1 files changed, 83 insertions, 0 deletions
diff --git a/third_party/git/t/t5309-pack-delta-cycles.sh b/third_party/git/t/t5309-pack-delta-cycles.sh
new file mode 100755
index 000000000000..491556dad979
--- /dev/null
+++ b/third_party/git/t/t5309-pack-delta-cycles.sh
@@ -0,0 +1,83 @@
+#!/bin/sh
+
+test_description='test index-pack handling of delta cycles in packfiles'
+. ./test-lib.sh
+. "$TEST_DIRECTORY"/lib-pack.sh
+
+if ! test_have_prereq SHA1
+then
+       skip_all='not using SHA-1 for objects'
+       test_done
+fi
+
+# Two similar-ish objects that we have computed deltas between.
+A=01d7713666f4de822776c7622c10f1b07de280dc
+B=e68fe8129b546b101aee9510c5328e7f21ca1d18
+
+# double-check our hand-constucted packs
+test_expect_success 'index-pack works with a single delta (A->B)' '
+	clear_packs &&
+	{
+		pack_header 2 &&
+		pack_obj $A $B &&
+		pack_obj $B
+	} >ab.pack &&
+	pack_trailer ab.pack &&
+	git index-pack --stdin <ab.pack &&
+	git cat-file -t $A &&
+	git cat-file -t $B
+'
+
+test_expect_success 'index-pack works with a single delta (B->A)' '
+	clear_packs &&
+	{
+		pack_header 2 &&
+		pack_obj $A &&
+		pack_obj $B $A
+	} >ba.pack &&
+	pack_trailer ba.pack &&
+	git index-pack --stdin <ba.pack &&
+	git cat-file -t $A &&
+	git cat-file -t $B
+'
+
+test_expect_success 'index-pack detects missing base objects' '
+	clear_packs &&
+	{
+		pack_header 1 &&
+		pack_obj $A $B
+	} >missing.pack &&
+	pack_trailer missing.pack &&
+	test_must_fail git index-pack --fix-thin --stdin <missing.pack
+'
+
+test_expect_success 'index-pack detects REF_DELTA cycles' '
+	clear_packs &&
+	{
+		pack_header 2 &&
+		pack_obj $A $B &&
+		pack_obj $B $A
+	} >cycle.pack &&
+	pack_trailer cycle.pack &&
+	test_must_fail git index-pack --fix-thin --stdin <cycle.pack
+'
+
+test_expect_failure 'failover to an object in another pack' '
+	clear_packs &&
+	git index-pack --stdin <ab.pack &&
+	git index-pack --stdin --fix-thin <cycle.pack
+'
+
+test_expect_failure 'failover to a duplicate object in the same pack' '
+	clear_packs &&
+	{
+		pack_header 3 &&
+		pack_obj $A $B &&
+		pack_obj $B $A &&
+		pack_obj $A
+	} >recoverable.pack &&
+	pack_trailer recoverable.pack &&
+	git index-pack --fix-thin --stdin <recoverable.pack
+'
+
+test_done