5 files changed, 23 insertions, 4 deletions
diff --git a/src/libgit2/odb.c b/src/libgit2/odb.c
index edf4f001f..d50c7df9b 100644
--- a/src/libgit2/odb.c
+++ b/src/libgit2/odb.c
@@ -587,6 +587,13 @@ static int add_backend_internal(
 
 	GIT_ERROR_CHECK_VERSION(backend, GIT_ODB_BACKEND_VERSION, "git_odb_backend");
 
+#ifdef GIT_EXPERIMENTAL_SHA256
+	if (!backend->oid_type) {
+		git_error_set(GIT_ERROR_ODB, "backend oid type is not set");
+		return -1;
+	}
+#endif
+
 	/* Check if the backend is already owned by another ODB */
 	GIT_ASSERT(!backend->odb || backend->odb == odb);
 
@@ -1704,7 +1711,6 @@ int git_odb_open_wstream(
 	    (error = hash_header(ctx, size, type)) < 0)
 		goto done;
 
-	(*stream)->oid_type = db->options.oid_type;
 	(*stream)->hash_ctx = ctx;
 	(*stream)->declared_size = size;
 	(*stream)->received_bytes = 0;
@@ -1750,7 +1756,7 @@ int git_odb_stream_finalize_write(git_oid *out, git_odb_stream *stream)
 	git_hash_final(out->id, stream->hash_ctx);
 
 #ifdef GIT_EXPERIMENTAL_SHA256
-	out->type = stream->oid_type;
+	out->type = stream->backend->oid_type;
 #endif
 
 	if (git_odb__freshen(stream->backend->odb, out))
diff --git a/src/libgit2/odb.h b/src/libgit2/odb.h
index 7a712e202..6bdacd384 100644
--- a/src/libgit2/odb.h
+++ b/src/libgit2/odb.h
@@ -180,7 +180,7 @@ int git_odb__hashfile(
 	git_object_t object_type,
 	git_oid_t oid_type);
 
-GIT_EXTERN(int) git_odb__backend_loose(
+int git_odb__backend_loose(
 	git_odb_backend **out,
 	const char *objects_dir,
 	git_odb_backend_loose_options *opts);
diff --git a/src/libgit2/odb_loose.c b/src/libgit2/odb_loose.c
index d1abbe233..306cbf9ad 100644
--- a/src/libgit2/odb_loose.c
+++ b/src/libgit2/odb_loose.c
@@ -1179,14 +1179,20 @@ int git_odb__backend_loose(
 	backend = git__calloc(1, alloclen);
 	GIT_ERROR_CHECK_ALLOC(backend);
 
+	normalize_options(&backend->options, opts);
+
 	backend->parent.version = GIT_ODB_BACKEND_VERSION;
+
+#ifdef GIT_EXPERIMENTAL_SHA256
+	backend->parent.oid_type = backend->options.oid_type;
+#endif
+
 	backend->objects_dirlen = objects_dirlen;
 	memcpy(backend->objects_dir, objects_dir, objects_dirlen);
 
 	if (backend->objects_dir[backend->objects_dirlen - 1] != '/')
 		backend->objects_dir[backend->objects_dirlen++] = '/';
 
-	normalize_options(&backend->options, opts);
 	backend->oid_hexsize = git_oid_hexsize(backend->options.oid_type);
 
 	backend->parent.read = &loose_backend__read;
diff --git a/src/libgit2/odb_mempack.c b/src/libgit2/odb_mempack.c
index 6f27f45f8..8c83fcee6 100644
--- a/src/libgit2/odb_mempack.c
+++ b/src/libgit2/odb_mempack.c
@@ -178,6 +178,9 @@ int git_mempack_new(git_odb_backend **out)
 		return -1;
 
 	db->parent.version = GIT_ODB_BACKEND_VERSION;
+#ifdef GIT_EXPERIMENTAL_SHA256
+	db->parent.oid_type = GIT_OID_SHA1;
+#endif
 	db->parent.read = &impl__read;
 	db->parent.write = &impl__write;
 	db->parent.read_header = &impl__read_header;
diff --git a/src/libgit2/odb_pack.c b/src/libgit2/odb_pack.c
index 1b1d122b0..b0a6ae097 100644
--- a/src/libgit2/odb_pack.c
+++ b/src/libgit2/odb_pack.c
@@ -883,6 +883,10 @@ static int pack_backend__alloc(
 
 	backend->parent.version = GIT_ODB_BACKEND_VERSION;
 
+#ifdef GIT_EXPERIMENTAL_SHA256
+	backend->parent.oid_type = backend->opts.oid_type;
+#endif
+
 	backend->parent.read = &pack_backend__read;
 	backend->parent.read_prefix = &pack_backend__read_prefix;
 	backend->parent.read_header = &pack_backend__read_header;