update-ref: add support for 'symref-update' command
Add 'symref-update' command to the '--stdin' mode of 'git-update-ref' to allow updates of symbolic refs. The 'symref-update' command takes in a <new-target>, which the <ref> will be updated to. If the <ref> doesn't exist it will be created. It also optionally takes either an `ref <old-target>` or `oid <old-oid>`. If the <old-target> is provided, it checks to see if the <ref> targets the <old-target> before the update. If <old-oid> is provided it checks <ref> to ensure that it is a regular ref and <old-oid> is the OID before the update. This by extension also means that this when a zero <old-oid> is provided, it ensures that the ref didn't exist before. The divergence in syntax from the regular `update` command is because if we don't use a `(ref | oid)` prefix for the old_value, then there is ambiguity around if the value provided should be treated as an oid or a reference. This is more so the reason, because we allow anything committish to be provided as an oid. While 'symref-verify' and 'symref-delete' also take in `<old-target>` we do not have this divergence there as those commands only work with symrefs. Whereas 'symref-update' also works with regular refs and allows users to convert regular refs to symrefs. The command allows users to perform symbolic ref updates within a transaction. This provides atomicity and allows users to perform a set of operations together. This command supports deref mode, to ensure that we can update dereferenced regular refs to symrefs. Helped-by: Patrick Steinhardt <ps@pks.im> Helped-by: Junio C Hamano <gitster@pobox.com> 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
7dd4051b014741732271785c0915599b1f0c1a47
4 files changed
+306
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
67
verify SP <ref> [SP <old-oid>] LF
68
+ symref-update SP <ref> SP <new-target> [SP (ref SP <old-target> | oid SP <old-oid>)] LF
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symref-create SP <ref> SP <new-target> LF
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symref-delete SP <ref> [SP <old-target>] LF
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symref-verify SP <ref> [SP <old-target>] LF
@@ -89,6 +90,7 @@ quoting:
90
create SP <ref> NUL <new-oid> NUL
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delete SP <ref> NUL [<old-oid>] NUL
92
verify SP <ref> NUL [<old-oid>] NUL
93
+ symref-update SP <ref> NUL <new-target> [NUL (ref NUL <old-target> | oid NUL <old-oid>)] NUL
94
symref-create SP <ref> NUL <new-target> NUL
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symref-delete SP <ref> [NUL <old-target>] NUL
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symref-verify SP <ref> [NUL <old-target>] NUL
@@ -119,6 +121,11 @@ delete::
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Delete <ref> after verifying it exists with <old-oid>, if
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given. If given, <old-oid> may not be zero.
123
124
+symref-update::
125
+ Set <ref> to <new-target> after verifying <old-target> or <old-oid>,
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+ if given. Specify a zero <old-oid> to ensure that the ref does not
127
+ exist before the update.
128
+
129
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.
builtin/update-ref.c
+92
@@ -98,6 +98,42 @@ static char *parse_next_refname(const char **next)
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return parse_refname(next);
99
}
100
101
+/*
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+ * Wrapper around parse_arg which skips the next delimiter.
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+ */
104
+static char *parse_next_arg(const char **next)
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+{
106
+ struct strbuf arg = STRBUF_INIT;
107
+
108
+ 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;
112
+ if (**next != ' ')
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+ die("expected SP but got: %s", *next);
114
+ } 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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+ }
119
+ /* Skip the delimiter */
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+ (*next)++;
121
+
122
+ if (line_termination) {
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+ /* Without -z, use the next argument */
