Jonathan Tan <jonathantanmy@xxxxxxxxxx> writes: >> This may reject to clone from a shallow repository, but at this >> point the bulk of the tranfer from the origin repository has already >> happened, no? Rejecting after transferring many megabytes feels a >> bit too late. That is one of the reasons why I kept hinting that >> the transport layer needs to be taught an option to reject talking >> to a shallow counterpart if we want to add this feature [*1*]. > > Extending the transport layer in this way might not be too difficult in > the case of native (SSH, git://) protocols and using protocol v0, since > handshake() in transport.c (called indirectly from > transport_get_remote_refs()) writes shallow information to a data > structure that we could potentially expose for the caller to use (before > it calls transport_fetch_refs(). I couldn't see how remote-using > protocols (e.g. HTTP) communicate shallow information, though > (remote-curl.c seems to just keep it for itself), so that will be a more > difficult task. And of course there's the matter of protocol v2, which I > discuss below. > >> [Footnote] >> >> *1* Looking at Documentation/technical/pack-protocol.txt, "git >> fetch" seem to learn if the repository is shallow immediately >> upon contacting "upload-pack" during the Reference Discovery >> phase (we'd see 'shallow' packets if they are shallow). I >> suspect that the right solution would be to teach the codepath >> on the "git fetch" side that accepts, parses, and acts on this >> packet to optionally stop communication and error out when the >> caller asks not to talk with a shallow repository. > > This is true with protocol v0, but protocol v2 bundles all shallow > information (whether coming from the fact that the remote is shallow or > the fact that the fetcher specified --depth etc.) and sends them > together with the packfile. It may be possible to stop packfile download > (saving bandwidth on the client side, at least) once such information is > returned, though. So in short, the "we do not want to clone from a shallow upstream" would not be possible to implement sensibly without significantly cleaning up the protocol layers first, which makes the whole thing pretty much moot. Thanks for a review and insight.
