Re: [RFC PATCH 05/35] fast-forward: add advice for novices

> It doesn't hurt showing it on `git merge --ff-only` too.
>
> Signed-off-by: Felipe Contreras <felipe.contreras@gmail.com>
> ---
>  advice.c        | 11 +++++++++++
>  advice.h        |  1 +
>  builtin/merge.c |  4 +++-
>  3 files changed, 15 insertions(+), 1 deletion(-)
>
> diff --git a/advice.c b/advice.c
> index 0b9c89c48a..8f068c8be9 100644
> --- a/advice.c
> +++ b/advice.c
> @@ -326,3 +326,14 @@ void detach_advice(const char *new_name)
>  
>  	fprintf(stderr, fmt, new_name);
>  }
> +
> +void diverging_advice(void)
> +{
> +	advise(_("Diverging branches can't be fast-forwarded, you need to either:\n"
> +		"\n"
> +		"\tgit merge\n"
> +		"\n"
> +		"or:\n"
> +		"\n"
> +		"\tgit rebase\n"));
> +}
> diff --git a/advice.h b/advice.h
> index bd26c385d0..6ce967c962 100644
> --- a/advice.h
> +++ b/advice.h
> @@ -97,5 +97,6 @@ void NORETURN die_resolve_conflict(const char *me);
>  void NORETURN die_conclude_merge(void);
>  void advise_on_updating_sparse_paths(struct string_list *pathspec_list);
>  void detach_advice(const char *new_name);
> +void diverging_advice(void);
>  
>  #endif /* ADVICE_H */
> diff --git a/builtin/merge.c b/builtin/merge.c
> index e396943d37..1836f98f82 100644
> --- a/builtin/merge.c
> +++ b/builtin/merge.c
> @@ -1625,8 +1625,10 @@ static int merge_common(int argc, const char **argv, const char *prefix,
>  		}
>  	}
>  
> -	if (fast_forward == FF_ONLY)
> +	if (fast_forward == FF_ONLY) {
> +		diverging_advice();
>  		die(_("unable to fast-forward"));
> +	}
>  
>  	if (autostash)
>  		create_autostash(the_repository,