thodg/libgit2

diff --git a/src/odb.c b/src/odb.c
index 21b46bf..9785c74 100644
--- a/src/odb.c
+++ b/src/odb.c
@@ -622,7 +622,7 @@ attempt_lookup:
 		backend_internal *internal = git_vector_get(&db->backends, i);
 		git_odb_backend *b = internal->backend;
 
-		if (b->exists != NULL)
+		if (b->exists != NULL && (!refreshed || b->refresh))
 			found = b->exists(b, id);
 	}
 
@@ -717,7 +717,7 @@ attempt_lookup:
 		backend_internal *internal = git_vector_get(&db->backends, i);
 		git_odb_backend *b = internal->backend;
 
-		if (b->read != NULL) {
+		if (b->read != NULL && (!refreshed || b->refresh)) {
 			++reads;
 			error = b->read(&raw.data, &raw.len, &raw.type, b, id);
 		}
@@ -774,7 +774,7 @@ attempt_lookup:
 		backend_internal *internal = git_vector_get(&db->backends, i);
 		git_odb_backend *b = internal->backend;
 
-		if (b->read_prefix != NULL) {
+		if (b->read_prefix != NULL && (!refreshed || b->refresh)) {
 			git_oid full_oid;
 			error = b->read_prefix(&full_oid, &raw.data, &raw.len, &raw.type, b, short_id, len);
 			if (error == GIT_ENOTFOUND || error == GIT_PASSTHROUGH)
diff --git a/tests-clar/odb/backend/nonrefreshing.c b/tests-clar/odb/backend/nonrefreshing.c
new file mode 100644
index 0000000..abb824d
--- /dev/null
+++ b/tests-clar/odb/backend/nonrefreshing.c
@@ -0,0 +1,261 @@
+#include "clar_libgit2.h"
+#include "git2/sys/odb_backend.h"
+#include "repository.h"
+
+typedef struct fake_backend {
+	git_odb_backend parent;
+
+	git_error_code error_code;
+
+	int exists_calls;
+	int read_calls;
+	int read_header_calls;
+	int read_prefix_calls;
+} fake_backend;
+
+static git_repository *_repo;
+static fake_backend *_fake;
+static git_oid _oid;
+
+static int fake_backend__exists(git_odb_backend *backend, const git_oid *oid)
+{
+	fake_backend *fake;
+
+	GIT_UNUSED(oid);
+
+	fake = (fake_backend *)backend;
+
+	fake->exists_calls++;
+
+	return (fake->error_code == GIT_OK);
+}
+
+static int fake_backend__read(
+	void **buffer_p, size_t *len_p, git_otype *type_p,
+	git_odb_backend *backend, const git_oid *oid)
+{
+	fake_backend *fake;
+
+	GIT_UNUSED(buffer_p);
+	GIT_UNUSED(len_p);
+	GIT_UNUSED(type_p);
+	GIT_UNUSED(oid);
+
+	fake = (fake_backend *)backend;
+
+	fake->read_calls++;
+
+	*len_p = 0;
+	*buffer_p = NULL;
+	*type_p = GIT_OBJ_BLOB;
+
+	return fake->error_code;
+}
+
+static int fake_backend__read_header(
+	size_t *len_p, git_otype *type_p,
+	git_odb_backend *backend, const git_oid *oid)
+{
+	fake_backend *fake;
+
+	GIT_UNUSED(len_p);
+	GIT_UNUSED(type_p);
+	GIT_UNUSED(oid);
+
+	fake = (fake_backend *)backend;
+
+	fake->read_header_calls++;
+
+	*len_p = 0;
+	*type_p = GIT_OBJ_BLOB;
+
+	return fake->error_code;
+}
+
+static int fake_backend__read_prefix(
+	git_oid *out_oid, void **buffer_p, size_t *len_p, git_otype *type_p,
+	git_odb_backend *backend, const git_oid *short_oid,	size_t len)
+{
+	fake_backend *fake;
+
+	GIT_UNUSED(out_oid);
+	GIT_UNUSED(buffer_p);
+	GIT_UNUSED(len_p);
+	GIT_UNUSED(type_p);
+	GIT_UNUSED(short_oid);
+	GIT_UNUSED(len);
+
+	fake = (fake_backend *)backend;
+
+	fake->read_prefix_calls++;
+
+	*len_p = 0;
+	*buffer_p = NULL;
+	*type_p = GIT_OBJ_BLOB;
+
+	return fake->error_code;
+}
+
+static void fake_backend__free(git_odb_backend *_backend)
+{
+	fake_backend *backend;
+
+	backend = (fake_backend *)_backend;
+
+	git__free(backend);
+}
+
+static int build_fake_backend(
+	git_odb_backend **out,
+	git_error_code error_code)
+{
+	fake_backend *backend;
+
+	backend = git__calloc(1, sizeof(fake_backend));
+	GITERR_CHECK_ALLOC(backend);
+
