update-ref: add support for 'symref-verify' command
The 'symref-verify' command allows users to verify if a provided <ref> contains the provided <old-target> without changing the <ref>. If <old-target> is not provided, the command will verify that the <ref> doesn't exist. The command allows users to verify symbolic refs within a transaction, and this means users can perform a set of changes in a transaction only when the verification holds good. Since we're checking for symbolic refs, this command will only work with the 'no-deref' mode. This is because any dereferenced symbolic ref will point to an object and not a ref and the regular 'verify' command can be used in such situations. Add required tests for symref support in 'verify'. Since we're here, also add reflog checks for the pre-existing 'verify' tests, there is no divergence from behavior, but we never tested to ensure that reflog wasn't affected by the 'verify' command. Helped-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Karthik Nayak <karthik.188@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
Karthik Nayak committed
Jun 7, 2024 at 15:33 UTC
1451ac734ffc1b9c45af12a2485c6d2ee69a6a76
6 files changed
+208
-15
Documentation/git-update-ref.txt
+7
@@ -65,6 +65,7 @@ performs all modifications together. Specify commands of the form:
65
create SP <ref> SP <new-oid> LF
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delete SP <ref> [SP <old-oid>] LF
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verify SP <ref> [SP <old-oid>] LF
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+ symref-verify SP <ref> [SP <old-target>] LF
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option SP <opt> LF
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start LF
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prepare LF
@@ -86,6 +87,7 @@ quoting:
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create SP <ref> NUL <new-oid> NUL
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delete SP <ref> NUL [<old-oid>] NUL
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verify SP <ref> NUL [<old-oid>] NUL
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+ symref-verify SP <ref> [NUL <old-target>] NUL
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option SP <opt> NUL
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start NUL
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prepare NUL
@@ -117,6 +119,11 @@ verify::
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Verify <ref> against <old-oid> but do not change it. If
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<old-oid> is zero or missing, the ref must not exist.
121
122
+symref-verify::
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+ Verify symbolic <ref> against <old-target> but do not change it.
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+ If <old-target> is missing, the ref must not exist. Can only be
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+ used in `no-deref` mode.
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+
127
option::
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Modify the behavior of the next command naming a <ref>.
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The only valid option is `no-deref` to avoid dereferencing
builtin/update-ref.c
+70
-10
@@ -76,6 +76,29 @@ static char *parse_refname(const char **next)
76
return strbuf_detach(&ref, NULL);
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}
78
79
+/*
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+ * Wrapper around parse_refname which skips the next delimiter.
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+ */
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+static char *parse_next_refname(const char **next)
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+{
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+ if (line_termination) {
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+ /* Without -z, consume SP and use next argument */
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+ if (!**next || **next == line_termination)
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+ return NULL;
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+ if (**next != ' ')
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+ die("expected SP but got: %s", *next);
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+ } else {
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+ /* With -z, read the next NUL-terminated line */
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+ if (**next)
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+ return NULL;
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+ }
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+ /* Skip the delimiter */
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+ (*next)++;
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+
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+ return parse_refname(next);
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+}
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+
101
+
102
/*
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* The value being parsed is <old-oid> (as opposed to <new-oid>; the
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* difference affects which error messages are generated):
@@ -297,11 +320,47 @@ static void parse_cmd_verify(struct ref_transaction *transaction,
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die("verify %s: extra input: %s", refname, next);
321
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if (ref_transaction_verify(transaction, refname, &old_oid,
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- update_flags, &err))
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+ NULL, update_flags, &err))
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+ die("%s", err.buf);
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+
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+ update_flags = default_flags;
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+ free(refname);
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+ strbuf_release(&err);
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+}
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+
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+static void parse_cmd_symref_verify(struct ref_transaction *transaction,
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+ const char *next, const char *end)
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+{
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+ struct strbuf err = STRBUF_INIT;
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+ struct object_id old_oid;
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+ char *refname, *old_target;
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+
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+ if (!(update_flags & REF_NO_DEREF))
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+ die("symref-verify: cannot operate with deref mode");
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+
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+ refname = parse_refname(&next);
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+ if (!refname)
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+ die("symref-verify: missing <ref>");
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+
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+ /*
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+ * old_ref is optional, if not provided, we need to ensure that the
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+ * ref doesn't exist.
