Re: [GSoC][PATCH v2 5/7] sequencer: add a new function to silence a command, except if it fails.

> This adds a new function, run_command_silent_on_success(), to
> redirect the stdout and stderr of a command to a strbuf, and then to run
> that command. This strbuf is printed only if the command fails. It is
> functionnaly similar to output() from git-rebase.sh.
>
> run_git_commit() is then refactored to use of
> run_command_silent_on_success().
>
> Signed-off-by: Alban Gruin <alban.gruin@gmail.com>
> ---
>  sequencer.c | 49 ++++++++++++++++++++++++-------------------------
>  1 file changed, 24 insertions(+), 25 deletions(-)
>
> diff --git a/sequencer.c b/sequencer.c
> index 57fd58bc1..9e2b34a49 100644
> --- a/sequencer.c
> +++ b/sequencer.c
> @@ -768,6 +768,24 @@ N_("you have staged changes in your working tree\n"
>  #define VERIFY_MSG  (1<<4)
>  #define CREATE_ROOT_COMMIT (1<<5)
>  
> +static int run_command_silent_on_success(struct child_process *cmd)
> +{
> +	struct strbuf buf = STRBUF_INIT;
> +	int rc;
> +
> +	cmd->stdout_to_stderr = 1;
> +	rc = pipe_command(cmd,
> +			  NULL, 0,
> +			  /* stdout is already redirected */