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From: Taylor Blau <me@ttaylorr.com>
To: git@vger.kernel.org
Cc: peff@peff.net, avarab@gmail.com
Subject: [PATCH v2] multi-pack-index: fix potential segfault without sub-command
Date: Wed, 21 Jul 2021 12:52:37 -0400	[thread overview]
Message-ID: <12804130427fd71e88ce10aed283c1f9cdd330ef.1626886330.git.me@ttaylorr.com> (raw)
In-Reply-To: <YPfWkzRtQKthOgZx@coredump.intra.peff.net>

Since cd57bc41bb (builtin/multi-pack-index.c: display usage on
unrecognized command, 2021-03-30) we have used a "usage" label to avoid
having two separate callers of usage_with_options (one when no arguments
are given, and another for unrecognized sub-commands).

But the first caller has been broken since cd57bc41bb, since it will
happily jump to usage without arguments, and then pass argv[0] to the
"unrecognized subcommand" error.

Many compilers will save us from a segfault here, but the end result is
ugly, since it mentions an unrecognized subcommand when we didn't even
pass one, and (on GCC) includes "(null)" in its output.

Move the "usage" label down past the error about unrecognized
subcommands so that it is only triggered when it should be. While we're
at it, bulk up our test coverage in this area, too.

Signed-off-by: Taylor Blau <me@ttaylorr.com>
---
I didn't realize that we are veering away from test_i18ngrep in new
tests, so here's a version of this trivial patch with grep instead.

Range-diff against v1:
1:  8c0bb3e0dc ! 1:  1280413042 multi-pack-index: fix potential segfault without sub-command
    @@ t/t5319-multi-pack-index.sh: test_expect_success 'load reverse index when missin

     +test_expect_success 'usage shown without sub-command' '
     +	test_expect_code 129 git multi-pack-index 2>err &&
    -+	! test_i18ngrep "unrecognized subcommand" err
    ++	! grep "unrecognized subcommand" err
     +'
     +
      test_done

 builtin/multi-pack-index.c  | 2 +-
 t/t5319-multi-pack-index.sh | 5 +++++
 2 files changed, 6 insertions(+), 1 deletion(-)

diff --git a/builtin/multi-pack-index.c b/builtin/multi-pack-index.c
index 5d3ea445fd..8ff0dee2ec 100644
--- a/builtin/multi-pack-index.c
+++ b/builtin/multi-pack-index.c
@@ -176,8 +176,8 @@ int cmd_multi_pack_index(int argc, const char **argv,
 	else if (!strcmp(argv[0], "expire"))
 		return cmd_multi_pack_index_expire(argc, argv);
 	else {
-usage:
 		error(_("unrecognized subcommand: %s"), argv[0]);
+usage:
 		usage_with_options(builtin_multi_pack_index_usage,
 				   builtin_multi_pack_index_options);
 	}
diff --git a/t/t5319-multi-pack-index.sh b/t/t5319-multi-pack-index.sh
index 7609f1ea64..c0ec5a6fd3 100755
--- a/t/t5319-multi-pack-index.sh
+++ b/t/t5319-multi-pack-index.sh
@@ -837,4 +837,9 @@ test_expect_success 'load reverse index when missing .idx, .pack' '
 	)
 '

+test_expect_success 'usage shown without sub-command' '
+	test_expect_code 129 git multi-pack-index 2>err &&
+	! grep "unrecognized subcommand" err
+'
+
 test_done
--
2.31.1.163.ga65ce7f831

  reply	other threads:[~2021-07-21 16:52 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-07-19 17:18 [PATCH] multi-pack-index: fix potential segfault without sub-command Taylor Blau
2021-07-21  8:10 ` Jeff King
2021-07-21 16:52   ` Taylor Blau [this message]
2021-07-23  7:34     ` [PATCH v2] " Jeff King

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