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From: Junio C Hamano <gitster@pobox.com>
To: "Michał Kępień" <michal@isc.org>
Cc: git@vger.kernel.org
Subject: Re: [PATCH v2 1/3] merge-base, xdiff: zero out xpparam_t structures
Date: Mon, 12 Oct 2020 12:52:59 -0700	[thread overview]
Message-ID: <xmqqsgajnrvo.fsf@gitster.c.googlers.com> (raw)
In-Reply-To: <20201012091751.19594-2-michal@isc.org> (=?utf-8?B?Ik1pY2hh?= =?utf-8?B?xYIgS8SZcGllxYQiJ3M=?= message of "Mon, 12 Oct 2020 11:17:49 +0200")

Michał Kępień <michal@isc.org> writes:

> diff --git a/builtin/merge-tree.c b/builtin/merge-tree.c
> index e72714a5a8..de8520778d 100644
> --- a/builtin/merge-tree.c
> +++ b/builtin/merge-tree.c
> @@ -109,6 +109,7 @@ static void show_diff(struct merge_list *entry)
>  	xdemitconf_t xecfg;
>  	xdemitcb_t ecb;
>  
> +	memset(&xpp, 0, sizeof(xpp));
>  	xpp.flags = 0;
>  	memset(&xecfg, 0, sizeof(xecfg));
>  	xecfg.ctxlen = 3;

The existing "xpp.flags=0" can then go away, and as Dscho hinted,

	xpparam_t xpp = {
		.flags = 0,
	};

may also be a valid way to write this.  What it says is that we want
the entirety of xpp to be reasonably initialized, but we do care
that its .flags field to be exactly zero.

> diff --git a/xdiff/xhistogram.c b/xdiff/xhistogram.c
> index c7b35a9667..e694bfd9e3 100644
> --- a/xdiff/xhistogram.c
> +++ b/xdiff/xhistogram.c
> @@ -235,6 +235,8 @@ static int fall_back_to_classic_diff(xpparam_t const *xpp, xdfenv_t *env,
>  		int line1, int count1, int line2, int count2)
>  {
>  	xpparam_t xpparam;
> +
> +	memset(&xpparam, 0, sizeof(xpparam));
>  	xpparam.flags = xpp->flags & ~XDF_DIFF_ALGORITHM_MASK;

Likewise.  Giving an initializer to the local variable def, e.g.

	xpparam_t xpparam = {
		.flags = xpp->flags & ~XDF_DIFF_ALGORITHM_MASK,
	};

would allow us to lose one line.

>  	return xdl_fall_back_diff(env, &xpparam,
> diff --git a/xdiff/xpatience.c b/xdiff/xpatience.c
> index 3c5601b602..20699a6f60 100644
> --- a/xdiff/xpatience.c
> +++ b/xdiff/xpatience.c
> @@ -318,6 +318,8 @@ static int fall_back_to_classic_diff(struct hashmap *map,
>  		int line1, int count1, int line2, int count2)
>  {
>  	xpparam_t xpp;
> +
> +	memset(&xpp, 0, sizeof(xpp));
>  	xpp.flags = map->xpp->flags & ~XDF_DIFF_ALGORITHM_MASK;

Likewise.

>  	return xdl_fall_back_diff(map->env, &xpp,

But the patch is good as-is, given especially the way how xecfg is
cleared the same way in builtin/merge-tree.c::show_diff().

