diff mbox series

[v4,4/4] update-ref: disallow "start" for ongoing transactions

Message ID d50088345979abab14b7ab755866b78ef63f6d56.1605254957.git.ps@pks.im (mailing list archive)
State Accepted
Commit 8c4417f1cf3c78955a7ea942cc0c8a97e7c77e77
Headers show
Series update-ref: allow creation of multiple transactions | expand

Commit Message

Patrick Steinhardt Nov. 13, 2020, 8:12 a.m. UTC
It is currently possible to write multiple "start" commands into
git-update-ref(1) for a single session, but none of them except for the
first one actually have any effect.

Using such nested "start"s may eventually have a sensible effect. One
may imagine that it restarts the current transaction, effectively
emptying it and creating a new one. It may also allow for creation of
nested transactions. But currently, none of these are implemented.

Silently ignoring this misuse is making it hard to iterate in the future
if "start" is ever going to have meaningful semantics in such a context.
This commit thus makes sure to error out in case we see such use.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
---
 builtin/update-ref.c  |  2 ++
 t/t1400-update-ref.sh | 11 +++++++++++
 2 files changed, 13 insertions(+)
diff mbox series

Patch

diff --git a/builtin/update-ref.c b/builtin/update-ref.c
index bb65129012..6029a80544 100644
--- a/builtin/update-ref.c
+++ b/builtin/update-ref.c
@@ -436,6 +436,8 @@  static void update_refs_stdin(void)
 		switch (state) {
 		case UPDATE_REFS_OPEN:
 		case UPDATE_REFS_STARTED:
+			if (state == UPDATE_REFS_STARTED && cmd->state == UPDATE_REFS_STARTED)
+				die("cannot restart ongoing transaction");
 			/* Do not downgrade a transaction to a non-transaction. */
 			if (cmd->state >= state)
 				state = cmd->state;
diff --git a/t/t1400-update-ref.sh b/t/t1400-update-ref.sh
index 3144e98b31..31b64be521 100755
--- a/t/t1400-update-ref.sh
+++ b/t/t1400-update-ref.sh
@@ -1583,4 +1583,15 @@  test_expect_success 'transaction can commit after abort' '
 	test_cmp expect actual
 '
 
+test_expect_success 'transaction cannot restart ongoing transaction' '
+	cat >stdin <<-EOF &&
+	start
+	create refs/heads/restart $A
+	start
+	commit
+	EOF
+	test_must_fail git update-ref --stdin <stdin >actual &&
+	test_must_fail git show-ref --verify refs/heads/restart
+'
+
 test_done