Re: [PATCH v2 6/7] config: allow configuration of multiple hook error behavior

From: Duy Nguyen <pclouds@gmail.com>
Date: May 14, 2019, 13:20 UTC
Message-ID: <CACsJy8BN32Jm62MQPLsRwKST8DDNZ7NxnJbsqBO3PJ0K2qU-Ng@mail.gmail.com>
In-Reply-To: <20190514002332.121089-8-sandals@crustytoothpaste.net>

On Tue, May 14, 2019 at 7:24 AM brian m. carlson <sandals@crustytoothpaste.net> wrote:

>
> There are a variety of situations in which a user may want an error
> behavior for multiple hooks other than the default. Add a config option,
> hook.<name>.errorBehavior to allow users to customize this behavior on a

An alternative name is onError, probably more often used for event callbacks. But I don't know, maybe errorBehavior is actually better.

> per-hook basis. Provide options for the default behavior (exiting

should we fall back to hook.errorBehavior? That allows people to set global policy, then customize just a small set of weird hooks.

Show 36 quoted lines

> early), executing all hooks and succeeding if all hooks succeed, or
> executing all hooks and succeeding if any hook succeeds.
> Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
> ---
>  config.c       |  27 +++++++++++++
>  run-command.c  |  42 +++++++++++++++++---
>  run-command.h  |   5 +++
>  t/lib-hooks.sh | 106 ++++++++++++++++++++++++++++++++++++++++++++++++-
>  4 files changed, 173 insertions(+), 7 deletions(-)
>
> diff --git a/config.c b/config.c
> index c2846df3f1..9cba4061a9 100644
> --- a/config.c
> +++ b/config.c
> @@ -19,6 +19,7 @@
>  #include "utf8.h"
>  #include "dir.h"
>  #include "color.h"
> +#include "run-command.h"
>
>  struct config_source {
>         struct config_source *prev;
> @@ -1093,6 +1094,29 @@ int git_config_color(char *dest, const char *var, const char *value)
>         return 0;
>  }
>
> +static int git_default_hook_config(const char *key, const char *value)
> +{
> +       const char *hook;
> +       size_t key_len;
> +       uintptr_t behavior;
> +
> +       key += strlen("hook.");
> +       if (strip_suffix(key, ".errorbehavior", &key_len)) {
> +               hook = xmemdupz(key, key_len);
> +               if (!strcmp(value, "stop-on-first"))

maybe stop-on-first-error (or if you go with the "onError" name, I think "stop" is enough). I know "stop on/after first hook" does not really make any sense when you think about it. Maybe stop-on-first is sufficient.

I was going to suggest strcasecmp. But core.whitespace (also has multiple-word-values) already sets a precedent on strcmp. I think we're good. Or mostly good, I don't know, we still accept False, false and FALSE.

> +                       behavior = HOOK_ERROR_STOP_ON_FIRST;

This is basically the logical "and" behavior in a C expression. Which makes me think if anybody's crazy enough to need the "or" counterpart (i.e. run hooks, expect failure, keep going until the first success).

I guess it's a crazy mode. We should not care about until a real use case shows up.

> +               else if (!strcmp(value, "report-any-error"))

I couldn't guess based on this name alone, whether we continue or stop after the reporting part. The 7/7 document makes it clear though. So all good.

Show 9 quoted lines

> diff --git a/run-command.c b/run-command.c
> index 191d6f6f7e..70fb19a55b 100644
> --- a/run-command.c
> +++ b/run-command.c
> @@ -1308,6 +1308,8 @@ int async_with_fork(void)
>  #endif
>  }
>
> +struct string_list hook_error_behavior = STRING_LIST_INIT_NODUP;

Maybe stick this in 'struct repository'. I know most config variables are still global. But I think we have to move/reorganize them at some point. Most may end up in 'struct repository'.

Show 44 quoted lines

> @@ -1401,18 +1403,48 @@ int for_each_hook(const char *name,
>                   void *data)
>  {
>         struct string_list paths = STRING_LIST_INIT_DUP;
> -       int i, ret = 0;
> +       int i, hret = 0;
> +       uintptr_t behavior = HOOK_ERROR_STOP_ON_FIRST;
> +       struct string_list_item *item;
> +       /* Use -2 as sentinel because failure to exec is -1. */
> +       int ret = -2;
> +
> +       item = string_list_lookup(&hook_error_behavior, name);
> +       if (item)
> +               behavior = (uintptr_t)item->util;
>
>         find_hooks(name, &paths);
>         for (i = 0; i < paths.nr; i++) {
>                 const char *p = paths.items[i].string;
>
> -               ret = handler(name, p, data);
> -               if (ret)
> -                       break;
> +               hret = handler(name, p, data);
> +               switch (behavior) {
> +                       case HOOK_ERROR_STOP_ON_FIRST:
> +                               if (hret) {
> +                                       ret = hret;
> +                                       goto out;
> +                               }
> +                               break;
> +                       case HOOK_ERROR_REPORT_ANY_SUCCESS:
> +                               if (ret == -2)
> +                                       ret = 1;
> +                               if (!hret)
> +                                       ret = 0;
> +                               break;
> +                       case HOOK_ERROR_REPORT_ANY_ERROR:
> +                               if (ret == -2)
> +                                       ret = 0;
> +                               if (hret)
> +                                       ret = hret;
> +                               break;
> +                       default:
> +                               BUG("unknown hook error behavior");

maybe BUG(".. behavior %d", behavior);

Show 10 quoted lines

> +               }
>         }
> -
> +out:
>         string_list_clear(&paths, 0);
> +       if (ret == -2)
> +               return 0;
>         return ret;
>  }
>

-- 
Duy