Subject: problems serving non-bare repos with submodules over http

From: Yaroslav Halchenko <[email-masked]>
Date: Wed, 20 Apr 2016 11:22:09 -0400

Dear Git Folks,

I do realize that the situation is quite uncommon, partially I guess due
to git submodules mechanism flexibility and power on one hand and
under-use (imho) on the other, which leads to discovery of regressions
[e.g. 1] and corner cases as mine.

[1] http://thread.gmane.org/gmane.comp.version-control.git/288064
[2] http://www.onerussian.com/tmp/git-web-submodules.sh

My use case:  We are trying to serve a git repository with submodules
specified with relative paths over http from a simple web server.  With a demo
case and submodule specification [complete script to reproduce including the
webserver using python is at 2] such as

(git)hopa:/tmp/gitxxmsxYFO[master]git
$> tree
.
├── f1
└── sub1
    └── f2

$> cat .gitmodules
[submodule "sub1"]
    path = sub1
    url = ./sub1

1. After cloning 

    git clone http://localhost:8080/.git

   I cannot 'submodule update' the sub1 in the clone since its url after
   'submodule init' would be  http://localhost:8080/.git/sub1 .  If I manually fix
   it up -- it seems to proceed normally since in original repository I have
   sub1/.git/ directory and not the "gitlink" for that submodule.

2. If I serve the clone [2 demos that too] itself, there is no easy remedy at
   all since sub1/.git is not a directory but a gitlink.

N.B. I haven't approached nested submodules case yet in [2]

I wondered

a. could 'git clone' (probably actually some relevant helper used by fetch
   etc) acquire ability to sense for URL/.git if URL itself doesn't point to a
   usable git repository?

    I think this could provide complete remedy for 1 since then relative urls
    would be properly assembled, with similar 'sensing' for /.git for the final urls

    I guess we could do it with rewrites/forwards on the "server side",
    but it wouldn't be generally acceptable solution.

b. is there a better or already existing way to remedy my situation?

c. shouldn't "git clone" (or the relevant helper) be aware of remote
   /.git possibly being a gitlink file within submodule?

Thank you in advance for your thoughts and feedback on this case.

P.S. Please maintain the CC list in replies.
-- 
Yaroslav O. Halchenko
Center for Open Neuroscience     http://centerforopenneuroscience.org
Dartmouth College, 419 Moore Hall, Hinman Box 6207, Hanover, NH 03755
Phone: +1 (603) 646-9834                       Fax: +1 (603) 646-1419
WWW:   http://www.linkedin.com/in/yarik