From: Thomas Rast Date: Tue, 09 Jul 2013 09:31:49 GMT Subject: Re: [PATCH v2 2/2] range_set: fix coalescing bug when range is a subset of another Message-ID: <8738rogjui.fsf@linux-k42r.v.cablecom.net> In-Reply-To: <1373349305-63917-3-git-send-email-sunshine@sunshineco.com> Eric Sunshine writes: > When coalescing ranges, sort_and_merge_range_set() unconditionally > assumes that the end of a range being folded into a preceding range > should become the end of the coalesced range. This assumption, however, > is invalid when one range is a subset of another. For example, given > ranges 1-5 and 2-3 added via range_set_append_unsafe(), > sort_and_merge_range_set() incorrectly coalesces them to range 1-3 > rather than the correct union range 1-5. Fix this bug. > > Signed-off-by: Eric Sunshine > --- > line-log.c | 3 ++- > t/t4211-line-log.sh | 4 ++-- > 2 files changed, 4 insertions(+), 3 deletions(-) > > diff --git a/line-log.c b/line-log.c > index 4bbb09b..8cc29a0 100644 > --- a/line-log.c > +++ b/line-log.c > @@ -116,7 +116,8 @@ static void sort_and_merge_range_set(struct range_set *rs) > > for (i = 1; i < rs->nr; i++) { > if (rs->ranges[i].start <= rs->ranges[o-1].end) { > - rs->ranges[o-1].end = rs->ranges[i].end; > + if (rs->ranges[o-1].end < rs->ranges[i].end) > + rs->ranges[o-1].end = rs->ranges[i].end; Ouch. Thanks for finding and fixing this. Acked-by: Thomas Rast -- Thomas Rast trast@{inf,student}.ethz.ch