Re: [gentoo-dev] RFC: git-r3, additional clone types

[hasufell]

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Michał Górny:
>
> Single branch clone -------------------
>
> - git-2 eclass behavior,
>
> - only requested branch (or tag) is fetched, and tags on the
> commits fetched as part of the branch/tag history,
>
> - git notes are fetched,
>
> - EGIT_COMMIT can only name a commit in the fetched EGIT_BRANCH,
>
> - pruning unused branches/tags is hard (and possibly won't be
> implemented at first),
>
> - more efficient than the mirror mode, most likely future default.
>

I agree this should probably be the default.

>
> Shallow clone -------------
>
> - similar to old git-r3 behavior,
>
> - minimal number of objects from the requested branch (or tag) is
> fetched,
>
> - branch/tag history is not preserved,
>
> - git notes are not fetched,
>
> - EGIT_COMMIT can only name tags (using a hash auto-forces higher
> mode),
>
> - changing branches may be very inefficient (since it implies
> re-fetching all objects implied by --depth 1),
>
> - since the history is truncated, 'git describe' won't give pretty
> names,
>
> - most space-saving, intended for embedded and other special use
> cases,
>
> - does not guarantee repository consistency -- unsafe.
>
>
> Control variables -----------------
>
> I'm thinking of two control variables (better names appreciated):
>
> - EGIT_CLONE_MODE - set in make.conf by user to requested clone
> mode,
>
> - EGIT_MIN_CLONE_MODE - optionally set by ebuilds that require
> more.
>

Not a native english speaker, but EGIT_CLONE_TYPE and
EGIT_MIN_CLONE_TYPE sounds more natural to me.

>
>
> Mode upgrades and downgrades ----------------------------
>
> Mode is not associated persistently with a repository. Therefore,
> using a repository in a different mode than it was used before
> (e.g. due to different ebuild or user preference change) results in
> mixed-mode repository.
>
> When mirror or single-branch mode is used on a shallow repository,
> the repository is still marked 'shallow' even if the full history
> is available. I don't know if this wouldn't break some of 'git foo'
> uses in the checkout but that probably can't be predicted.
> Moreover, I don't know if it is safe to remove 'shallow' after
> doing full-fetch in mirror mode.
>
> When single-branch or shallow mode is used on a mirror-mode
> repository, only the requested branch/tag is updated. The
> repository may no longer be correctly synced to the remote.
>
> When shallow mode is used on *existing* branch or tag in a
> mirror-mode or single-branch repository, new commits are fetched
> as in single-branch mode. When shallow mode is used on *new*
> branch or tag, the commits are fetched with '--depth 1' and the
> clone is marked 'shallow'.
>
>

I am not sure if I understand this correctly, but it sounds like it
would be safer to rm -rf the old checkout completely when switching
modes? I wouldn't expect people to randomly switch around, so why bother.

Anyway, sounds like a plan.
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