On 15-09-2022 19:43, Csepp wrote:
> Could we store the offsets of references somewhere at build time?

I now remember that idea, I forgot about that one.

My answer: I don't see why not, maybe by adding a phase to 
%standard-phases (at the very end, to avoid it becoming invalid) that 
saves it in, say, OUTPUT/.graft-offsets?

That would avoid grafting files that don't even have any references, 
where a copy-file (maybe using copy_file_range or such when available)
would suffice.

Fallbacks might be necessary (not every store item is constructed from a 
package), but it all sounds doable and efficient.  Also the union could 
needs to be modified to ignore the .graft-offsets of the union'ed things.

Greetings,
Maxime.