[PATCH 08/13] object-file: handle compatibility algorithm

[Christian Couder <christian.couder@gmail.com>]

From: "brian m. carlson" <sandals@crustytoothpaste.net>

When we check in a large blob, we stream it directly to a pack and then
write an index.  However, in compatibility mode, we also need to make
sure to compute the object ID for the compatibility algorithm as well as
the main algorithm or we will incorrectly store the null OID in the
index we create.  Do so here to avoid corrupting the repository.

Add a test that adds a large file in a repository with a compatibility
algorithm.

Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Christian Couder <christian.couder@gmail.com>
---
 object-file.c                 | 18 ++++++++++++++++--
 t/t1016-compatObjectFormat.sh | 14 ++++++++++++++
 2 files changed, 30 insertions(+), 2 deletions(-)

diff --git a/object-file.c b/object-file.c
index c049bf13f7..b4c4a2ea0f 100644
--- a/object-file.c
+++ b/object-file.c
@@ -747,6 +747,7 @@ static int hash_stream(struct odb_stream *stream,
  */
 static void stream_to_pack(struct transaction_packfile *state,
 			   struct git_hash_ctx *ctx,
+			   struct git_hash_ctx *compat_ctx,
 			   struct odb_stream *stream)
 {
 	git_zstream s;
@@ -774,6 +775,9 @@ static void stream_to_pack(struct transaction_packfile *state,
 				is_finished = true;
 
 			git_hash_update(ctx, ibuf, rsize);
+			if (compat_ctx)
+				git_hash_update(compat_ctx,
+						ibuf, rsize);
 
 			s.next_in = ibuf;
 			s.avail_in = rsize;
@@ -882,16 +886,22 @@ static int odb_transaction_files_write_object_stream(struct odb_transaction *bas
 								 struct odb_transaction_files,
 								 base);
 	struct transaction_packfile *state = &transaction->packfile;
-	struct git_hash_ctx ctx;
+	struct git_hash_ctx ctx, compat_ctx;
+	struct object_id compat_oid;
 	unsigned char obuf[16384];
 	unsigned header_len;
 	struct hashfile_checkpoint checkpoint;
 	struct pack_idx_entry *idx;
+	const struct git_hash_algo *compat = transaction->base.source->odb->repo->compat_hash_algo;
 
 	header_len = format_object_header((char *)obuf, sizeof(obuf),
 					  stream->type, stream->size);
 	git_hash_init(&ctx, transaction->base.source->odb->repo->hash_algo);
 	git_hash_update(&ctx, obuf, header_len);
+	if (compat) {
+		git_hash_init(&compat_ctx, compat);
+		git_hash_update(&compat_ctx, obuf, header_len);
+	}
 
 	/*
 	 * If writing another object to the packfile could result in it
@@ -916,8 +926,10 @@ static int odb_transaction_files_write_object_stream(struct odb_transaction *bas
 	hashfile_checkpoint(state->f, &checkpoint);
 	idx->offset = state->offset;
 	crc32_begin(state->f);
-	stream_to_pack(state, &ctx, stream);
+	stream_to_pack(state, &ctx, compat ? &compat_ctx : NULL, stream);
 	git_hash_final_oid(result_oid, &ctx);
+	if (compat)
+		git_hash_final_oid(&compat_oid, &compat_ctx);
 
 	idx->crc32 = crc32_end(state->f);
 	if (already_written(transaction, result_oid)) {
@@ -926,6 +938,8 @@ static int odb_transaction_files_write_object_stream(struct odb_transaction *bas
 		free(idx);
 	} else {
 		oidcpy(&idx->oid, result_oid);
+		if (compat)
+			oidcpy(&idx->compat_oid, &compat_oid);
 		ALLOC_GROW(state->written,
 			   state->nr_written + 1,
 			   state->alloc_written);
diff --git a/t/t1016-compatObjectFormat.sh b/t/t1016-compatObjectFormat.sh
index 1560b6a2e2..af9532aa1f 100755
--- a/t/t1016-compatObjectFormat.sh
+++ b/t/t1016-compatObjectFormat.sh
@@ -228,6 +228,20 @@ do
 		test_copy_bytes 8 <v3.idx | test-tool hexdump >actual &&
 		test_cmp expect actual
 	'
+
+	test_expect_success 'add a large file streamed into a pack' '
+		test_when_finished "rm -rf large-repo" &&
+		create_compat_repo $hash large-repo &&
+		git -C large-repo config set core.bigFileThreshold 1k &&
+		test-tool genrandom large 5000 >large-repo/large &&
+		git -C large-repo add large &&
+		ls large-repo/.git/objects/pack/pack-*.pack &&
+		git -C large-repo hash-object large >expect &&
+		git -C large-repo rev-parse :large >actual &&
+		test_cmp expect actual &&
+		git -C large-repo cat-file blob :large >actual &&
+		test_cmp large-repo/large actual
+	'
 done
 cd "$base"
 
-- 
2.56.0.215.g47fdf2208c