On Wed, Apr 26, 2017 at 4:12 PM, Ævar Arnfjörð Bjarmason
<avarab@xxxxxxxxx> wrote:
> Add a --no-tags option to clone without fetching any tags.
>
> Without this change there's no easy way to clone a repository without
> also fetching its tags.
>
> When supplying --single-branch the primary remote branch will be
> cloned, but in addition tags will be followed & retrieved. Now
> --no-tags can be added --single-branch to clone a repository without
> tags, and which only tracks a single upstream branch.
>
> This option works without --single-branch as well, and will do a
> normal clone but not fetch any tags.
>
> Many git commands pay some fixed overhead as a function of the number
> of references. E.g. creating ~40k tags in linux.git will cause a
> command like `git log -1 >/dev/null` to run in over a second instead
> of in a matter of milliseconds, in addition numerous other things will
> slow down, e.g. "git log <TAB>" with the bash completion will slowly
> show ~40k references instead of 1.
>
> The user might want to avoid all of that overhead to simply use a
> repository like that to browse the "master" branch, or something like
> a CI tool might want to keep that one branch up-to-date without caring
> about any other references.
>
> Without this change the only way of accomplishing this was either by
> manually tweaking the config in a fresh repository:
>
> git init git &&
> cat >git/.git/config <<EOF &&
> [remote "origin"]
> url = git@xxxxxxxxxx:git/git.git
> tagOpt = --no-tags
> fetch = +refs/heads/master:refs/remotes/origin/master
> [branch "master"]
> remote = origin
> merge = refs/heads/master
> EOF
> cd git &&
> git pull
>
> Which requires hardcoding the "master" name, which may not be the main
> --single-branch would have retrieved, or alternatively by setting
> tagOpt=--no-tags right after cloning & deleting any existing tags:
>
> git clone --single-branch git@xxxxxxxxxx:git/git.git &&
> cd git &&
> git config remote.origin.tagOpt --no-tags &&
> git tag -l | xargs git tag -d
>
> Which of course was also subtly buggy if --branch was pointed at a
> tag, leaving the user in a detached head:
>
> git clone --single-branch --branch v2.12.0 git@xxxxxxxxxx:git/git.git &&
> cd git &&
> git config remote.origin.tagOpt --no-tags &&
> git tag -l | xargs git tag -d
>
> Now all this complexity becomes the much simpler:
>
> git clone --single-branch --no-tags git@xxxxxxxxxx:git/git.git
>
> Or in the case of cloning a single tag "branch":
>
> git clone --single-branch --branch v2.12.0 --no-tags git@xxxxxxxxxx:git/git.git
>
> Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@xxxxxxxxx>
I like the option, though I dislike the implementation, specifically as you
brought up e.g. "[PATCH] various: disallow --no-no-OPT for --no-opt options".
Can we have an option "--tags" instead, which is on by default
and then you can negate it to --no-tags, without having to worry
about the no-no case.
The problem with tags is that they are in a shared name-space
and not part of the remote refspec. If they were, the documentation
would be way easier, too going this way.
> +--no-tags::
> + Don't clone any tags, and set
> + `remote.<remote>.tagOpt=--no-tags` in the config, ensuring
> + that future `git pull` and `git fetch` operations won't follow
> + any tags. Subsequent explicit tag fetches will still work,
> + (see linkgit:git-fetch[1]).
> ++
> +Can be used in conjunction with `--single-branch` to clone and
> +maintain a branch with no references other than a single cloned
> +branch. This is useful e.g. to maintain minimal clones of the default
> +branch of some repository for search indexing.
In the future we may want to have '--depth' also imply --no-tags,
just as it implies --single-branch.
> @@ -652,7 +655,7 @@ static void update_remote_refs(const struct ref *refs,
>
> if (refs) {
> write_remote_refs(mapped_refs);
> - if (option_single_branch)
> + if (option_single_branch && !option_no_tags)
I am debating if this needs to be an || instead of &&, as you would not
want to write the tags with "--no-single-branch --no-tags" ?
Thanks,
Stefan