From cfd0163d641e785f20d29b70edf83c777941594f Mon Sep 17 00:00:00 2001 From: Johannes Schindelin Date: Tue, 30 Aug 2022 13:54:22 +0000 Subject: add -p: avoid ambiguous signed/unsigned comparison In the interactive `add` operation, users can choose to jump to specific hunks, and Git will present the hunk list in that case. To avoid showing too many lines at once, only a maximum of 21 hunks are shown, skipping the "mode change" pseudo hunk. The comparison performed to skip the "mode change" pseudo hunk (if any) compares a signed integer `i` to the unsigned value `mode_change` (which can be 0 or 1 because it is a 1-bit type). According to section 6.3.1.8 of the C99 standard (see e.g. https://www.open-std.org/jtc1/sc22/WG14/www/docs/n1256.pdf), what should happen is an automatic conversion of the "lesser" type to the "greater" type, but since the types differ in signedness, it is ill-defined what is the correct "usual arithmetic conversion". Which means that Visual C's behavior can (and does) differ from GCC's: When compiling Git using the latter, `add -p`'s `goto` command shows no hunks by default because it casts a negative start offset to a pretty large unsigned value, breaking the "goto hunk" test case in `t3701-add-interactive.sh`. Let's avoid that by converting the unsigned bit explicitly to a signed integer. Note: This is a long-standing bug in the Visual C build of Git, but it has never been caught because t3701 is skipped when `NO_PERL` is set, which is the case in the `vs-test` jobs of Git's CI runs. Signed-off-by: Johannes Schindelin Signed-off-by: Junio C Hamano --- add-patch.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'add-patch.c') diff --git a/add-patch.c b/add-patch.c index 509ca04456..3524555e2b 100644 --- a/add-patch.c +++ b/add-patch.c @@ -1547,7 +1547,7 @@ soft_increment: strbuf_remove(&s->answer, 0, 1); strbuf_trim(&s->answer); i = hunk_index - DISPLAY_HUNKS_LINES / 2; - if (i < file_diff->mode_change) + if (i < (int)file_diff->mode_change) i = file_diff->mode_change; while (s->answer.len == 0) { i = display_hunks(s, file_diff, i); -- cgit v1.2.1