Re: Possible to unshallow or deepen based on local objects?

[Mark Rushakoff <mark@influxdata.com>]

On Fri, Jul 26, 2019 at 11:43 AM Mark Rushakoff <mark@influxdata.com> wrote:
>
> I am building some CI tooling, and I am working with a large-ish repository, so
> I am trying to start with a shallow clone of the repository and deepen it on
> demand. I am finding it very difficult to correctly switch between fetch
> --depth and fetch --deepen.
>
> I am looking for a way to "recover" from a fetch --depth call that made my
> history shallower than before. Ultimately, I may take a different approach to
> just work around this altogether, but I thought I'd ask here first.
>
> In particular, if there is history like this:
>
> A --- B --- C --- D --- E --- F
>        \                 \
>          ---------------- G
> And my shallow history includes D..F, then I believe I am limited in my options
> for fetching G:
>
> - If I do a plain fetch of G, or if I use --deepen, then I pull in A and all of
>   its history, which I don't strictly need or want yet.
> - If I know G's parent is B, and I fetch --depth=1, then (I think) I will see
>   B, E, F, and G, effectively losing sight of D
>
> As a more contrived example, suppose I have a shallow clone of a repository:
>
> bash-3.2$ git clone --depth=4 -q git@github.com:git/git.git
> bash-3.2$ cd git
> bash-3.2$ git log --format='%h %d'
> 3034dab  (HEAD -> master, origin/master, origin/HEAD)
> 98e06de
> 352253a
> 4098130  (grafted)
> 7b974e3
> df63c2e
> 75ce486  (grafted)
> 70b39fb  (grafted)
> afc3bf6  (grafted)
> bash-3.2$ cat .git/shallow
> 409813088ad55ae4a60f55412f6b5ba6a89d89e7
> 70b39fbede78313656e8a6bd9b38b238ab10db2f
> 75ce48674889df6a2bb493fb5d6bef0ef60ca7ae
> afc3bf6eb13d9fc489b569164819cff44db8ac17
>
> And then suppose I fetch with depth smaller than before:
>
> bash-3.2$ git fetch --depth=1 -q
> bash-3.2$ git log --format='%h %d'
> 3034dab  (grafted, HEAD -> master, origin/master, origin/HEAD)
> bash-3.2$ cat .git/shallow
> 3034dab9ed6b11970a53099a7b3ca981f1461365
> 409813088ad55ae4a60f55412f6b5ba6a89d89e7
> 70b39fbede78313656e8a6bd9b38b238ab10db2f
> 75ce48674889df6a2bb493fb5d6bef0ef60ca7ae
> afc3bf6eb13d9fc489b569164819cff44db8ac17
>
> I can still see the commits I had before the --depth=1 fetch:
>
> bash-3.2$ git log -1 --format=oneline 75ce486
> 75ce48674889df6a2bb493fb5d6bef0ef60ca7ae (grafted) Merge branch
> 'di/readme-markup-fix'
>
> Short of looking through .git/shallow and removing each entry whose parents I
> can resolve, is there a built-in command to "unshallow based on local objects"?
> I have tried many web search terms, I have looked through the docs for many
> low-level git commands, I have tried variations of "git fetch .", and I am
> stumped.

I've run into another flavor of this problem now.

I have a shallow clone of a repository. Then sometime later, I obtain a bundle
containing full history.

I thought I could use git fetch --unshallow /path/to/repo.bundle
mybranch:mybranch, but I've found that git does not support shallow fetches
from a bundle and that unshallow is actually an alias for --depth=2147483647 in
4dcb167fc3 (fetch: add --unshallow for turning shallow repo into complete one,
2013-01-11).

If I do a plain fetch from the bundle, I can manually modify .git/shallow to
"unshallow" my repository like the previous email in this thread. But what I
think I still want here is a way to tell git "here are all the objects I have;
update the shallow boundaries accordingly."