A negative delta depth makes no sense, and the code is not prepared to
handle it. If passed "--depth=-1" on the command line, then this line
from break_delta_chains():
cur->depth = (total_depth--) % (depth + 1);
triggers a divide-by-zero. This is undefined behavior according to the C
standard, but on POSIX systems results in SIGFPE killing the process.
This is certainly one way to inform the use that the command was
invalid, but it's a bit friendlier to just treat it as "don't allow any
deltas", which we already do for --depth=0.
Signed-off-by: Jeff King <peff@xxxxxxxx>
---
builtin/pack-objects.c | 2 ++
t/t5316-pack-delta-depth.sh | 7 +++++++
2 files changed, 9 insertions(+)
diff --git a/builtin/pack-objects.c b/builtin/pack-objects.c
index ea7a5b3ba5..da5e0700f9 100644
--- a/builtin/pack-objects.c
+++ b/builtin/pack-objects.c
@@ -3861,6 +3861,8 @@ int cmd_pack_objects(int argc, const char **argv, const char *prefix)
if (pack_to_stdout != !base_name || argc)
usage_with_options(pack_usage, pack_objects_options);
+ if (depth < 0)
+ depth = 0;
if (depth >= (1 << OE_DEPTH_BITS)) {
warning(_("delta chain depth %d is too deep, forcing %d"),
depth, (1 << OE_DEPTH_BITS) - 1);
diff --git a/t/t5316-pack-delta-depth.sh b/t/t5316-pack-delta-depth.sh
index 3e84df4137..759169d074 100755
--- a/t/t5316-pack-delta-depth.sh
+++ b/t/t5316-pack-delta-depth.sh
@@ -102,4 +102,11 @@ test_expect_success '--depth=0 disables deltas' '
test_cmp expect actual
'
+test_expect_success 'negative depth disables deltas' '
+ pack=$(git pack-objects --all --depth=-1 </dev/null pack) &&
+ echo 0 >expect &&
+ max_chain pack-$pack.pack >actual &&
+ test_cmp expect actual
+'
+
test_done
--
2.31.1.875.g5dccece0aa