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+ */
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+ old_target = parse_next_refname(&next);
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+ if (!old_target)
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+ oidcpy(&old_oid, null_oid());
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+
353
+ if (*next != line_termination)
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+ die("symref-verify %s: extra input: %s", refname, next);
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+
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+ if (ref_transaction_verify(transaction, refname,
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+ old_target ? NULL : &old_oid,
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+ old_target, update_flags, &err))
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die("%s", err.buf);
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update_flags = default_flags;
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free(refname);
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+ free(old_target);
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strbuf_release(&err);
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}
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@@ -380,15 +439,16 @@ static const struct parse_cmd {
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unsigned args;
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enum update_refs_state state;
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} command[] = {
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- { "update", parse_cmd_update, 3, UPDATE_REFS_OPEN },
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- { "create", parse_cmd_create, 2, UPDATE_REFS_OPEN },
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- { "delete", parse_cmd_delete, 2, UPDATE_REFS_OPEN },
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- { "verify", parse_cmd_verify, 2, UPDATE_REFS_OPEN },
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- { "option", parse_cmd_option, 1, UPDATE_REFS_OPEN },
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- { "start", parse_cmd_start, 0, UPDATE_REFS_STARTED },
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- { "prepare", parse_cmd_prepare, 0, UPDATE_REFS_PREPARED },
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- { "abort", parse_cmd_abort, 0, UPDATE_REFS_CLOSED },
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- { "commit", parse_cmd_commit, 0, UPDATE_REFS_CLOSED },
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+ { "update", parse_cmd_update, 3, UPDATE_REFS_OPEN },
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+ { "create", parse_cmd_create, 2, UPDATE_REFS_OPEN },
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+ { "delete", parse_cmd_delete, 2, UPDATE_REFS_OPEN },
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+ { "verify", parse_cmd_verify, 2, UPDATE_REFS_OPEN },
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+ { "symref-verify", parse_cmd_symref_verify, 2, UPDATE_REFS_OPEN },
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+ { "option", parse_cmd_option, 1, UPDATE_REFS_OPEN },
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+ { "start", parse_cmd_start, 0, UPDATE_REFS_STARTED },
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+ { "prepare", parse_cmd_prepare, 0, UPDATE_REFS_PREPARED },
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+ { "abort", parse_cmd_abort, 0, UPDATE_REFS_CLOSED },
