The function xdl_refine_conflicts() tries to break down huge conflicts by doing a diff on the conflicting regions. However, this does not make sense when one side is empty. Worse, when one side is not only empty, but after EOF, the code accessed unmapped memory. Noticed by Luben Tuikov, Shawn Pearce and Alexandre Julliard, the latter providing a test case. Signed-off-by: Johannes Schindelin <Johannes.Schindelin@xxxxxx> --- Thank you Alexandre! I looked for the bug for quite some time, but was never close to the real culprit. t/t6023-merge-file.sh | 22 ++++++++++++++++++++++ xdiff/xmerge.c | 4 ++++ 2 files changed, 26 insertions(+), 0 deletions(-) diff --git a/t/t6023-merge-file.sh b/t/t6023-merge-file.sh index 5d9b6f3..1c21d8c 100644 --- a/t/t6023-merge-file.sh +++ b/t/t6023-merge-file.sh @@ -112,5 +112,27 @@ EOF test_expect_success "expected conflict markers, with -L" \ "diff -u test.txt expect.txt" +sed "s/ tu / TU /" < new1.txt > new5.txt +test_expect_failure "conflict in removed tail" \ + "git-merge-file -p orig.txt new1.txt new5.txt > out" + +cat > expect << EOF +Dominus regit me, +et nihil mihi deerit. +In loco pascuae ibi me collocavit, +super aquam refectionis educavit me; +animam meam convertit, +deduxit me super semitas jusitiae, +propter nomen suum. +<<<<<<< orig.txt +======= +Nam et si ambulavero in medio umbrae mortis, +non timebo mala, quoniam TU mecum es: +virga tua et baculus tuus ipsa me consolata sunt. +>>>>>>> new5.txt +EOF + +test_expect_success "expected conflict markers" "diff -u expect out" + test_done diff --git a/xdiff/xmerge.c b/xdiff/xmerge.c index 352207e..294450b 100644 --- a/xdiff/xmerge.c +++ b/xdiff/xmerge.c @@ -190,6 +190,10 @@ static int xdl_refine_conflicts(xdfenv_t *xe1, xdfenv_t *xe2, xdmerge_t *m, if (m->mode) continue; + /* no sense refining a conflict when one side is empty */ + if (m->chg1 == 0 || m->chg2 == 0) + continue; + /* * This probably does not work outside git, since * we have a very simple mmfile structure. -- 1.5.0.rc0.g09372-dirty - To unsubscribe from this list: send the line "unsubscribe git" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html