Re: [RFC PATCH 1/1] rebase --onto: Skip previously applied commits

> When rebase is used with '--onto <newbase>', the patches that might have
> been already applied on <newbase> are not detected, unless they resolve
> to an empty commit. When the related files contain additional changes
> merged, the rebase operation fails due to conflicts that require manual
> intervention.
>
> Ensure the '--onto' variant behaviour is consistent with the common
> rebase by dropping the already applied commits on the target branch.
>
> Note the current behavior is still reachable by using the
> '--reapply-cherry-picks' flag.
>
> Signed-off-by: Cristian Ciocaltea <cristian.ciocaltea@collabora.com>
> ---
>  builtin/rebase.c | 6 +++++-
>  1 file changed, 5 insertions(+), 1 deletion(-)
>
> diff --git a/builtin/rebase.c b/builtin/rebase.c
> index b22768ca5b9f..2907c6db5cce 100644
> --- a/builtin/rebase.c
> +++ b/builtin/rebase.c
> @@ -1659,8 +1659,12 @@ int cmd_rebase(int argc, const char **argv, const char *prefix)
>  		strbuf_addstr(&buf, "...");
>  		strbuf_addstr(&buf, branch_name);
>  		options.onto_name = xstrdup(buf.buf);
> -	} else if (!options.onto_name)
> +	} else if (!options.onto_name) {
>  		options.onto_name = options.upstream_name;
> +	} else if (options.upstream) {
> +		options.restrict_revision = options.upstream;
> +		options.upstream = NULL;
> +	}
>  	if (strstr(options.onto_name, "...")) {
>  		if (get_oid_mb(options.onto_name, &branch_base) < 0) {
>  			if (keep_base)