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+ *next = parse_arg(*next, &arg);
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+ } else {
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+ /* With -z, use everything up to the next NUL */
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+ strbuf_addstr(&arg, *next);
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+ *next += arg.len;
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+ }
130
+
131
+ if (arg.len)
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+ return strbuf_detach(&arg, NULL);
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+
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+ strbuf_release(&arg);
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+ return NULL;
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+}
137
138
/*
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* The value being parsed is <old-oid> (as opposed to <new-oid>; the
@@ -237,6 +273,61 @@ static void parse_cmd_update(struct ref_transaction *transaction,
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strbuf_release(&err);
274
}
275
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+static void parse_cmd_symref_update(struct ref_transaction *transaction,
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+ const char *next, const char *end)
278
+{
279
+ char *refname, *new_target, *old_arg;
280
+ char *old_target = NULL;
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+ struct strbuf err = STRBUF_INIT;
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+ struct object_id old_oid;
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+ int have_old_oid = 0;
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+
285
+ refname = parse_refname(&next);
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+ if (!refname)
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+ die("symref-update: missing <ref>");
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+
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+ new_target = parse_next_refname(&next);
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+ if (!new_target)
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+ die("symref-update %s: missing <new-target>", refname);
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+
293
+ old_arg = parse_next_arg(&next);
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+ if (old_arg) {
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+ old_target = parse_next_arg(&next);
296
+ if (!old_target)
297
+ die("symref-update %s: expected old value", refname);
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+
299
+ if (!strcmp(old_arg, "oid")) {
300
+ if (repo_get_oid(the_repository, old_target, &old_oid))
301
+ die("symref-update %s: invalid oid: %s", refname, old_target);
302
+
303
+ have_old_oid = 1;
304
+ } else if (!strcmp(old_arg, "ref")) {
305
+ if (check_refname_format(old_target, REFNAME_ALLOW_ONELEVEL))
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+ die("symref-update %s: invalid ref: %s", refname, old_target);
307
+ } else {
308
+ die("symref-update %s: invalid arg '%s' for old value", refname, old_arg);
309
+ }
310
+ }
311
+
312
+ if (*next != line_termination)
313
+ die("symref-update %s: extra input: %s", refname, next);
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+
315
+ if (ref_transaction_update(transaction, refname, NULL,
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+ have_old_oid ? &old_oid : NULL,
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+ new_target,
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+ have_old_oid ? NULL : old_target,
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+ update_flags | create_reflog_flag,
320
+ msg, &err))
321
+ die("%s", err.buf);
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+
323
+ update_flags = default_flags;
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+ free(refname);
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+ free(old_arg);
326
+ free(old_target);
327
+ free(new_target);
328
+ strbuf_release(&err);
329
+}
330
+
331
static void parse_cmd_create(struct ref_transaction *transaction,
332
const char *next, const char *end)
333
{
@@ -502,6 +593,7 @@ static const struct parse_cmd {
