"git apply" can work outside a repository as a better "GNU patch",
but when it does so, it still assumed that it can access
the_hash_algo, which is no longer true in the new world order.

Make sure we explicitly fall back to SHA-1 algorithm for backward
compatibility.

Signed-off-by: Junio C Hamano <redacted>
---
 builtin/apply.c         | 4 ++++
 t/t1517-outside-repo.sh | 2 +-
 2 files changed, 5 insertions(+), 1 deletion(-)

diff --git a/builtin/apply.c b/builtin/apply.c
index 861a01910c..e9175f820f 100644
--- a/builtin/apply.c
+++ b/builtin/apply.c

@@ -1,6 +1,7 @@
 #include "builtin.h"
 #include "gettext.h"
 #include "repository.h"
+#include "hash.h"
 #include "apply.h"
 
 static const char * const apply_usage[] = {

@@ -18,6 +19,9 @@ int cmd_apply(int argc, const char **argv, const char *prefix)
 	if (init_apply_state(&state, the_repository, prefix))
 		exit(128);
 
+	if (!the_hash_algo)
+		repo_set_hash_algo(the_repository, GIT_HASH_SHA1);
+

 	argc = apply_parse_options(argc, argv,
 				   &state, &force_apply, &options,
 				   apply_usage);

diff --git a/t/t1517-outside-repo.sh b/t/t1517-outside-repo.sh
index 2d8982d61a..557808ffa7 100755
--- a/t/t1517-outside-repo.sh
+++ b/t/t1517-outside-repo.sh

@@ -37,7 +37,7 @@ test_expect_success 'hash-object outside repository (uses SHA-1)' '
 	test_cmp hash.expect hash.actual
 '
 
-test_expect_failure 'apply a patch outside repository' '
+test_expect_success 'apply a patch outside repository' '
 	(
 		cd non-repo &&
 		cp ../nums.old nums &&

-- 
2.45.1-216-g4365c6fcf9