update-ref: add support for 'symref-delete' command
Add a new command 'symref-delete' to allow deletions of symbolic refs in a transaction via the '--stdin' mode of the 'git-update-ref' command. The 'symref-delete' command can, when given an <old-target>, delete the provided <ref> only when it points to <old-target>. This command is only compatible with the 'no-deref' mode because we optionally want to check the 'old_target' of the ref being deleted. De-referencing a symbolic ref would provide a regular ref and we already have the 'delete' command for regular refs. While users can also use 'git symbolic-ref -d' to delete symbolic refs, the 'symref-delete' command in 'git-update-ref' allows users to do so within a transaction, which promises atomicity of the operation and can be batched with other commands. When no 'old_target' is provided it can also delete regular refs, similar to how the 'delete' command can delete symrefs when no 'old_oid' is provided. 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
2343720967aac3725148e1a6690dbe6c98fe5f2e
8 files changed
+140
-10
Documentation/git-update-ref.txt
+5
@@ -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
68
+ symref-delete SP <ref> [SP <old-target>] LF
69
symref-verify SP <ref> [SP <old-target>] LF
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option SP <opt> LF
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start LF
@@ -87,6 +88,7 @@ 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-delete SP <ref> [NUL <old-target>] 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
@@ -119,6 +121,9 @@ 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.
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+symref-delete::
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+ Delete <ref> after verifying it exists with <old-target>, if given.
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+
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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
builtin/fetch.c
+2
-2
@@ -1382,8 +1382,8 @@ static int prune_refs(struct display_state *display_state,
1382
if (!dry_run) {
1383
if (transaction) {
1384
for (ref = stale_refs; ref; ref = ref->next) {
1385
- result = ref_transaction_delete(transaction, ref->name, NULL, 0,
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- "fetch: prune", &err);
1385
+ result = ref_transaction_delete(transaction, ref->name, NULL,
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+ NULL, 0, "fetch: prune", &err);
1387
if (result)
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goto cleanup;
1389
}
builtin/receive-pack.c
+2
-1
@@ -1576,7 +1576,8 @@ static const char *update(struct command *cmd, struct shallow_info *si)
1576
if (ref_transaction_delete(transaction,
1577
namespaced_name,
1578
old_oid,
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- 0, "push", &err)) {
1579
+ NULL, 0,
1580
+ "push", &err)) {
1581
rp_error("%s", err.buf);
1582
ret = "failed to delete";
1583
} else {
builtin/update-ref.c
+32
-1
@@ -293,7 +293,7 @@ static void parse_cmd_delete(struct ref_transaction *transaction,
293
294
if (ref_transaction_delete(transaction, refname,
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have_old ? &old_oid : NULL,
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- update_flags, msg, &err))
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+ NULL, update_flags, msg, &err))
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die("%s", err.buf);
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update_flags = default_flags;
@@ -301,6 +301,36 @@ static void parse_cmd_delete(struct ref_transaction *transaction,
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strbuf_release(&err);
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}
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304
+
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+static void parse_cmd_symref_delete(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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+ char *refname, *old_target;
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+
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+ if (!(update_flags & REF_NO_DEREF))
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+ die("symref-delete: 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-delete: missing <ref>");
