Re: Can I fetch an arbitrary commit by sha1?

On Thu, Oct 2, 2014 at 9:57 AM, Christian Halstrick
[off-list ref] wrote:

I always though during fetch I have to specify a refspec and that a
sha1 would not be accepted as a ref. Firing some like 'git fetch
origin <sha1>' should be forbidden. But in fact I see that such a
fetch command succeeds if you already have that object in your local
repo.

My question: is it allowed to fetch sha1's? Shouldn't fetch fail if you try it?

See here:

quoted

git clone -q https://github.com/chalstrick/dondalfi.git
cd dondalfi
git ls-remote

From https://github.com/chalstrick/dondalfi.git
ce08dcc41104383f3cca2b95bd41e9054a957f5b HEAD
af00f4c39bcc8dc29ed8f59a47066d5993c279e4 refs/foo/b1
...

quoted

git show af00f4c39bcc8dc29ed8f59a47066d5993c279e4

fatal: bad object af00f4c39bcc8dc29ed8f59a47066d5993c279e4

quoted

git fetch origin af00f4c39bcc8dc29ed8f59a47066d5993c279e4

error: no such remote ref af00f4c39bcc8dc29ed8f59a47066d5993c279e4

quoted

git fetch origin refs/foo/b1

remote: Counting objects: 3, done.
remote: Compressing objects: 100% (2/2), done.
remote: Total 3 (delta 0), reused 0 (delta 0)
Unpacking objects: 100% (3/3), done.
From https://github.com/chalstrick/dondalfi
 * branch            refs/foo/b1 -> FETCH_HEAD

quoted

git fetch origin af00f4c39bcc8dc29ed8f59a47066d5993c279e4

From https://github.com/chalstrick/dondalfi
 * branch            af00f4c39bcc8dc29ed8f59a47066d5993c279e4 -> FETCH_HEAD

My understanding is that you are allowed to ask for a SHA1, but most
git servers refuse the request. But if you already have the SHA
locally, then git doesn't neet to bother asking the server for it, so
there's no request to be refused.

But it's been a while for me since I did any git development, so it's
possible I missed something.

-Dan