bundle: output hash information in 'verify'

The previous change moved the 'filter' capability to the end of the 'git
bundle verify' output. Now, add the 'object-format' capability to the
output, when it exists.

This change makes 'git bundle verify' output the hash used in all cases,
even if the capability is not in the bundle. This means that v2 bundles
will always output that they use "sha1". This might look noisy to some
users, but it does simplify the implementation and the test strategy for
this feature.

Since 'verify' ends early when a prerequisite commit is missing, we need
to insert this hash message carefully into our expected test output
throughout t6020.

Signed-off-by: Derrick Stolee <derrickstolee@github.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

bundle.c

@@ -278,6 +278,8 @@ int verify_bundle(struct repository *r,
 			list_refs(r, 0, NULL);
 		}
 
+		printf_ln("The bundle uses this hash algorithm: %s",
+			  header->hash_algo->name);
 		if (header->filter.choice)
 			printf_ln("The bundle uses this filter: %s",
 				  list_objects_filter_spec(&header->filter));

t/t6020-bundle-misc.sh

@@ -122,6 +122,8 @@ format_and_save_expect () {
 	sed -e 's/Z$//' >expect
 }
 
+HASH_MESSAGE="The bundle uses this hash algorithm: $GIT_DEFAULT_HASH"
+
 #            (C)   (D, pull/1/head, topic/1)
 #             o --- o
 #            /       \                              (L)
@@ -194,11 +196,12 @@ test_expect_success 'create bundle from special rev: main^!' '
 
 	git bundle verify special-rev.bdl |
 		make_user_friendly_and_stable_output >actual &&
-	format_and_save_expect <<-\EOF &&
+	format_and_save_expect <<-EOF &&
 	The bundle contains this ref:
 	<COMMIT-P> refs/heads/main
 	The bundle requires this ref:
 	<COMMIT-O> Z
+	$HASH_MESSAGE
 	EOF
 	test_cmp expect actual &&
 
@@ -215,12 +218,13 @@ test_expect_success 'create bundle with --max-count option' '
 
 	git bundle verify max-count.bdl |
 		make_user_friendly_and_stable_output >actual &&
-	format_and_save_expect <<-\EOF &&
+	format_and_save_expect <<-EOF &&
 	The bundle contains these 2 refs:
 	<COMMIT-P> refs/heads/main
 	<TAG-1> refs/tags/v1
 	The bundle requires this ref:
 	<COMMIT-O> Z
+	$HASH_MESSAGE
 	EOF
 	test_cmp expect actual &&
 
@@ -240,7 +244,7 @@ test_expect_success 'create bundle with --since option' '
 
 	git bundle verify since.bdl |
 		make_user_friendly_and_stable_output >actual &&
-	format_and_save_expect <<-\EOF &&
+	format_and_save_expect <<-EOF &&
 	The bundle contains these 5 refs:
 	<COMMIT-P> refs/heads/main
 	<COMMIT-N> refs/heads/release
@@ -250,6 +254,7 @@ test_expect_success 'create bundle with --since option' '
 	The bundle requires these 2 refs:
 	<COMMIT-M> Z
 	<COMMIT-K> Z
+	$HASH_MESSAGE
 	EOF
 	test_cmp expect actual &&
 
@@ -267,11 +272,12 @@ test_expect_success 'create bundle 1 - no prerequisites' '
 	EOF
 	git bundle create stdin-1.bdl --stdin <input &&
 
-	cat >expect <<-\EOF &&
+	format_and_save_expect <<-EOF &&
 	The bundle contains these 2 refs:
 	<COMMIT-D> refs/heads/topic/1
 	<COMMIT-H> refs/heads/topic/2
 	The bundle records a complete history.
+	$HASH_MESSAGE
 	EOF
 
 	# verify bundle, which has no prerequisites
@@ -308,13 +314,14 @@ test_expect_success 'create bundle 2 - has prerequisites' '
 		--stdin \
 		release <input &&
 
-	format_and_save_expect <<-\EOF &&
+	format_and_save_expect <<-EOF &&
 	The bundle contains this ref:
 	<COMMIT-N> refs/heads/release
 	The bundle requires these 3 refs:
 	<COMMIT-D> Z
 	<COMMIT-E> Z
 	<COMMIT-G> Z
+	$HASH_MESSAGE
 	EOF
 
 	git bundle verify 2.bdl |
@@ -367,13 +374,14 @@ test_expect_success 'create bundle 3 - two refs, same object' '
 		--stdin \
 		main HEAD <input &&
 
-	format_and_save_expect <<-\EOF &&
+	format_and_save_expect <<-EOF &&
 	The bundle contains these 2 refs:
 	<COMMIT-P> refs/heads/main
 	<COMMIT-P> HEAD
 	The bundle requires these 2 refs:
 	<COMMIT-M> Z
 	<COMMIT-K> Z
+	$HASH_MESSAGE
 	EOF
 
 	git bundle verify 3.bdl |
@@ -409,12 +417,13 @@ test_expect_success 'create bundle 4 - with tags' '
 		--stdin \
 		--all <input &&
 
-	cat >expect <<-\EOF &&
+	cat >expect <<-EOF &&
 	The bundle contains these 3 refs:
 	<TAG-1> refs/tags/v1
 	<TAG-2> refs/tags/v2
 	<TAG-3> refs/tags/v3
 	The bundle records a complete history.
+	$HASH_MESSAGE
 	EOF
 
 	git bundle verify 4.bdl |
@@ -511,6 +520,7 @@ do
 		<TAG-3> refs/tags/v3
 		<COMMIT-P> HEAD
 		The bundle records a complete history.
+		$HASH_MESSAGE
 		The bundle uses this filter: $filter
 		EOF
 		test_cmp expect actual &&