Re: [RFC/PATCH] rename: warn user when we have turned off rename detection

[Junio C Hamano <gitster@pobox.com>]

Jeff King <peff@peff.net> writes:

> Signed-off-by: Jeff King <peff@peff.net>
> ---
> This was another patch from late in the freeze period. It was in
> response to a user getting confused about why rename detection wasn't
> happening in a large merge. Is it appropriate to print this for every
> rename we try? Or should it just be for merges?
>
> Perhaps we should also bump the default limit from 100, which I think
> was just arbitrarily chosen.
> ...
> +	if ((num_create > rename_limit && num_src > rename_limit) ||
> +	    (num_create * num_src > rename_limit * rename_limit)) {
> +		warning("too many files, skipping inexact rename detection");
>  		goto cleanup;
> +	}
> 
>  	mx = xmalloc(sizeof(*mx) * num_create * num_src);
>  	for (dst_cnt = i = 0; i < rename_dst_nr; i++) {

This reminds me of the 6d24ad9 (Optimize rename detection for a huge diff)
topic that reduces the above allocation greatly.  Some benching with the
patch may prove useful to establish much higher limits, I suspect.