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+ { "commit", parse_cmd_commit, 0, UPDATE_REFS_CLOSED },
452
};
453
454
static void update_refs_stdin(void)
refs.c
+8
-3
@@ -1331,14 +1331,19 @@ int ref_transaction_delete(struct ref_transaction *transaction,
1331
int ref_transaction_verify(struct ref_transaction *transaction,
1332
const char *refname,
1333
const struct object_id *old_oid,
1334
+ const char *old_target,
1335
unsigned int flags,
1336
struct strbuf *err)
1337
{
1337
- if (!old_oid)
1338
- BUG("verify called with old_oid set to NULL");
1338
+ if (!old_target && !old_oid)
1339
+ BUG("verify called with old_oid and old_target set to NULL");
1340
+ if (old_oid && old_target)
1341
+ BUG("verify called with both old_oid and old_target set");
1342
+ if (old_target && !(flags & REF_NO_DEREF))
1343
+ BUG("verify cannot operate on symrefs with deref mode");
1344
return ref_transaction_update(transaction, refname,
1345
NULL, old_oid,
1341
- NULL, NULL,
1346
+ NULL, old_target,
1347
flags, NULL, err);
1348
}
1349
refs.h
+1
@@ -781,6 +781,7 @@ int ref_transaction_delete(struct ref_transaction *transaction,
781
int ref_transaction_verify(struct ref_transaction *transaction,
782
const char *refname,
783
const struct object_id *old_oid,
784
+ const char *old_target,
785
unsigned int flags,
786
struct strbuf *err);
787
t/t1400-update-ref.sh
+92
-2
@@ -890,17 +890,23 @@ test_expect_success 'stdin update/create/verify combination works' '
890
'
891
892
test_expect_success 'stdin verify succeeds for correct value' '
893
+ test-tool ref-store main for-each-reflog-ent $m >before &&
894
git rev-parse $m >expect &&
895
echo "verify $m $m" >stdin &&
896
git update-ref --stdin <stdin &&
897
git rev-parse $m >actual &&
897
- test_cmp expect actual
898
+ test_cmp expect actual &&
899
+ test-tool ref-store main for-each-reflog-ent $m >after &&
900
+ test_cmp before after
901
'
902
903
test_expect_success 'stdin verify succeeds for missing reference' '
904
+ test-tool ref-store main for-each-reflog-ent $m >before &&
905
echo "verify refs/heads/missing $Z" >stdin &&
906
git update-ref --stdin <stdin &&
903
- test_must_fail git rev-parse --verify -q refs/heads/missing
907
+ test_must_fail git rev-parse --verify -q refs/heads/missing &&
908
+ test-tool ref-store main for-each-reflog-ent $m >after &&
909
+ test_cmp before after
910
'
911
912
test_expect_success 'stdin verify treats no value as missing' '
@@ -1641,4 +1647,88 @@ test_expect_success PIPE 'transaction flushes status updates' '
1647
test_cmp expected actual
1648
'
1649
1650
+format_command () {
1651
+ if test "$1" = "-z"
1652
+ then
1653
+ shift
1654
+ printf "$F" "$@"
1655
+ else
1656
+ echo "$@"
1657
+ fi
1658
+}
1659
+
1660
+for type in "" "-z"
1661
+do
1662
+
1663
+ test_expect_success "stdin $type symref-verify fails without --no-deref" '
1664
+ git symbolic-ref refs/heads/symref $a &&
1665
+ format_command $type "symref-verify refs/heads/symref" "$a" >stdin &&
1666
+ test_must_fail git update-ref --stdin $type <stdin 2>err &&
1667
+ grep "fatal: symref-verify: cannot operate with deref mode" err
1668
+ '
1669
+
1670
+ test_expect_success "stdin $type symref-verify fails with too many arguments" '
1671
+ format_command $type "symref-verify refs/heads/symref" "$a" "$a" >stdin &&
1672
+ test_must_fail git update-ref --stdin $type --no-deref <stdin 2>err &&
1673
+ if test "$type" = "-z"
1674
+ then
1675
+ grep "fatal: unknown command: $a" err
1676
+ else
1677
+ grep "fatal: symref-verify refs/heads/symref: extra input: $a" err
1678
+ fi
1679
+ '
1680
+
1681
+ test_expect_success "stdin $type symref-verify succeeds for correct value" '
1682
