Patrick Steinhardt <ps@xxxxxx> writes:
> When executing git-update-ref(1) with the `--stdin` flag, then the user
> can queue updates and, since e48cf33b61 (update-ref: implement
> interactive transaction handling, 2020-04-02), interactively drive the
> transaction's state via a set of transactional verbs. This interactivity
> is somewhat broken though: while the caller can use these verbs to drive
> the transaction's state, the status messages which confirm that a verb
> has been processed is not flushed. The caller may thus be left hanging
> waiting for the acknowledgement.
>
> Fix the bug by flushing stdout after writing the status update. Add a
> test which catches this bug.
Nobody hit by this for more than a year is interesting.
Will queue. Thanks.
>
> Signed-off-by: Patrick Steinhardt <ps@xxxxxx>
> ---
> builtin/update-ref.c | 14 ++++++++++----
> t/t1400-update-ref.sh | 32 ++++++++++++++++++++++++++++++++
> 2 files changed, 42 insertions(+), 4 deletions(-)
>
> diff --git a/builtin/update-ref.c b/builtin/update-ref.c
> index 6029a80544..a84e7b47a2 100644
> --- a/builtin/update-ref.c
> +++ b/builtin/update-ref.c
> @@ -302,6 +302,12 @@ static void parse_cmd_verify(struct ref_transaction *transaction,
> strbuf_release(&err);
> }
>
> +static void report_ok(const char *command)
> +{
> + fprintf(stdout, "%s: ok\n", command);
> + fflush(stdout);
> +}
> +
> static void parse_cmd_option(struct ref_transaction *transaction,
> const char *next, const char *end)
> {
> @@ -317,7 +323,7 @@ static void parse_cmd_start(struct ref_transaction *transaction,
> {
> if (*next != line_termination)
> die("start: extra input: %s", next);
> - puts("start: ok");
> + report_ok("start");
> }
>
> static void parse_cmd_prepare(struct ref_transaction *transaction,
> @@ -328,7 +334,7 @@ static void parse_cmd_prepare(struct ref_transaction *transaction,
> die("prepare: extra input: %s", next);
> if (ref_transaction_prepare(transaction, &error))
> die("prepare: %s", error.buf);
> - puts("prepare: ok");
> + report_ok("prepare");
> }
>
> static void parse_cmd_abort(struct ref_transaction *transaction,
> @@ -339,7 +345,7 @@ static void parse_cmd_abort(struct ref_transaction *transaction,
> die("abort: extra input: %s", next);
> if (ref_transaction_abort(transaction, &error))
> die("abort: %s", error.buf);
> - puts("abort: ok");
> + report_ok("abort");
> }
>
> static void parse_cmd_commit(struct ref_transaction *transaction,
> @@ -350,7 +356,7 @@ static void parse_cmd_commit(struct ref_transaction *transaction,
> die("commit: extra input: %s", next);
> if (ref_transaction_commit(transaction, &error))
> die("commit: %s", error.buf);
> - puts("commit: ok");
> + report_ok("commit");
> ref_transaction_free(transaction);
> }
>
> diff --git a/t/t1400-update-ref.sh b/t/t1400-update-ref.sh
> index 4506cd435b..1e754e258f 100755
> --- a/t/t1400-update-ref.sh
> +++ b/t/t1400-update-ref.sh
> @@ -1598,6 +1598,38 @@ test_expect_success 'transaction cannot restart ongoing transaction' '
> test_must_fail git show-ref --verify refs/heads/restart
> '
>
> +test_expect_success PIPE 'transaction flushes status updates' '
> + mkfifo in out &&
> + (git update-ref --stdin <in >out &) &&
> +
> + exec 9>in &&
> + test_when_finished "exec 9>&-" &&
> +
> + echo "start" >&9 &&
> + echo "start: ok" >expected &&
> + read line <out &&
> + echo "$line" >actual &&
> + test_cmp expected actual &&
> +
> + echo "create refs/heads/flush $A" >&9 &&
> +
> + echo prepare >&9 &&
> + echo "prepare: ok" >expected &&
> + read line <out &&
> + echo "$line" >actual &&
> + test_cmp expected actual &&
> +
> + # This must now fail given that we have locked the ref.
> + test_must_fail git update-ref refs/heads/flush $B 2>stderr &&
> + grep "fatal: update_ref failed for ref ${SQ}refs/heads/flush${SQ}: cannot lock ref" stderr &&
> +
> + echo commit >&9 &&
> + echo "commit: ok" >expected &&
> + read line <out &&
> + echo "$line" >actual &&
> + test_cmp expected actual
> +'
> +
> test_expect_success 'directory not created deleting packed ref' '
> git branch d1/d2/r1 HEAD &&
> git pack-refs --all &&