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+
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+ old_target = parse_next_refname(&next);
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+
320
+ if (*next != line_termination)
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+ die("symref-delete %s: extra input: %s", refname, next);
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+
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+ if (ref_transaction_delete(transaction, refname, NULL,
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+ old_target, update_flags, msg, &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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+ free(old_target);
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+ strbuf_release(&err);
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+}
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+
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+
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static void parse_cmd_verify(struct ref_transaction *transaction,
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const char *next, const char *end)
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{
@@ -443,6 +473,7 @@ static const struct parse_cmd {
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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-delete", parse_cmd_symref_delete, 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 },
refs.c
+10
-4
@@ -979,7 +979,7 @@ int refs_delete_ref(struct ref_store *refs, const char *msg,
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transaction = ref_store_transaction_begin(refs, &err);
980
if (!transaction ||
981
ref_transaction_delete(transaction, refname, old_oid,
982
- flags, msg, &err) ||
982
+ NULL, flags, msg, &err) ||
983
ref_transaction_commit(transaction, &err)) {
984
error("%s", err.buf);
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ref_transaction_free(transaction);
@@ -1317,14 +1317,20 @@ int ref_transaction_create(struct ref_transaction *transaction,
1317
int ref_transaction_delete(struct ref_transaction *transaction,
1318
const char *refname,
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const struct object_id *old_oid,
1320
- unsigned int flags, const char *msg,
1320
+ const char *old_target,
1321
+ unsigned int flags,
1322
+ const char *msg,
1323
struct strbuf *err)
1324
{
1325
if (old_oid && is_null_oid(old_oid))
1326
BUG("delete called with old_oid set to zeros");
1327
+ if (old_oid && old_target)
1328
+ BUG("delete called with both old_oid and old_target set");
1329
+ if (old_target && !(flags & REF_NO_DEREF))
1330
+ BUG("delete cannot operate on symrefs with deref mode");
1331
return ref_transaction_update(transaction, refname,
1332
null_oid(), old_oid,
1327
- NULL, NULL, flags,
1333
+ NULL, old_target, flags,
1334
msg, err);
1335
}
1336
@@ -2767,7 +2773,7 @@ int refs_delete_refs(struct ref_store *refs, const char *logmsg,
2773
2774
for_each_string_list_item(item, refnames) {
2775
ret = ref_transaction_delete(transaction, item->string,
2770
- NULL, flags, msg, &err);
2776
+ NULL, NULL, flags, msg, &err);
2777
if (ret) {
2778
warning(_("could not delete reference %s: %s"),
2779
item->string, err.buf);
refs.h
+3
-1
@@ -767,7 +767,9 @@ int ref_transaction_create(struct ref_transaction *transaction,
767
int ref_transaction_delete(struct ref_transaction *transaction,
768
const char *refname,
769
const struct object_id *old_oid,
770
- unsigned int flags, const char *msg,
770
+ const char *old_target,
771
+ unsigned int flags,
772
+ const char *msg,
773
struct strbuf *err);
774
775
/*
t/t1400-update-ref.sh
+68
@@ -1729,6 +1729,74 @@ do
1729
test_cmp expect actual
1730
'
1731
1732
+ test_expect_success "stdin $type symref-delete fails without --no-deref" '
1733
+ git symbolic-ref refs/heads/symref $a &&
1734
+ format_command $type "symref-delete refs/heads/symref" "$a" >stdin &&
1735
+ test_must_fail git update-ref --stdin $type <stdin 2>err &&
1736
+ grep "fatal: symref-delete: cannot operate with deref mode" err
1737
+ '
1738
+
1739
+ test_expect_success "stdin $type symref-delete fails with no ref" '
1740
+ format_command $type "symref-delete " >stdin &&
1741
