Re: bug found on the new git maintenance builtin command

[Derrick Stolee <stolee@gmail.com>]

On 9/14/2020 3:49 PM, Rafael Silva wrote:
> Hi Everyone,
> 
> I found a minor bug when testing the new maintenance built-in command that was
> introduced on 679768e2a1 (maintenance: create basic maintenance runner, 2020-08-25) submitted in [1]

Thank you for identifying the original patch! My gut reaction was that
this is just in the Part III code which adds subcommands, but that is
incorrect.

> (gdb) list
> 1628    int cmd_maintenance(int argc, const char **argv, const char *prefix)
> 1629    {
> 1630        if (argc == 2 && !strcmp(argv[1], "-h"))
> 1631            usage(builtin_maintenance_usage);
> 1632
> 1633        fprintf(stdout, "run");
> 1634        if (!strcmp(argv[1], "run"))
> 1635            return maintenance_run(argc - 1, argv + 1, prefix);
> 1636        if (!strcmp(argv[1], "start"))
> 1637            return maintenance_start();
> (gdb) print argc
> $5 = 1
> (gdb) print argv[1]
> $6 = 0x0
> 
> Hope all this information helps with the fixing it

Thank you so much for the report!

The patch below applies to ds/maintenance-part-1, to fix the problem.
Hopefully it also merges cleanly with the changes in ds/maintenance-part-3,
but I can deal with that when I submit my next re-roll.

Thanks!
-Stolee

-- >8 --

From 8cd793e16cd8521f4f8d7ccf2b93492ba444e8e7 Mon Sep 17 00:00:00 2001
From: Derrick Stolee <dstolee@microsoft.com>
Date: Mon, 14 Sep 2020 16:42:36 -0400
Subject: [PATCH] maintenance: correctly handle missing subcommand

The maintenance builtin created in 679768e2a12 (maintenance: create
basic maintenance runner, 2020-08-25) has a flaw in that it does not
protect against a user running "git maintenance" without any additional
parameters. Correct this by adding a check on argc before looking for
the -h option.

Reported-by: Rafael Silva <rafaeloliveira.cs@gmail.com>
Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
---
 builtin/gc.c           | 3 ++-
 t/t7900-maintenance.sh | 4 +++-
 2 files changed, 5 insertions(+), 2 deletions(-)

diff --git a/builtin/gc.c b/builtin/gc.c
index c3bcdc1167a..090959350e0 100644
--- a/builtin/gc.c
+++ b/builtin/gc.c
@@ -1027,7 +1027,8 @@ static const char builtin_maintenance_usage[] = N_("git maintenance run [<option
 
 int cmd_maintenance(int argc, const char **argv, const char *prefix)
 {
-	if (argc == 2 && !strcmp(argv[1], "-h"))
+	if (argc < 2 ||
+	    (argc == 2 && !strcmp(argv[1], "-h")))
 		usage(builtin_maintenance_usage);
 
 	if (!strcmp(argv[1], "run"))
diff --git a/t/t7900-maintenance.sh b/t/t7900-maintenance.sh
index 4f6a04ddb1e..53c883531e4 100755
--- a/t/t7900-maintenance.sh
+++ b/t/t7900-maintenance.sh
@@ -10,7 +10,9 @@ test_expect_success 'help text' '
 	test_expect_code 129 git maintenance -h 2>err &&
 	test_i18ngrep "usage: git maintenance run" err &&
 	test_expect_code 128 git maintenance barf 2>err &&
-	test_i18ngrep "invalid subcommand: barf" err
+	test_i18ngrep "invalid subcommand: barf" err &&
+	test_expect_code 129 git maintenance 2>err &&
+	test_i18ngrep "usage: git maintenance" err
 '
 
 test_expect_success 'run [--auto|--quiet]' '
-- 
2.28.0.vfs.0.0