+ git symbolic-ref refs/heads/symref >expect &&
1683
+ test-tool ref-store main for-each-reflog-ent refs/heads/symref >before &&
1684
+ format_command $type "symref-verify refs/heads/symref" "$a" >stdin &&
1685
+ git update-ref --stdin $type --no-deref <stdin &&
1686
+ git symbolic-ref refs/heads/symref >actual &&
1687
+ test_cmp expect actual &&
1688
+ test-tool ref-store main for-each-reflog-ent refs/heads/symref >after &&
1689
+ test_cmp before after
1690
+ '
1691
+
1692
+ test_expect_success "stdin $type symref-verify fails with no value" '
1693
+ git symbolic-ref refs/heads/symref >expect &&
1694
+ format_command $type "symref-verify refs/heads/symref" "" >stdin &&
1695
+ test_must_fail git update-ref --stdin $type --no-deref <stdin
1696
+ '
1697
+
1698
+ test_expect_success "stdin $type symref-verify succeeds for dangling reference" '
1699
+ test_when_finished "git symbolic-ref -d refs/heads/symref2" &&
1700
+ test_must_fail git symbolic-ref refs/heads/nonexistent &&
1701
+ git symbolic-ref refs/heads/symref2 refs/heads/nonexistent &&
1702
+ format_command $type "symref-verify refs/heads/symref2" "refs/heads/nonexistent" >stdin &&
1703
+ git update-ref --stdin $type --no-deref <stdin
1704
+ '
1705
+
1706
+ test_expect_success "stdin $type symref-verify fails for missing reference" '
1707
+ test-tool ref-store main for-each-reflog-ent refs/heads/symref >before &&
1708
+ format_command $type "symref-verify refs/heads/missing" "refs/heads/unknown" >stdin &&
1709
+ test_must_fail git update-ref --stdin $type --no-deref <stdin 2>err &&
1710
+ grep "fatal: cannot lock ref ${SQ}refs/heads/missing${SQ}: unable to resolve reference ${SQ}refs/heads/missing${SQ}" err &&
1711
+ test_must_fail git rev-parse --verify -q refs/heads/missing &&
1712
+ test-tool ref-store main for-each-reflog-ent refs/heads/symref >after &&
1713
+ test_cmp before after
1714
+ '
1715
+
1716
+ test_expect_success "stdin $type symref-verify fails for wrong value" '
1717
+ git symbolic-ref refs/heads/symref >expect &&
1718
+ format_command $type "symref-verify refs/heads/symref" "$b" >stdin &&
1719
+ test_must_fail git update-ref --stdin $type --no-deref <stdin &&
1720
+ git symbolic-ref refs/heads/symref >actual &&
1721
+ test_cmp expect actual
1722
+ '
1723
+
1724
+ test_expect_success "stdin $type symref-verify fails for mistaken null value" '
1725
+ git symbolic-ref refs/heads/symref >expect &&
1726
+ format_command $type "symref-verify refs/heads/symref" "$Z" >stdin &&
1727
+ test_must_fail git update-ref --stdin $type --no-deref <stdin &&
1728
+ git symbolic-ref refs/heads/symref >actual &&
1729
+ test_cmp expect actual
1730
+ '
1731
+
1732
+done
1733
+
1734
test_done
t/t1416-ref-transaction-hooks.sh
+30
@@ -157,4 +157,34 @@ test_expect_success 'hook captures git-symbolic-ref updates' '
157
test_cmp expect actual
158
'
159
160
+test_expect_success 'hook gets all queued symref updates' '
161
+ test_when_finished "rm actual" &&
162
+
163
+ git update-ref refs/heads/branch $POST_OID &&
164
+ git symbolic-ref refs/heads/symref refs/heads/main &&
165
+
166
+ test_hook reference-transaction <<-\EOF &&
167
+ echo "$*" >>actual
168
+ while read -r line
169
+ do
170
+ printf "%s\n" "$line"
171
+ done >>actual
172
+ EOF
173
+
174
+ cat >expect <<-EOF &&
175
+ prepared
176
+ ref:refs/heads/main $ZERO_OID refs/heads/symref
177
+ committed
178
+ ref:refs/heads/main $ZERO_OID refs/heads/symref
179
+ EOF
180
+
181
+ git update-ref --no-deref --stdin <<-EOF &&
182
+ start
183
+ symref-verify refs/heads/symref refs/heads/main
184
+ prepare
185
+ commit
186
+ EOF
187
+ test_cmp expect actual
188
+'
189
+
190
test_done