On Mon, Oct 01, 2018 at 09:45:52AM -0400, Ben Peart wrote:
> From: Ben Peart <benpeart@xxxxxxxxxxxxx>
>
> The End of Index Entry (EOIE) is used to locate the end of the variable
> length index entries and the beginning of the extensions. Code can take
> advantage of this to quickly locate the index extensions without having
> to parse through all of the index entries.
>
> Because it must be able to be loaded before the variable length cache
> entries and other index extensions, this extension must be written last.
> The signature for this extension is { 'E', 'O', 'I', 'E' }.
>
> The extension consists of:
>
> - 32-bit offset to the end of the index entries
>
> - 160-bit SHA-1 over the extension types and their sizes (but not
> their contents). E.g. if we have "TREE" extension that is N-bytes
> long, "REUC" extension that is M-bytes long, followed by "EOIE",
> then the hash would be:
>
> SHA-1("TREE" + <binary representation of N> +
> "REUC" + <binary representation of M>)
>
> Signed-off-by: Ben Peart <peartben@xxxxxxxxx>
I think the commit message should explicitly mention that this this
extension
- will always be written and why,
- but is optional, so other Git implementations not supporting it will
have no troubles reading the index,
- and that it is written even to the shared index and why, and that
because of this the index checksums in t1700 had to be updated.
