From fa5ba2c1dd0ce1bd060f423e7b1eb39d06fcd2cd Mon Sep 17 00:00:00 2001 From: Jeff King Date: Thu, 12 Oct 2017 20:18:37 -0400 Subject: [PATCH] diff: fix infinite loop with --color-moved --ignore-space-change The --color-moved code uses next_byte() to advance through the blob contents. When the user has asked to ignore whitespace changes, we try to collapse any whitespace change down to a single space. However, we enter the conditional block whenever we see the IGNORE_WHITESPACE_CHANGE flag, even if the next byte isn't whitespace. This means that the combination of "--color-moved and --ignore-space-change" was completely broken. Worse, because we return from next_byte() without having advanced our pointer, the function makes no forward progress in the buffer and loops infinitely. Fix this by entering the conditional only when we actually see whitespace. We can apply this also to the IGNORE_WHITESPACE change. That code path isn't buggy (because it falls through to returning the next non-whitespace byte), but it makes the logic more clear if we only bother to look at whitespace flags after seeing that the next byte is whitespace. Reported-by: Orgad Shaneh Signed-off-by: Jeff King Signed-off-by: Junio C Hamano --- diff.c | 28 +++++++++++++++------------- t/t4015-diff-whitespace.sh | 9 +++++++++ 2 files changed, 24 insertions(+), 13 deletions(-) diff --git a/diff.c b/diff.c index 0c604726c0..af9b952886 100644 --- a/diff.c +++ b/diff.c @@ -720,20 +720,22 @@ static int next_byte(const char **cp, const char **endp, if (*cp > *endp) return -1; - if (DIFF_XDL_TST(diffopt, IGNORE_WHITESPACE_CHANGE)) { - while (*cp < *endp && isspace(**cp)) - (*cp)++; - /* - * After skipping a couple of whitespaces, we still have to - * account for one space. - */ - return (int)' '; - } + if (isspace(**cp)) { + if (DIFF_XDL_TST(diffopt, IGNORE_WHITESPACE_CHANGE)) { + while (*cp < *endp && isspace(**cp)) + (*cp)++; + /* + * After skipping a couple of whitespaces, + * we still have to account for one space. + */ + return (int)' '; + } - if (DIFF_XDL_TST(diffopt, IGNORE_WHITESPACE)) { - while (*cp < *endp && isspace(**cp)) - (*cp)++; - /* return the first non-ws character via the usual below */ + if (DIFF_XDL_TST(diffopt, IGNORE_WHITESPACE)) { + while (*cp < *endp && isspace(**cp)) + (*cp)++; + /* return the first non-ws character via the usual below */ + } } retval = (unsigned char)(**cp); diff --git a/t/t4015-diff-whitespace.sh b/t/t4015-diff-whitespace.sh index c3b697411a..66cad4d629 100755 --- a/t/t4015-diff-whitespace.sh +++ b/t/t4015-diff-whitespace.sh @@ -1406,4 +1406,13 @@ test_expect_success 'move detection with submodules' ' test_cmp expect decoded_actual ' +test_expect_success 'move detection with whitespace changes' ' + test_when_finished "git reset --hard" && + test_seq 10 >test && + git add test && + sed s/3/42/ test.tmp && + mv test.tmp test && + git -c diff.colormoved diff --ignore-space-change -- test +' + test_done -- GitLab