Max Reitz <mre...@redhat.com> writes:
> Optional discriminators are fine, as long as there is a default value.
>
> Signed-off-by: Max Reitz <mre...@redhat.com>
> ---
> scripts/qapi/common.py | 14 ++++++++++++--
> 1 file changed, 12 insertions(+), 2 deletions(-)
>
> diff --git a/scripts/qapi/common.py b/scripts/qapi/common.py
> index 8c57d0c67a..203623795b 100644
> --- a/scripts/qapi/common.py
> +++ b/scripts/qapi/common.py
> @@ -1052,11 +1052,21 @@ def check_union(expr, info):
> base_members = find_base_members(base)
> assert base_members is not None
>
> - # The value of member 'discriminator' must name a non-optional
> - # member of the base struct.
> + # The value of member 'discriminator' must name a member of
> + # the base struct. (Optional members are allowed, but the
> + # discriminator name must not start with '*', so keep
> + # allow_optional=False.)
> check_name(info, "Discriminator of flat union '%s'" % name,
> discriminator)
> +
> discriminator_value = base_members.get(discriminator)
> + if not discriminator_value:
> + discriminator_value = base_members.get('*' + discriminator)
> + if discriminator_value and 'default' not in discriminator_value:
> + raise QAPISemError(info,
> + "Optional discriminator '%s' has no default value" %
> + discriminator)
> +
> if not discriminator_value:
> raise QAPISemError(info,
> "Discriminator '%s' is not a member of base "
Needs test coverage and doc update.
Oh, looks like later patches provide. Please consider squashing. Doc
updates and tests often make code changes easier to understand.
