Re: [PATCH v2 1/4] test-tool: help verifying BUG() code paths

From: Duy Nguyen <pclouds@gmail.com>
Date: May 2, 2018, 15:18 UTC
Message-ID: <CACsJy8D+h+7BXSs1cggRP_UQc5qvtu6ZtrtLiBcu-qLeTpz3Yg@mail.gmail.com>
In-Reply-To: <6e2bfd3a6eb5270c809262f046e6a8b80090b352.1525253892.git.johannes.schindelin@gmx.de>

On Wed, May 2, 2018 at 11:38 AM, Johannes Schindelin <johannes.schindelin@gmx.de> wrote:

Show 31 quoted lines

> When we call BUG(), we signal via SIGABRT that something bad happened,
> dumping cores if so configured. In some setups these coredumps are
> redirected to some central place such as /proc/sys/kernel/core_pattern,
> which is a good thing.
>
> However, when we try to verify in our test suite that bugs are caught in
> certain code paths, we do *not* want to clutter such a central place
> with unnecessary coredumps.
>
> So let's special-case the test helpers (which we use to verify such code
> paths) so that the BUG() calls will *not* call abort() but exit with a
> special-purpose exit code instead.
>
> Helped-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
> Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
> ---
>  t/helper/test-tool.c | 2 ++
>  usage.c              | 5 +++++
>  2 files changed, 7 insertions(+)
>
> diff --git a/t/helper/test-tool.c b/t/helper/test-tool.c
> index 87066ced62a..5176f9f20ae 100644
> --- a/t/helper/test-tool.c
> +++ b/t/helper/test-tool.c
> @@ -47,7 +47,9 @@ static struct test_cmd cmds[] = {
>  int cmd_main(int argc, const char **argv)
>  {
>         int i;
> +       extern int BUG_exit_code;
>
> +       BUG_exit_code = 99;

It may be even better to let individual tests in t1406 control this, pretty much like your original patch, except that we tell usage.c to not send SIGABRT and just return a special fault code. That way we don't accidentally suppress BUG()'s sigabrt behavior in tests that do not anticipate it (even in t1406).

But this patch is ok for me too if you don't want another reroll.

Show 30 quoted lines

>         if (argc < 2)
>                 die("I need a test name!");
>
> diff --git a/usage.c b/usage.c
> index cdd534c9dfc..9c84dccfa97 100644
> --- a/usage.c
> +++ b/usage.c
> @@ -210,6 +210,9 @@ void warning(const char *warn, ...)
>         va_end(params);
>  }
>
> +/* Only set this, ever, from t/helper/, when verifying that bugs are caught. */
> +int BUG_exit_code;
> +
>  static NORETURN void BUG_vfl(const char *file, int line, const char *fmt, va_list params)
>  {
>         char prefix[256];
> @@ -221,6 +224,8 @@ static NORETURN void BUG_vfl(const char *file, int line, const char *fmt, va_lis
>                 snprintf(prefix, sizeof(prefix), "BUG: ");
>
>         vreportf(prefix, fmt, params);
> +       if (BUG_exit_code)
> +               exit(BUG_exit_code);
>         abort();
>  }
>
> --
> 2.17.0.windows.1.36.gdf4ca5fb72a
>
>

-- 
Duy