[GSoC] extensions.partialClone and promisor remote fetch order

[GSoC] extensions.partialClone and promisor remote fetch order

[Lorenzo Pegorari]

Hi everyone. In the past weeks I deeply studied the documentation
regarding the GSoC'26 idea "Implement promisor remote fetch ordering". I
am preparing a proposal that is as detailed as possible, and that tries
to answer to as many questions as possible. I am also experimenting a
lot with multiple promisor remotes configurations, and creating some
examples that I will showcase in my proposal.


I have a question regarding the interaction between the config
"extensions.partialClone" and a possible fetch ordering mechanism:
 * from my understanding, and from my personal tests, it looks like
   "extensions.partialClone" is not essential when working with multiple
   promisor remotes. Having these promisor remotes setted up with
   "remote.<name>.promisor" and "remote.<name>.partialCloneFilter" seems
   sufficient. In this case, the promisor remotes will be tried one
   after the other, in the order in which they appear in the config.
 * if "extensions.partialClone" is present, then the promisor remote
   configured using the "extensions.partialClone" config var will be the
   last one tried when fetching an object.

1. is what I explained correct?
2. when the fetch ordering mechanism will be added, this config var will
   not be useful anymore. How should it be handled? It probably can't
   just be removed, so the fetch ordering mechanism should be flexible
   enough to handle a situation where "extensions.partialClone" is
   present, correct?


Thanks,
Lorenzo

Re: [GSoC] extensions.partialClone and promisor remote fetch order

[Lorenzo Pegorari]

On Sat, Mar 07, 2026 at 10:28:33AM +0100, Lorenzo Pegorari wrote:
> Hi everyone. In the past weeks I deeply studied the documentation
> regarding the GSoC'26 idea "Implement promisor remote fetch ordering". I
> am preparing a proposal that is as detailed as possible, and that tries
> to answer to as many questions as possible. I am also experimenting a
> lot with multiple promisor remotes configurations, and creating some
> examples that I will showcase in my proposal.
> 
> 
> I have a question regarding the interaction between the config
> "extensions.partialClone" and a possible fetch ordering mechanism:
>  * from my understanding, and from my personal tests, it looks like
>    "extensions.partialClone" is not essential when working with multiple
>    promisor remotes. Having these promisor remotes setted up with
>    "remote.<name>.promisor" and "remote.<name>.partialCloneFilter" seems
>    sufficient. In this case, the promisor remotes will be tried one
>    after the other, in the order in which they appear in the config.
>  * if "extensions.partialClone" is present, then the promisor remote
>    configured using the "extensions.partialClone" config var will be the
>    last one tried when fetching an object.
> 
> 1. is what I explained correct?
> 2. when the fetch ordering mechanism will be added, this config var will
>    not be useful anymore. How should it be handled? It probably can't
>    just be removed, so the fetch ordering mechanism should be flexible
>    enough to handle a situation where "extensions.partialClone" is
>    present, correct?
> 
> 
> Thanks,
> Lorenzo

Also, I see that "extensions.partialClone" is already necessary "to
prevent older versions of git from failing mid-operation because of
missing objects that they cannot handle".

This is one of the last issues that I still have to iron out before I
can send a satisfactory proposal draft.

[1]: https://git-scm.com/docs/git-config#Documentation/git-config.txt-partialClone
[2]: https://git-scm.com/docs/git-config#Documentation/git-config.txt-partialClone

Re: [GSoC] extensions.partialClone and promisor remote fetch order

[Christian Couder]

Hi Lorenzo,

On Sat, Mar 7, 2026 at 10:28 AM Lorenzo Pegorari
<lorenzo.pegorari2002@gmail.com> wrote:
>
> Hi everyone. In the past weeks I deeply studied the documentation
> regarding the GSoC'26 idea "Implement promisor remote fetch ordering". I
> am preparing a proposal that is as detailed as possible, and that tries
> to answer to as many questions as possible. I am also experimenting a
> lot with multiple promisor remotes configurations, and creating some
> examples that I will showcase in my proposal.

Thanks for your interest in Git and this project.

> I have a question regarding the interaction between the config
> "extensions.partialClone" and a possible fetch ordering mechanism:
>  * from my understanding, and from my personal tests, it looks like
>    "extensions.partialClone" is not essential when working with multiple
>    promisor remotes. Having these promisor remotes setted up with
>    "remote.<name>.promisor" and "remote.<name>.partialCloneFilter" seems
>    sufficient. In this case, the promisor remotes will be tried one
>    after the other, in the order in which they appear in the config.
>  * if "extensions.partialClone" is present, then the promisor remote
>    configured using the "extensions.partialClone" config var will be the
>    last one tried when fetching an object.
>
> 1. is what I explained correct?

Yes, I think so. The "Using many promisor remotes" section of
"Documentation/technical/partial-clone.adoc" seems to agree with what
you say.

> 2. when the fetch ordering mechanism will be added, this config var will
>    not be useful anymore. How should it be handled? It probably can't
>    just be removed, so the fetch ordering mechanism should be flexible
>    enough to handle a situation where "extensions.partialClone" is
>    present, correct?

Yes, for backward compatibility, it's better to have things work as
they used to when the new ordering mechanism is not used.

Re: [GSoC] extensions.partialClone and promisor remote fetch order

[Lorenzo Pegorari]

On Mon, Mar 09, 2026 at 02:40:42PM +0100, Christian Couder wrote:
> Hi Lorenzo,
> 
> On Sat, Mar 7, 2026 at 10:28 AM Lorenzo Pegorari
> <lorenzo.pegorari2002@gmail.com> wrote:
> >
> > Hi everyone. In the past weeks I deeply studied the documentation
> > regarding the GSoC'26 idea "Implement promisor remote fetch ordering". I
> > am preparing a proposal that is as detailed as possible, and that tries
> > to answer to as many questions as possible. I am also experimenting a
> > lot with multiple promisor remotes configurations, and creating some
> > examples that I will showcase in my proposal.
> 
> Thanks for your interest in Git and this project.
> 
> > I have a question regarding the interaction between the config
> > "extensions.partialClone" and a possible fetch ordering mechanism:
> >  * from my understanding, and from my personal tests, it looks like
> >    "extensions.partialClone" is not essential when working with multiple
> >    promisor remotes. Having these promisor remotes setted up with
> >    "remote.<name>.promisor" and "remote.<name>.partialCloneFilter" seems
> >    sufficient. In this case, the promisor remotes will be tried one
> >    after the other, in the order in which they appear in the config.
> >  * if "extensions.partialClone" is present, then the promisor remote
> >    configured using the "extensions.partialClone" config var will be the
> >    last one tried when fetching an object.
> >
> > 1. is what I explained correct?
> 
> Yes, I think so. The "Using many promisor remotes" section of
> "Documentation/technical/partial-clone.adoc" seems to agree with what
> you say.
> 
> > 2. when the fetch ordering mechanism will be added, this config var will
> >    not be useful anymore. How should it be handled? It probably can't
> >    just be removed, so the fetch ordering mechanism should be flexible
> >    enough to handle a situation where "extensions.partialClone" is
> >    present, correct?
> 
> Yes, for backward compatibility, it's better to have things work as
> they used to when the new ordering mechanism is not used.

Exactly what I thought. Thanks for the clarifications Christian!

I just sent my GSoC'26 proposal, where I took into consideration this
discussion:
https://lore.kernel.org/git/abBh__zmlWXY-yjI@lorenzo-VM/


Lorenzo