Re: [PATCH] bundle-uri: refresh packed_git if unbundle succeed

> When using the bundle-uri mechanism with a bundle list containing
> multiple interrelated bundles, we encountered a bug where tips from
> downloaded bundles were not being discovered, resulting in rather slow
> clones. This was particularly problematic when employing the heuristic
> `creationTokens`.
> 
> And this is easy to reproduce. Suppose we have a repository with a
> single branch `main` pointing to commit `A`, firstly we create a base
> bundle with
> 
>   git bundle create base.bundle main
> 
> Then let's add a new commit `B` on top of `A`, so that an incremental
> bundle for `main` can be created with
> 
>   git bundle create incr.bundle A..main
> 
> Now we can generate a bundle list with the following content:
> 
>   [bundle]
>       version = 1
>       mode = all
>       heuristic = creationToken
> 
>   [bundle "base"]
>       uri = base.bundle
>       creationToken = 1
> 
>   [bundle "incr"]
>       uri = incr.bundle
>       creationToken = 2
> 
> A fresh clone with the bundle list above would give the expected
> `refs/bundles/main` pointing at `B` in new repository, in other words we
> already had everything locally from the bundles, but git would still
> download everything from server as if we got nothing.
> 
> So why the `refs/bundles/main` is not discovered? After some digging I
> found that:
> 
> 1. when unbundling a downloaded bundle, a `verify_bundle` is called to
>    check its prerequisites if any. The verify procedure would find oids
>    so `packed_git` is initialized.
> 
> 2. after unbundled all bundles, we would enter `do_fetch_pack_v2`,
>    during which `mark_complete_and_common_ref` and `mark_tips` would
>    find oids with `OBJECT_INFO_QUICK` flag set, so no new packs would be
>    enlisted if `packed_git` has already initialized in 1.

> Signed-off-by: Xing Xin <xingxin.xx@bytedance.com>
> ---
>     bundle-uri: refresh packed_git if unbundle succeed
> 
> Published-As: https://github.com/gitgitgadget/git/releases/tag/pr-1730%2Fblanet%2Fxx%2Fbundle-uri-bug-using-bundle-list-v1
> Fetch-It-Via: git fetch https://github.com/gitgitgadget/git pr-1730/blanet/xx/bundle-uri-bug-using-bundle-list-v1
> Pull-Request: https://github.com/gitgitgadget/git/pull/1730
> 
>  bundle-uri.c                |   3 +
>  t/t5558-clone-bundle-uri.sh | 129 ++++++++++++++++++++++++++++++++++++
>  2 files changed, 132 insertions(+)
> 
> diff --git a/bundle-uri.c b/bundle-uri.c
> index ca32050a78f..2b9d36cfd8e 100644
> --- a/bundle-uri.c
> +++ b/bundle-uri.c
> @@ -7,6 +7,7 @@
>  #include "refs.h"
>  #include "run-command.h"
>  #include "hashmap.h"
> +#include "packfile.h"
>  #include "pkt-line.h"
>  #include "config.h"
>  #include "remote.h"
> @@ -376,6 +377,8 @@ static int unbundle_from_file(struct repository *r, const char *file)
>  			       VERIFY_BUNDLE_QUIET)))
>  		return 1;
>  
> +	reprepare_packed_git(r);
> +