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

[Johannes Schindelin <Johannes.Schindelin@gmx.de>]

Hi Peff & Thomas,

On Mon, 15 Feb 2016, Jeff King wrote:

> 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.

Yes, yes, yes. Y'all are absolutely correct. I shoulda added a test case
right away, to make sure not only that what I fixed does not get broken in
the future, but also to document *what* was fixed, exactly.

So, belatedly, here goes a patch that verifies what that commit was
supposed to fix, and yes, it passes with Thomas' changes (Junio, would you
please apply this on top of tg/git-remote?):

-- snipsnap --
From: Johannes Schindelin <johannes.schindelin@gmx.de>
Date: Wed, 17 Feb 2016 14:45:59 +0100
Subject: [PATCH] t5505: 'remote add x y' should work when url.y.insteadOf = x

This is the test missing from fb86e32 (git remote: allow adding
remotes agreeing with url.<...>.insteadOf, 2014-12-23): we should
allow adding a remote with the URL when it agrees with the
url.<...>.insteadOf setting.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
---
 t/t5505-remote.sh | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/t/t5505-remote.sh b/t/t5505-remote.sh
index 94079a0..19e8e34 100755
--- a/t/t5505-remote.sh
+++ b/t/t5505-remote.sh
@@ -51,6 +51,11 @@ test_expect_success setup '
 	git clone one test
 '
 
+test_expect_success 'add remote whose URL agrees with url.<...>.insteadOf' '
+	git config url.git@host.com:team/repo.git.insteadOf myremote &&
+	git remote add myremote git@host.com:team/repo.git
+'
+
 test_expect_success C_LOCALE_OUTPUT 'remote information for the origin' '
 	(
 		cd test &&
-- 
2.7.1.windows.2