Re: [PATCH 5/9] refs: avoid duplicate running of the reference-transaction hook

From: Jiang Xin <worldhello.net@gmail.com>
Date: Aug 5, 2022, 01:41 UTC
Message-ID: <CANYiYbFw71bX827akAG87RSKOozPk313Hoe573O9dQ65_U6sLQ@mail.gmail.com>
In-Reply-To: <CAJDSCnOFSnhOU06UHF6T9RT31Gq56BhJn5fQ4_ys2ERrN1stSw@mail.gmail.com>

On Tue, Aug 2, 2022 at 8:18 PM Michael Heemskerk <mheemskerk@atlassian.com> wrote:

Show 21 quoted lines

>
> On Fri, Jul 29, 2022 at 12:20 PM Jiang Xin <worldhello.net@gmail.com> wrote:
> >
> > From: Jiang Xin <zhiyou.jx@alibaba-inc.com>
> >
> > If there are references to be deleted in a transaction, we should remove
> > each reference from both loose references and the "packed-refs" file.
> > The "reference-transaction" hook will run twice, once for the primary
> > ref-store (loose references), and another for the second ref-store (i.e.
> > packed ref-store).
> >
> > To avoid duplicate running of the "reference-trancaction" hook, we pass
> > a special "hook-flags" parameter to initialize the second ref-store.
> > The "REF_TRANSACTION_RUN_PREPARED_HOOK" bit is preserved for the
> > transaction of the second ref-store because we may still want to call
> > command "reference-trancaction prepared" for some pre-checks, such as
> > terminate unwanted transaction for the "packed-refs" file.
>
> Can you elaborate on the rationale for continuing to invoke the "prepared"
> reference-transaction hook for the "packed-refs" file? Did you have a specific
> type of check in mind?

Use "reference-transaction prepared" hook command, we can implement write lock for repositories. We can create a lock file (e.g. "site.lock") inside a repository or in a parent directory to disable write operations for one repository, a group of repositories or all repositories. The magic is in the "reference-transaction prepared" hook command. As a transaction may be triggered twice, one for packed-refs, and one for loose-refs, we should make sure the "reference-transaction prepared" command must run for both transactions on different ref-stores.

BTW, I'm on vacation for the next few days and I will pick up this topic next week.

-- Jiang Xin