593
{ "create", parse_cmd_create, 2, UPDATE_REFS_OPEN },
594
{ "delete", parse_cmd_delete, 2, UPDATE_REFS_OPEN },
595
{ "verify", parse_cmd_verify, 2, UPDATE_REFS_OPEN },
596
+ { "symref-update", parse_cmd_symref_update, 4, UPDATE_REFS_OPEN },
597
{ "symref-create", parse_cmd_symref_create, 2, UPDATE_REFS_OPEN },
598
{ "symref-delete", parse_cmd_symref_delete, 2, UPDATE_REFS_OPEN },
599
{ "symref-verify", parse_cmd_symref_verify, 2, UPDATE_REFS_OPEN },
t/t1400-update-ref.sh
+203
@@ -1360,6 +1360,7 @@ test_expect_success 'fails with duplicate HEAD update' '
1360
'
1361
1362
test_expect_success 'fails with duplicate ref update via symref' '
1363
+ test_when_finished "git symbolic-ref -d refs/heads/symref2" &&
1364
git branch target2 $A &&
1365
git symbolic-ref refs/heads/symref2 refs/heads/target2 &&
1366
cat >stdin <<-EOF &&
@@ -1862,6 +1863,208 @@ do
1863
git reflog exists refs/heads/symref
1864
'
1865
1866
+ test_expect_success "stdin $type symref-update fails with too many arguments" '
1867
+ format_command $type "symref-update refs/heads/symref" "$a" "ref" "$a" "$a" >stdin &&
1868
+ test_must_fail git update-ref --stdin $type --no-deref <stdin 2>err &&
1869
+ if test "$type" = "-z"
1870
+ then
1871
+ grep "fatal: unknown command: $a" err
1872
+ else
1873
+ grep "fatal: symref-update refs/heads/symref: extra input: $a" err
1874
+ fi
1875
+ '
1876
+
1877
+ test_expect_success "stdin $type symref-update fails with wrong old value argument" '
1878
+ format_command $type "symref-update refs/heads/symref" "$a" "foo" "$a" "$a" >stdin &&
1879
+ test_must_fail git update-ref --stdin $type --no-deref <stdin 2>err &&
1880
+ grep "fatal: symref-update refs/heads/symref: invalid arg ${SQ}foo${SQ} for old value" err
1881
+ '
1882
+
1883
+ test_expect_success "stdin $type symref-update creates with zero old value" '
1884
+ test_when_finished "git symbolic-ref -d refs/heads/symref" &&
1885
+ format_command $type "symref-update refs/heads/symref" "$a" "oid" "$Z" >stdin &&
1886
+ git update-ref --stdin $type --no-deref <stdin &&
1887
+ echo $a >expect &&
1888
+ git symbolic-ref refs/heads/symref >actual &&
1889
+ test_cmp expect actual
1890
+ '
1891
+
1892
+ test_expect_success "stdin $type symref-update creates with no old value" '
1893
+ test_when_finished "git symbolic-ref -d refs/heads/symref" &&
1894
+ format_command $type "symref-update refs/heads/symref" "$a" >stdin &&
1895
+ git update-ref --stdin $type --no-deref <stdin &&
1896
+ echo $a >expect &&
1897
+ git symbolic-ref refs/heads/symref >actual &&
1898
+ test_cmp expect actual
1899
+ '
1900
+
1901
+ test_expect_success "stdin $type symref-update creates dangling" '
1902
+ test_when_finished "git symbolic-ref -d refs/heads/symref" &&
1903
+ test_must_fail git rev-parse refs/heads/nonexistent &&
1904
+ format_command $type "symref-update refs/heads/symref" "refs/heads/nonexistent" >stdin &&
1905
+ git update-ref --stdin $type --no-deref <stdin &&
1906
+ echo refs/heads/nonexistent >expect &&
1907
+ git symbolic-ref refs/heads/symref >actual &&
1908
+ test_cmp expect actual
1909
+ '
1910
+
1911
+ test_expect_success "stdin $type symref-update fails with wrong old value" '
1912
+ test_when_finished "git symbolic-ref -d refs/heads/symref" &&
1913
+ git symbolic-ref refs/heads/symref $a &&
1914
+ format_command $type "symref-update refs/heads/symref" "$m" "ref" "$b" >stdin &&
1915
+ test_must_fail git update-ref --stdin $type --no-deref <stdin 2>err &&
1916
+ grep "fatal: verifying symref target: ${SQ}refs/heads/symref${SQ}: is at $a but expected $b" err &&
1917
+ test_must_fail git rev-parse --verify -q $c
1918
+ '
1919
+
1920
+ test_expect_success "stdin $type symref-update updates dangling ref" '
1921
+ test_when_finished "git symbolic-ref -d refs/heads/symref" &&
1922
+ test_must_fail git rev-parse refs/heads/nonexistent &&
1923
+ git symbolic-ref refs/heads/symref refs/heads/nonexistent &&
1924
+ format_command $type "symref-update refs/heads/symref" "$a" >stdin &&
1925
+ git update-ref --stdin $type --no-deref <stdin &&
1926
+ echo $a >expect &&
1927
+ git symbolic-ref refs/heads/symref >actual &&
1928
+ test_cmp expect actual
1929
+ '
1930
+
1931
+ test_expect_success "stdin $type symref-update updates dangling ref with old value" '
1932
+ test_when_finished "git symbolic-ref -d refs/heads/symref" &&
