Re: [PATCH v12 7/8] fetch: set remote/HEAD if it does not exist

> If the user has remote/HEAD set already and it looks like it has changed
> on the server, then print a message, otherwise set it if we can.
> Silently pass if the user already has the same remote/HEAD set as
> reported by the server or if we encounter any errors along the way.
>
> Signed-off-by: Bence Ferdinandy <bence@ferdinandy.com>
> ---
>
> Notes:
>     v3: - does not rely on remote set-head anymore so it only authenticates
>         once
>         - uses the new REF_CREATE_ONLY to atomically check if the ref exists
>           and only write it if it doesn't
>         - in all other cases the maximum it does is print a warning
>
>     v4: - instead of the discarded REF_CREATE_ONLY, it uses the existing,
>           but updated transaction api to request a silent create only
>         - it now uses the atomic before_target to determine reporting
>         - refactored for legibility
>
>     v5: - instead of printing a not too useful message, it now fails
>           silently, this in line with the objective to only set up
>           remote/HEAD automatically if the right thing is trivial, for
>           everything else there is remote set-head
>         - fixed all failing tests
>         - added two new tests, one for checking if remote/HEAD is set to the
>           correct one, and one to test that we do not override remote/HEAD
>           if it has changed on the server from what we have locally
>
>     v6: - fixed style issues and unintended extra empty line
>         - updated function call with bool to int from previous patch's
>           change
>         - removed calls to error(...) inherited from builtin/remote.c so we
>           actually fail silently
>         - set the test for remote set-head --auto to the correct value here,
>           which was previously erronously set in the remote set-head patch
>
>     v7: - no change
>
>     v8: - changed logmsg in call to refs_update_symref from "remote
>           set-head" to "fetch"
>
>     v9: - follow through with refs_update_symref_extended
>         - fix test errors uncovered by the new patch
>
>     v10: no change
>
>     v11: fixed some memory leaks
>
>     v12: no change