&
> -				strcmp(url, remote->url[0])) ||
> -			remote->fetch_refspec_nr))
> +	if (remote_is_configured(remote))
>  		die(_("remote %s already exists."), name);

This original is quite confusing. I thought at first that there was
perhaps something going on with allowing repeated re-configuration of
the same remote, as long as some parameters matched. I.e., I am
wondering if there is a case here that does _not_ segfault, that we
would be breaking.

But reading over fb86e32dcc, I think I have convinced myself that it was
merely an ad-hoc check for "is_configured", and using that function is a
better replacement.

-Peff