Subject: Re: [PATCH v3 4/6] xdiff/xdl_cleanup_records: make limits more clear

From: Junio C Hamano <[email-masked]>
Date: Fri, 27 Mar 2026 14:09:47 -0700

"Ezekiel Newren via GitGitGadget" <[email-masked]> writes:

> From: Ezekiel Newren <[email-masked]>
>
> Make the handling of per-file limits and the minimal-case clearer.
>   * Use explicit per-file limit variables (mlim1, mlim2) and initialize
>     them.
>   * The additional condition `!need_min` is redudant now, remove it.
> Best viewed with --color-words.
>
> Signed-off-by: Ezekiel Newren <[email-masked]>
> ---
>  xdiff/xprepare.c | 19 ++++++++++++-------
>  1 file changed, 12 insertions(+), 7 deletions(-)

t4071 and t8015 do not like this step, even though they are happy
with 1-3/6 applied.

> diff --git a/xdiff/xprepare.c b/xdiff/xprepare.c
> index 386668a92d..2cf1f8d1a8 100644
> --- a/xdiff/xprepare.c
> +++ b/xdiff/xprepare.c
> @@ -268,7 +268,7 @@ static bool xdl_clean_mmatch(uint8_t const *action, ptrdiff_t i, ptrdiff_t s, pt
>   * might be potentially discarded if they appear in a run of discardable.
>   */
>  static int xdl_cleanup_records(xdlclassifier_t *cf, xdfile_t *xdf1, xdfile_t *xdf2) {
> -	ptrdiff_t i, nm, mlim;
> +	ptrdiff_t i, nm, mlim1, mlim2;
>  	xdlclass_t *rcrec;
>  	uint8_t *action1 = NULL, *action2 = NULL;
>  	bool need_min = !!(cf->flags & XDF_NEED_MINIMAL);
> @@ -287,25 +287,30 @@ static int xdl_cleanup_records(xdlclassifier_t *cf, xdfile_t *xdf1, xdfile_t *xd
>  		goto cleanup;
>  	}
>  
> +	if (need_min) {
> +		/* i.e. infinity */
> +		mlim1 = SIZE_MAX;
> +		mlim2 = SIZE_MAX;
> +	} else {
> +		mlim1 = XDL_MIN(xdl_bogosqrt(xdf1->nrec), XDL_MAX_EQLIMIT);
> +		mlim2 = XDL_MIN(xdl_bogosqrt(xdf2->nrec), XDL_MAX_EQLIMIT);
> +	}
> +
>  	/*
>  	 * Initialize temporary arrays with DISCARD, KEEP, or INVESTIGATE.
>  	 */
> -	if ((mlim = (long)xdl_bogosqrt((uint64_t)xdf1->nrec)) > XDL_MAX_EQLIMIT)
> -		mlim = XDL_MAX_EQLIMIT;
>  	for (i = xdf1->dstart; i <= xdf1->dend; i++) {
>  		size_t mph1 = xdf1->recs[i].minimal_perfect_hash;
>  		rcrec = cf->rcrecs[mph1];
>  		nm = rcrec ? rcrec->len2 : 0;
> -		action1[i] = (nm == 0) ? DISCARD: (nm >= mlim && !need_min) ? INVESTIGATE: KEEP;
> +		action1[i] = (nm == 0) ? DISCARD: nm >= mlim1 ? INVESTIGATE: KEEP;
>  	}
>  
> -	if ((mlim = (long)xdl_bogosqrt((uint64_t)xdf2->nrec)) > XDL_MAX_EQLIMIT)
> -		mlim = XDL_MAX_EQLIMIT;
>  	for (i = xdf2->dstart; i <= xdf2->dend; i++) {
>  		size_t mph2 = xdf2->recs[i].minimal_perfect_hash;
>  		rcrec = cf->rcrecs[mph2];
>  		nm = rcrec ? rcrec->len1 : 0;
> -		action2[i] = (nm == 0) ? DISCARD: (nm >= mlim && !need_min) ? INVESTIGATE: KEEP;
> +		action2[i] = (nm == 0) ? DISCARD: nm >= mlim2 ? INVESTIGATE: KEEP;
>  	}
>  
>  	/*