Re: [PATCH] perf record: Remove the '--(null)' long_name for --list-opts

[Ingo Molnar <mingo@kernel.org>]

* Yunlong Song <yunlong.song@huawei.com> wrote:

> If the long_name of a 'struct option' is defined as NULL, --list-opts
> will incorrectly print '--(null)' in its output. As a result, '--(null)'
> will finally appear in the case of bash completion, e.g. 'perf record --'.
> 
> Example:
> 
> Before this patch:
> 
>  $ perf record --list-opts
> 
>  --event --filter --pid --tid --realtime --no-buffering --raw-samples
>  --all-cpus --cpu --count --output --no-inherit --freq --mmap-pages
>  --group --(null) --call-graph --verbose --quiet --stat --data
>  --timestamp --period --no-samples --no-buildid-cache --no-buildid
>  --cgroup --delay --uid --branch-any --branch-filter --weight
>  --transaction --per-thread --intr-regs
> 
> After this patch:
> 
>  $ perf record --list-opts
> 
>  --event --filter --pid --tid --realtime --no-buffering --raw-samples
>  --all-cpus --cpu --count --output --no-inherit --freq --mmap-pages
>  --group --call-graph --verbose --quiet --stat --data --timestamp
>  --period --no-samples --no-buildid-cache --no-buildid --cgroup --delay
>  --uid --branch-any --branch-filter --weight --transaction --per-thread
>  --intr-regs
> 
> Signed-off-by: Yunlong Song <yunlong.song@huawei.com>
> ---
>  tools/perf/util/parse-options.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/tools/perf/util/parse-options.c b/tools/perf/util/parse-options.c
> index 4ee9a86..2bfe0b3 100644
> --- a/tools/perf/util/parse-options.c
> +++ b/tools/perf/util/parse-options.c
> @@ -505,7 +505,8 @@ int parse_options_subcommand(int argc, const char **argv, const struct option *o
>  		break;
>  	case PARSE_OPT_LIST_OPTS:
>  		while (options->type != OPTION_END) {
> -			printf("--%s ", options->long_name);
> +			if (options->long_name)
> +				printf("--%s ", options->long_name);

There seems to be another 'perf record --list-opts' bug as 
well:

comet:~/tip> perf record --list-opts
--event --filter --pid --tid --realtime --no-buffering 
--raw-samples --all-cpus --cpu --count --output 
--no-inherit --freq --mmap-pages --group --(null) 
--call-graph --verbose --quiet --stat --data --timestamp 
--period --no-samples --no-buildid-cache --no-buildid 
--cgroup --delay --uid --branch-any --branch-filter 
--weight --transaction --per-thread --intr-regs comet:~/tip> 

Note the lack of newline at the end of the printout.

Thanks,

	Ingo