Re: [PATCH] submodule add: improve message when resolving a relative url fails

From: Phil Hord <hordp@cisco.com>
Date: Jul 27, 2011, 19:00 UTC
Message-ID: <4E306065.2010002@cisco.com>
In-Reply-To: <4DE660E2.9080500@xiplink.com>

On 06/01/2011 11:55 AM, Marc Branchaud wrote:

Show 25 quoted lines

> On 11-05-31 06:04 PM, Phil Hord wrote:
>> On 05/31/2011 04:57 PM, Marc Branchaud wrote:
>>>  - The current code rewrites the URL so that any relative path is either
>>>    rejected or munged into an absolute remote URL.
>> I don't see the URL getting munged away from being relative.  Can you
>> point to an example?
> I reached this conclusion because if I go into my clone of git.git and do
>
> 	git submodule add ../MyThing
>
> where ../MyThing is a regular git repo, I get
>
> Cloning into MyThing...
> fatal: The remote end hung up unexpectedly
> Clone of 'git://git.kernel.org/pub/scm/git/MyThing' into submodule path
> 'MyThing' failed
>
> So it seemed the relative URL became an absolute URL.
>
> Looking more closely at a working example, I can see that (as you show below)
> the URL in the super-repo's .gitmodules file retains the relative path, but
> the submodule's remote.origin.url is an absolute path.
>
> In any case, "submodule add" isn't doing what I expected: make my local
> MyThing repo a submodule of my git.git clone.

I thought I understood this workflow better than I actually did. I think I understand more now, and I'm somewhat disappointed. But I also failed to pick up the ball on this old discussion.

If you do this, I think it will work like you were hoping:

    :: ( mkdir MyThing && cd MyThing && git init )
    Initialized empty Git repository in /opc/git/MyThing/.git/
    :: git submodule add ../MyThing
    Adding existing repo at 'MyThing' to the index

I haven't examined the code, but I think this is how it works.  'git
submodule add' takes a URL and a local path.  When you omit the local
path, git infers one from the URL.  So these two commands are equivalent:
    :: git submodule add ../MyThing
    :: git submodule add ../MyThing MyThing

If the path you provide (explicitly or implicitly) already contains a git repo, it is assumed to be "the" submodule repo and git uses it. If it does not contain a git repo, git attempts to clone it from the (remote) URL.

Furthermore, the relative path only works for URLs. It does not work for local filesystems.

Phil