+ test_must_fail git update-ref --stdin $type --no-deref <stdin 2>err &&
1742
+ grep "fatal: symref-delete: missing <ref>" err
1743
+ '
1744
+
1745
+ test_expect_success "stdin $type symref-delete fails deleting regular ref" '
1746
+ test_when_finished "git update-ref -d refs/heads/regularref" &&
1747
+ git update-ref refs/heads/regularref $a &&
1748
+ format_command $type "symref-delete refs/heads/regularref" "$a" >stdin &&
1749
+ test_must_fail git update-ref --stdin $type --no-deref <stdin 2>err &&
1750
+ grep "fatal: cannot lock ref ${SQ}refs/heads/regularref${SQ}: expected symref with target ${SQ}$a${SQ}: but is a regular ref" err
1751
+ '
1752
+
1753
+ test_expect_success "stdin $type symref-delete fails with too many arguments" '
1754
+ format_command $type "symref-delete refs/heads/symref" "$a" "$a" >stdin &&
1755
+ test_must_fail git update-ref --stdin $type --no-deref <stdin 2>err &&
1756
+ if test "$type" = "-z"
1757
+ then
1758
+ grep "fatal: unknown command: $a" err
1759
+ else
1760
+ grep "fatal: symref-delete refs/heads/symref: extra input: $a" err
1761
+ fi
1762
+ '
1763
+
1764
+ test_expect_success "stdin $type symref-delete fails with wrong old value" '
1765
+ format_command $type "symref-delete refs/heads/symref" "$m" >stdin &&
1766
+ test_must_fail git update-ref --stdin $type --no-deref <stdin 2>err &&
1767
+ grep "fatal: verifying symref target: ${SQ}refs/heads/symref${SQ}: is at $a but expected refs/heads/main" err &&
1768
+ git symbolic-ref refs/heads/symref >expect &&
1769
+ echo $a >actual &&
1770
+ test_cmp expect actual
1771
+ '
1772
+
1773
+ test_expect_success "stdin $type symref-delete works with right old value" '
1774
+ format_command $type "symref-delete refs/heads/symref" "$a" >stdin &&
1775
+ git update-ref --stdin $type --no-deref <stdin &&
1776
+ test_must_fail git rev-parse --verify -q refs/heads/symref
1777
+ '
1778
+
1779
+ test_expect_success "stdin $type symref-delete works with empty old value" '
1780
+ git symbolic-ref refs/heads/symref $a >stdin &&
1781
+ format_command $type "symref-delete refs/heads/symref" "" >stdin &&
1782
+ git update-ref --stdin $type --no-deref <stdin &&
1783
+ test_must_fail git rev-parse --verify -q $b
1784
+ '
1785
+
1786
+ test_expect_success "stdin $type symref-delete succeeds for dangling reference" '
1787
+ test_must_fail git symbolic-ref refs/heads/nonexistent &&
1788
+ git symbolic-ref refs/heads/symref2 refs/heads/nonexistent &&
1789
+ format_command $type "symref-delete refs/heads/symref2" "refs/heads/nonexistent" >stdin &&
1790
+ git update-ref --stdin $type --no-deref <stdin &&
1791
+ test_must_fail git symbolic-ref -d refs/heads/symref2
1792
+ '
1793
+
1794
+ test_expect_success "stdin $type symref-delete deletes regular ref without target" '
1795
+ git update-ref refs/heads/regularref $a &&
1796
+ format_command $type "symref-delete refs/heads/regularref" >stdin &&
1797
+ git update-ref --stdin $type --no-deref <stdin
1798
+ '
1799
+
1800
done
1801
1802
test_done
t/t1416-ref-transaction-hooks.sh
+18
-1
@@ -162,6 +162,7 @@ test_expect_success 'hook gets all queued symref updates' '
162
163
git update-ref refs/heads/branch $POST_OID &&
164
git symbolic-ref refs/heads/symref refs/heads/main &&
165
+ git symbolic-ref refs/heads/symrefd refs/heads/main &&
166
167
test_hook reference-transaction <<-\EOF &&
168
echo "$*" >>actual
@@ -171,16 +172,32 @@ test_expect_success 'hook gets all queued symref updates' '
172
done >>actual
173
EOF
174
174
- cat >expect <<-EOF &&
175
+ # In the files backend, "delete" also triggers an additional transaction
176
+ # update on the packed-refs backend, which constitutes additional reflog
177
+ # entries.
178
+ if test_have_prereq REFFILES
179
+ then
180
+ cat >expect <<-EOF
181
+ aborted
182
+ $ZERO_OID $ZERO_OID refs/heads/symrefd
183
+ EOF
184
+ else
185
+ >expect
186
+ fi &&
187
+
188
+ cat >>expect <<-EOF &&
189
prepared
190
ref:refs/heads/main $ZERO_OID refs/heads/symref
191
+ ref:refs/heads/main $ZERO_OID refs/heads/symrefd
192
committed
193
ref:refs/heads/main $ZERO_OID refs/heads/symref
194
+ ref:refs/heads/main $ZERO_OID refs/heads/symrefd
195
EOF
196
197
git update-ref --no-deref --stdin <<-EOF &&
198
start
199
symref-verify refs/heads/symref refs/heads/main
200
+ symref-delete refs/heads/symrefd refs/heads/main
201
prepare
202
commit
203
EOF