1933
+ test_must_fail git rev-parse refs/heads/nonexistent &&
1934
+ git symbolic-ref refs/heads/symref refs/heads/nonexistent &&
1935
+ format_command $type "symref-update refs/heads/symref" "$a" "ref" "refs/heads/nonexistent" >stdin &&
1936
+ git update-ref --stdin $type --no-deref <stdin &&
1937
+ echo $a >expect &&
1938
+ git symbolic-ref refs/heads/symref >actual &&
1939
+ test_cmp expect actual
1940
+ '
1941
+
1942
+ test_expect_success "stdin $type symref-update fails update dangling ref with wrong old value" '
1943
+ test_when_finished "git symbolic-ref -d refs/heads/symref" &&
1944
+ test_must_fail git rev-parse refs/heads/nonexistent &&
1945
+ git symbolic-ref refs/heads/symref refs/heads/nonexistent &&
1946
+ format_command $type "symref-update refs/heads/symref" "$a" "ref" "refs/heads/wrongref" >stdin &&
1947
+ test_must_fail git update-ref --stdin $type --no-deref <stdin &&
1948
+ echo refs/heads/nonexistent >expect &&
1949
+ git symbolic-ref refs/heads/symref >actual &&
1950
+ test_cmp expect actual
1951
+ '
1952
+
1953
+ test_expect_success "stdin $type symref-update works with right old value" '
1954
+ test_when_finished "git symbolic-ref -d refs/heads/symref" &&
1955
+ git symbolic-ref refs/heads/symref $a &&
1956
+ format_command $type "symref-update refs/heads/symref" "$m" "ref" "$a" >stdin &&
1957
+ git update-ref --stdin $type --no-deref <stdin &&
1958
+ echo $m >expect &&
1959
+ git symbolic-ref refs/heads/symref >actual &&
1960
+ test_cmp expect actual
1961
+ '
1962
+
1963
+ test_expect_success "stdin $type symref-update works with no old value" '
1964
+ test_when_finished "git symbolic-ref -d refs/heads/symref" &&
1965
+ git symbolic-ref refs/heads/symref $a &&
1966
+ format_command $type "symref-update refs/heads/symref" "$m" >stdin &&
1967
+ git update-ref --stdin $type --no-deref <stdin &&
1968
+ echo $m >expect &&
1969
+ git symbolic-ref refs/heads/symref >actual &&
1970
+ test_cmp expect actual
1971
+ '
1972
+
1973
+ test_expect_success "stdin $type symref-update fails with empty old ref-target" '
1974
+ test_when_finished "git symbolic-ref -d refs/heads/symref" &&
1975
+ git symbolic-ref refs/heads/symref $a &&
1976
+ format_command $type "symref-update refs/heads/symref" "$m" "ref" "" >stdin &&
1977
+ test_must_fail git update-ref --stdin $type --no-deref <stdin &&
1978
+ echo $a >expect &&
1979
+ git symbolic-ref refs/heads/symref >actual &&
1980
+ test_cmp expect actual
1981
+ '
1982
+
1983
+ test_expect_success "stdin $type symref-update creates (with deref)" '
1984
+ test_when_finished "git symbolic-ref -d refs/heads/symref" &&
1985
+ format_command $type "symref-update refs/heads/symref" "$a" >stdin &&
1986
+ git update-ref --stdin $type <stdin &&
1987
+ echo $a >expect &&
1988
+ git symbolic-ref --no-recurse refs/heads/symref >actual &&
1989
+ test_cmp expect actual &&
1990
+ test-tool ref-store main for-each-reflog-ent refs/heads/symref >actual &&
1991
+ grep "$Z $(git rev-parse $a)" actual
1992
+ '
1993
+
1994
+ test_expect_success "stdin $type symref-update regular ref to symref with correct old-oid" '
1995
+ test_when_finished "git symbolic-ref -d --no-recurse refs/heads/regularref" &&
1996
+ git update-ref --no-deref refs/heads/regularref $a &&
1997
+ format_command $type "symref-update refs/heads/regularref" "$a" "oid" "$(git rev-parse $a)" >stdin &&
1998
+ git update-ref --stdin $type <stdin &&
1999
+ echo $a >expect &&
2000
+ git symbolic-ref --no-recurse refs/heads/regularref >actual &&
2001
+ test_cmp expect actual &&
2002
+ test-tool ref-store main for-each-reflog-ent refs/heads/regularref >actual &&
2003
+ grep "$(git rev-parse $a) $(git rev-parse $a)" actual
2004
+ '
2005
+
2006
+ test_expect_success "stdin $type symref-update regular ref to symref fails with wrong old-oid" '
2007
+ test_when_finished "git update-ref -d refs/heads/regularref" &&
2008
+ git update-ref --no-deref refs/heads/regularref $a &&
2009
+ format_command $type "symref-update refs/heads/regularref" "$a" "oid" "$(git rev-parse refs/heads/target2)" >stdin &&
2010
+ test_must_fail git update-ref --stdin $type <stdin 2>err &&
2011
+ grep "fatal: cannot lock ref ${SQ}refs/heads/regularref${SQ}: is at $(git rev-parse $a) but expected $(git rev-parse refs/heads/target2)" err &&
2012
+ echo $(git rev-parse $a) >expect &&
2013
