Re: [PATCH] xdiff/xprepare: initialise xdlclassifier_t cf in xdl_prepare_env()

From: Junio C Hamano <gitster@pobox.com>
Date: Aug 31, 2011, 17:02 UTC
Message-ID: <7vei01zf89.fsf@alter.siamese.dyndns.org>
In-Reply-To: <1314766126-5060-1-git-send-email-rctay89@gmail.com>

Tay Ray Chuan <rctay89@gmail.com> writes:

Show 6 quoted lines

> Ensure that the xdl_free_classifier() call on xdlclassifier_t cf is safe
> even if xdl_init_classifier() isn't called. This may occur in the case
> where diff is run with --histogram and a call to, say, xdl_prepare_ctx()
> fails.
>
> Signed-off-by: Tay Ray Chuan <rctay89@gmail.com>

Thanks. Did you find this by code inspection?

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>  xdiff/xprepare.c |    3 +++
>  1 files changed, 3 insertions(+), 0 deletions(-)
>
> diff --git a/xdiff/xprepare.c b/xdiff/xprepare.c
> index 620fc9a..4323596 100644
> --- a/xdiff/xprepare.c
> +++ b/xdiff/xprepare.c
> @@ -239,6 +239,9 @@ int xdl_prepare_env(mmfile_t *mf1, mmfile_t *mf2, xpparam_t const *xpp,
>  	long enl1, enl2, sample;
>  	xdlclassifier_t cf;
>  
> +	cf.rchash = NULL;
> +	cf.ncha.head = NULL;

Would it be more appropriate to use memcpy(&cf, 0, sizeof(cf)) instead, so that we wouldn't have to worry about a similar breakage when a new field is added to "struct xdlclassifier" later?