+	backend->parent.version = GIT_ODB_BACKEND_VERSION;
+
+	backend->parent.refresh = NULL;
+	backend->error_code = error_code;
+
+	backend->parent.read = fake_backend__read;
+	backend->parent.read_prefix = fake_backend__read_prefix;
+	backend->parent.read_header = fake_backend__read_header;
+	backend->parent.exists = fake_backend__exists;
+	backend->parent.free = &fake_backend__free;
+
+	*out = (git_odb_backend *)backend;
+
+	return 0;
+}
+
+static void setup_repository_and_backend(git_error_code error_code)
+{
+	git_odb *odb;
+	git_odb_backend *backend;
+
+	_repo = cl_git_sandbox_init("testrepo.git");
+
+	cl_git_pass(build_fake_backend(&backend, error_code));
+
+	cl_git_pass(git_repository_odb__weakptr(&odb, _repo));
+	cl_git_pass(git_odb_add_backend(odb, backend, 10));
+
+	_fake = (fake_backend *)backend;
+
+	cl_git_pass(git_oid_fromstr(&_oid, "deadbeefdeadbeefdeadbeefdeadbeefdeadbeef"));
+}
+
+void test_odb_backend_nonrefreshing__cleanup(void)
+{
+	cl_git_sandbox_cleanup();
+}
+
+void test_odb_backend_nonrefreshing__exists_is_invoked_once_on_failure(void)
+{
+	git_odb *odb;
+
+	setup_repository_and_backend(GIT_ENOTFOUND);
+
+	cl_git_pass(git_repository_odb__weakptr(&odb, _repo));
+	cl_assert_equal_b(false, git_odb_exists(odb, &_oid));
+
+	cl_assert_equal_i(1, _fake->exists_calls);
+}
+
+void test_odb_backend_nonrefreshing__read_is_invoked_once_on_failure(void)
+{
+	git_object *obj;
+
+	setup_repository_and_backend(GIT_ENOTFOUND);
+
+	cl_git_fail_with(
+		git_object_lookup(&obj, _repo, &_oid, GIT_OBJ_ANY),
+		GIT_ENOTFOUND);
+
+	cl_assert_equal_i(1, _fake->read_calls);
+}
+
+void test_odb_backend_nonrefreshing__readprefix_is_invoked_once_on_failure(void)
+{
+	git_object *obj;
+
+	setup_repository_and_backend(GIT_ENOTFOUND);
+
+	cl_git_fail_with(
+		git_object_lookup_prefix(&obj, _repo, &_oid, 7, GIT_OBJ_ANY),
+		GIT_ENOTFOUND);
+
+	cl_assert_equal_i(1, _fake->read_prefix_calls);
+}
+
+void test_odb_backend_nonrefreshing__readheader_is_invoked_once_on_failure(void)
+{
+	git_odb *odb;
+	size_t len;
+	git_otype type;
+
+	setup_repository_and_backend(GIT_ENOTFOUND);
+
+	cl_git_pass(git_repository_odb__weakptr(&odb, _repo));
+
+	cl_git_fail_with(
+		git_odb_read_header(&len, &type, odb, &_oid),
+		GIT_ENOTFOUND);
+
+	cl_assert_equal_i(1, _fake->read_header_calls);
+}
+
+void test_odb_backend_nonrefreshing__exists_is_invoked_once_on_success(void)
+{
+	git_odb *odb;
+
+	setup_repository_and_backend(GIT_OK);
+
+	cl_git_pass(git_repository_odb__weakptr(&odb, _repo));
+	cl_assert_equal_b(true, git_odb_exists(odb, &_oid));
+
+	cl_assert_equal_i(1, _fake->exists_calls);
+}
+
+void test_odb_backend_nonrefreshing__read_is_invoked_once_on_success(void)
+{
+	git_object *obj;
+
+	setup_repository_and_backend(GIT_OK);
+
+	cl_git_pass(git_object_lookup(&obj, _repo, &_oid, GIT_OBJ_ANY));
+
+	cl_assert_equal_i(1, _fake->read_calls);
+
+	git_object_free(obj);
+}
+
+void test_odb_backend_nonrefreshing__readprefix_is_invoked_once_on_success(void)
+{
+	git_object *obj;
+
+	setup_repository_and_backend(GIT_OK);
+
+	cl_git_pass(git_object_lookup_prefix(&obj, _repo, &_oid, 7, GIT_OBJ_ANY));
+
+	cl_assert_equal_i(1, _fake->read_prefix_calls);
+
+	git_object_free(obj);
+}
+
+void test_odb_backend_nonrefreshing__readheader_is_invoked_once_on_success(void)
+{
+	git_odb *odb;
+	size_t len;
+	git_otype type;
+
+	setup_repository_and_backend(GIT_OK);
+
+	cl_git_pass(git_repository_odb__weakptr(&odb, _repo));
+
+	cl_git_pass(git_odb_read_header(&len, &type, odb, &_oid));
+
+	cl_assert_equal_i(1, _fake->read_header_calls);
+}