+ git rev-parse refs/heads/regularref >actual &&
2014
+ test_cmp expect actual
2015
+ '
2016
+
2017
+ test_expect_success "stdin $type symref-update regular ref to symref fails with invalid old-oid" '
2018
+ test_when_finished "git update-ref -d refs/heads/regularref" &&
2019
+ git update-ref --no-deref refs/heads/regularref $a &&
2020
+ format_command $type "symref-update refs/heads/regularref" "$a" "oid" "not-a-ref-oid" >stdin &&
2021
+ test_must_fail git update-ref --stdin $type <stdin 2>err &&
2022
+ grep "fatal: symref-update refs/heads/regularref: invalid oid: not-a-ref-oid" err &&
2023
+ echo $(git rev-parse $a) >expect &&
2024
+ git rev-parse refs/heads/regularref >actual &&
2025
+ test_cmp expect actual
2026
+ '
2027
+
2028
+ test_expect_success "stdin $type symref-update existing symref with zero old-oid" '
2029
+ test_when_finished "git symbolic-ref -d --no-recurse refs/heads/symref" &&
2030
+ git symbolic-ref refs/heads/symref refs/heads/target2 &&
2031
+ format_command $type "symref-update refs/heads/symref" "$a" "oid" "$Z" >stdin &&
2032
+ test_must_fail git update-ref --stdin $type <stdin 2>err &&
2033
+ grep "fatal: cannot lock ref ${SQ}refs/heads/symref${SQ}: reference already exists" err &&
2034
+ echo refs/heads/target2 >expect &&
2035
+ git symbolic-ref refs/heads/symref >actual &&
2036
+ test_cmp expect actual
2037
+ '
2038
+
2039
+ test_expect_success "stdin $type symref-update regular ref to symref (with deref)" '
2040
+ test_when_finished "git symbolic-ref -d refs/heads/symref" &&
2041
+ test_when_finished "git update-ref -d --no-deref refs/heads/symref2" &&
2042
+ git update-ref refs/heads/symref2 $a &&
2043
+ git symbolic-ref --no-recurse refs/heads/symref refs/heads/symref2 &&
2044
+ format_command $type "symref-update refs/heads/symref" "$a" >stdin &&
2045
+ git update-ref $type --stdin <stdin &&
2046
+ echo $a >expect &&
2047
+ git symbolic-ref --no-recurse refs/heads/symref2 >actual &&
2048
+ test_cmp expect actual &&
2049
+ echo refs/heads/symref2 >expect &&
2050
+ git symbolic-ref --no-recurse refs/heads/symref >actual &&
2051
+ test_cmp expect actual &&
2052
+ test-tool ref-store main for-each-reflog-ent refs/heads/symref >actual &&
2053
+ grep "$(git rev-parse $a) $(git rev-parse $a)" actual
2054
+ '
2055
+
2056
+ test_expect_success "stdin $type symref-update regular ref to symref" '
2057
+ test_when_finished "git symbolic-ref -d --no-recurse refs/heads/regularref" &&
2058
+ git update-ref --no-deref refs/heads/regularref $a &&
2059
+ format_command $type "symref-update refs/heads/regularref" "$a" >stdin &&
2060
+ git update-ref $type --stdin <stdin &&
2061
+ echo $a >expect &&
2062
+ git symbolic-ref --no-recurse refs/heads/regularref >actual &&
2063
+ test_cmp expect actual &&
2064
+ test-tool ref-store main for-each-reflog-ent refs/heads/regularref >actual &&
2065
+ grep "$(git rev-parse $a) $(git rev-parse $a)" actual
2066
+ '
2067
+
2068
done
2069
2070
test_done
t/t1416-ref-transaction-hooks.sh
+4
@@ -163,6 +163,7 @@ test_expect_success 'hook gets all queued symref updates' '
163
git update-ref refs/heads/branch $POST_OID &&
164
git symbolic-ref refs/heads/symref refs/heads/main &&
165
git symbolic-ref refs/heads/symrefd refs/heads/main &&
166
+ git symbolic-ref refs/heads/symrefu refs/heads/main &&
167
168
test_hook reference-transaction <<-\EOF &&
169
echo "$*" >>actual
@@ -190,10 +191,12 @@ test_expect_success 'hook gets all queued symref updates' '
191
ref:refs/heads/main $ZERO_OID refs/heads/symref
192
ref:refs/heads/main $ZERO_OID refs/heads/symrefd
193
$ZERO_OID ref:refs/heads/main refs/heads/symrefc
194
+ ref:refs/heads/main ref:refs/heads/branch refs/heads/symrefu
195
committed
196
ref:refs/heads/main $ZERO_OID refs/heads/symref
197
ref:refs/heads/main $ZERO_OID refs/heads/symrefd
198
$ZERO_OID ref:refs/heads/main refs/heads/symrefc
199
+ ref:refs/heads/main ref:refs/heads/branch refs/heads/symrefu
200
EOF
201
202
git update-ref --no-deref --stdin <<-EOF &&
@@ -201,6 +204,7 @@ test_expect_success 'hook gets all queued symref updates' '
204
symref-verify refs/heads/symref refs/heads/main
205
symref-delete refs/heads/symrefd refs/heads/main
206
symref-create refs/heads/symrefc refs/heads/main
207
+ symref-update refs/heads/symrefu refs/heads/branch ref refs/heads/main
208
prepare
209
commit
210
EOF