• Jonathan Tan's avatar
    fetch-pack: do not take shallow lock unnecessarily · bd0b42ae
    Jonathan Tan authored
    When fetching using protocol v2, the remote may send a "shallow-info"
    section if the client is shallow. If so, Git as the client currently
    takes the shallow file lock, even if the "shallow-info" section is
    empty.
    
    This is not a problem except that Git does not support taking the
    shallow file lock after modifying the shallow file, because
    is_repository_shallow() stores information that is never cleared. And
    this take-after-modify occurs when Git does a tag-following fetch from a
    shallow repository on a transport that does not support tag following
    (since in this case, 2 fetches are performed).
    
    To solve this issue, take the shallow file lock (and perform all other
    shallow processing) only if the "shallow-info" section is non-empty;
    otherwise, behave as if it were empty.
    
    A full solution (probably, ensuring that any action of committing
    shallow file locks also includes clearing the information stored by
    is_repository_shallow()) would solve the issue without need for this
    patch, but this patch is independently useful (as an optimization to
    prevent writing a file in an unnecessary case), hence why I wrote it. I
    have included a NEEDSWORK outlining the full solution.
    Signed-off-by: 's avatarJonathan Tan <jonathantanmy@google.com>
    Signed-off-by: 's avatarJunio C Hamano <gitster@pobox.com>
    bd0b42ae
shallow.c 21.2 KB