Re: [bitbake-devel] [PATCH] fetch/git: add reference option

["Daniel Walker (danielwa)" <danielwa@cisco.com>]

On Fri, Jun 26, 2026 at 03:56:02PM -0400, Bruce Ashfield wrote:
> On Fri, Jun 26, 2026 at 3:10 PM Daniel Walker via lists.openembedded.org
> <danielwa=cisco.com@lists.openembedded.org> wrote:
> 
> > Adds a option to the git fetcher which can be used to specify a local
> > reference for a given SRC_URI. Which is then fed into the clone command
> > as "--reference-if-able" which make the option fault tolerant if the
> > directory doesn't exist.
> >
> 
> We tried this in the past (maybe 10 years ago now) to chunk the
> kernel into different sets of blobs and do a set of references for
> optimal sharing, repacking, etc.
> 
> In the end, it was discarded as unnecessary complexity.
> 
> I'm still of the opinion that is the case. What problem is this solving
> that justifies the complexity ?
> 
> the patch doesn't show a real world use case, what the SRC_URI
> would look like, where the referenced clone would be, what would
> happen if the referenced repository was somehow cleaned, or
> any number of different interactions (what happens if shallow is
> specified, etc, etc).
> 

At Cisco we have settings which modify the SRC_URI to become the local repo.

For example,

KERNEL_REPO:pn-linux-cisco = "git:///local/git/cache/;protocol=file"

This works to use a local cache of the repo, but it messes up the state cache so
objects can't be used by others.

If we use "--reference-if-able" then the git host and location remains the same, but the
local copy can speed up the clone.

For down stream users, like Cisco, who work in a complex environment it's
helpful to have flexibility.

The reference is not harmful that I know of, it's only used if it can be used.

Daniel