Will queue.  Thanks.

  parent reply	other threads:[~2020-10-12 19:53 UTC|newest]

Thread overview: 57+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-10-01 12:06 [PATCH 0/2] diff: add -I<regex> that ignores matching changes Michał Kępień
2020-10-01 12:06 ` [PATCH 1/2] " Michał Kępień
2020-10-01 18:21   ` Junio C Hamano
2020-10-07 19:48     ` Michał Kępień
2020-10-07 20:08       ` Junio C Hamano
2020-10-01 12:06 ` [PATCH 2/2] t: add -I<regex> tests Michał Kępień
2020-10-01 17:02 ` [PATCH 0/2] diff: add -I<regex> that ignores matching changes Junio C Hamano
2020-10-12  9:17 ` [PATCH v2 0/3] " Michał Kępień
2020-10-12  9:17   ` [PATCH v2 1/3] merge-base, xdiff: zero out xpparam_t structures Michał Kępień
2020-10-12 11:14     ` Johannes Schindelin
2020-10-12 17:09       ` Junio C Hamano
2020-10-12 19:52     ` Junio C Hamano [this message]
2020-10-13  6:35       ` Michał Kępień
2020-10-12  9:17   ` [PATCH v2 2/3] diff: add -I<regex> that ignores matching changes Michał Kępień
2020-10-12 11:20     ` Johannes Schindelin
2020-10-12 20:00       ` Junio C Hamano
2020-10-12 20:39         ` Johannes Schindelin
2020-10-12 21:43           ` Junio C Hamano
2020-10-13  6:37             ` Michał Kępień
2020-10-13 15:49               ` Junio C Hamano
2020-10-13  6:36       ` Michał Kępień
2020-10-13 12:02         ` Johannes Schindelin
2020-10-13 15:53           ` Junio C Hamano
2020-10-13 18:45           ` Michał Kępień
2020-10-12 18:01     ` Junio C Hamano
2020-10-13  6:38       ` Michał Kępień
2020-10-12 20:04     ` Junio C Hamano
2020-10-13  6:38       ` Michał Kępień
2020-10-12  9:17   ` [PATCH v2 3/3] t: add -I<regex> tests Michał Kępień
2020-10-12 11:49     ` Johannes Schindelin
2020-10-13  6:38       ` Michał Kępień
2020-10-13 12:00         ` Johannes Schindelin
2020-10-13 16:00           ` Junio C Hamano
2020-10-13 19:01           ` Michał Kępień
2020-10-15 11:45             ` Johannes Schindelin
2020-10-15  7:24   ` [PATCH v3 0/2] diff: add -I<regex> that ignores matching changes Michał Kępień
2020-10-15  7:24     ` [PATCH v3 1/2] merge-base, xdiff: zero out xpparam_t structures Michał Kępień
2020-10-15  7:24     ` [PATCH v3 2/2] diff: add -I<regex> that ignores matching changes Michał Kępień
2020-10-16 15:32       ` Phillip Wood
2020-10-16 18:04         ` Junio C Hamano
2020-10-19  9:48           ` Michał Kępień
2020-10-16 18:16       ` Junio C Hamano
2020-10-19  9:55         ` Michał Kępień
2020-10-19 17:29           ` Junio C Hamano
2020-10-16 10:00     ` [PATCH v3 0/2] " Johannes Schindelin
2020-10-20  6:48     ` [PATCH v4 " Michał Kępień
2020-10-20  6:48       ` [PATCH v4 1/2] merge-base, xdiff: zero out xpparam_t structures Michał Kępień
2020-10-20  6:48       ` [PATCH v4 2/2] diff: add -I<regex> that ignores matching changes Michał Kępień
2021-02-05 14:13       ` [PATCH 1/2] diff: add an API for deferred freeing Ævar Arnfjörð Bjarmason
2021-02-10 16:00         ` Johannes Schindelin
2021-02-11  3:00           ` Ævar Arnfjörð Bjarmason
2021-02-11  9:40             ` Johannes Schindelin
2021-02-11 10:21               ` Jeff King
2021-02-11 10:45                 ` [PATCH v2 0/2] " Ævar Arnfjörð Bjarmason
2021-02-11 10:45                 ` [PATCH v2 1/2] " Ævar Arnfjörð Bjarmason
2021-02-11 10:45                 ` [PATCH v2 2/2] diff: plug memory leak from regcomp() on {log,diff} -I Ævar Arnfjörð Bjarmason
2021-02-05 14:13       ` [PATCH " Ævar Arnfjörð Bjarmason

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