Marc-André Lureau <marcandre.lur...@redhat.com> writes:
> QDev options accept '?' or 'help' in the list of parameters, which is
> really handy to list the available options.
>
> Unfortunately, this isn't built in QemuOpts. qemu_opts_parse_noisily()
> seems to be the common path for command line options, so place a
> fallback to check for '?' and print help listing available options.
My immediate reaction was "how come this doesn't break -device help"?
It doesn't, because...
> This is very handy, for example with qemu "-spice ?".
>
> Signed-off-by: Marc-André Lureau <marcandre.lur...@redhat.com>
> ---
> util/qemu-option.c | 7 ++++++-
> 1 file changed, 6 insertions(+), 1 deletion(-)
>
> diff --git a/util/qemu-option.c b/util/qemu-option.c
> index 01886efe90..8839ee6523 100644
> --- a/util/qemu-option.c
> +++ b/util/qemu-option.c
> @@ -889,7 +889,12 @@ QemuOpts *qemu_opts_parse_noisily(QemuOptsList *list,
> const char *params,
>
> opts = opts_parse(list, params, permit_abbrev, false, &err);
> if (err) {
> - error_report_err(err);
> + if (has_help_option(params)) {
> + qemu_opts_print_help(list);
> + error_free(err);
> + } else {
> + error_report_err(err);
> + }
> }
> return opts;
> }
... it only kicks in when parsing failed, and it doesn't for option
argument "help".
However, it *can* break for some option arguments:
$ upstream-qemu -device e1000,id=@
upstream-qemu: -device e1000,id=@: Parameter 'id' expects an identifier
Identifiers consist of letters, digits, '-', '.', '_', starting with a
letter.
[Exit 1 ]
$ upstream-qemu -device e1000,id=@,help
[Exit 1 ]
In the second test case, the error message gets replaced by (empty)
help.
I love patches improving help, but I can't immediately see how to
salvage this one.
