Re: [PATCH v2] fetch-pack: show clearer error message upon ERR

> Currently, fetch-pack prints a confusing error message ("expected
> ACK/NAK") when the server it's communicating with sends a pkt-line
> starting with "ERR".  Replace it with a less confusing error message.
>
> Also update the documentation describing the fetch-pack/upload-pack
> protocol (pack-protocol.txt) to indicate that "ERR" can be sent in the
> place of "ACK" or "NAK". In practice, this has been done for quite some
> time by other Git implementations (e.g. JGit sends "want $id not valid")
> and by Git itself (since commit bdb31ea: "upload-pack: report "not our
> ref" to client", 2017-02-23) whenever a "want" line references an object
> that it does not have. (This is uncommon, but can happen if a repository
> is garbage-collected during a negotiation.)
>
> Signed-off-by: Jonathan Tan <jonathantanmy@google.com>
> ---
>
> Changes from v1:
>  - used jrneider's suggested change to error message
>  - added documentation about "ERR" in protocol
>  - updated commit message to explain documentation change
>
>  Documentation/technical/pack-protocol.txt | 7 ++++++-
>  fetch-pack.c                              | 2 ++
>  2 files changed, 8 insertions(+), 1 deletion(-)