Fetching single tag in shallow clone almost unshallow the clone

From: Bagas Sanjaya <bagasdotme@gmail.com>
Date: May 28, 2021, 07:03 UTC
Message-ID: <304633fd-e677-7956-6787-f60f195db9b5@gmail.com>

Hi,

I have a copy of Golang repository [1] on my local Git server on my computer. I'm experimenting with fetching single tags in shallow clone.

I begin with shallow clone the repo:

$ git clone https://<myhost>/path/to/go.git --depth 200 golang $ cd golang

Because only one, default branch (master) is checked out on shallow clone, I fetch latest release branch shallowly:

$ git remote set-branches --add origin release-branch.go1.16 $ git fetch origin release-branch.go1.16 --depth 25

Then I fetch single tag only, that is latest tagged release:

$ git fetch origin tag go1.16.4 --no-tags

> From https://<myhost>/path/to/go
>  * [new tag]           go1.16.4   -> go1.16.4

That above worked, because the commit the tag refers to is already on the clone.

But when I fetch a single tag which the commit the tag refers to isn't already on the clone, Git fetched almost the entire history (thus almost unshallow the clone):

$ git fetch origin tag go1.16.1 --no-tags

Show 8 quoted lines

> remote: Enumerating objects: 436644, done.
> remote: Counting objects: 100% (427655/427655), done.
> remote: Compressing objects: 100% (75334/75334), done.
> remote: Total 419698 (delta 343975), reused 416121 (delta 341201), pack-reused 0
> Receiving objects: 100% (419698/419698), 146.94 MiB | 16.06 MiB/s, done.
> Resolving deltas: 100% (343975/343975), completed with 4892 local objects.
> From https://gitnode.io/bagas/go
>  * [new tag]           go1.16.1   -> go1.16.1

I expect that instead Git will deepen the shallow clone until the specified tag.

Note that I used "almost unshallow" phrase, because although almost the whole history had been fetched, `.git/shallow` still exists, meant that the clone was still shallow. To convert to full clone, I did `git fetch --unshallow`, which also fetched tags referenced on either master or already configured released branches.

Thanks.

[1]: https://github.com/golang/go

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