diff options
| author | Markus Armbruster <armbru@redhat.com> | 2019-09-13 22:13:42 +0200 |
|---|---|---|
| committer | Markus Armbruster <armbru@redhat.com> | 2019-09-24 14:07:22 +0200 |
| commit | f03255362ae3bfd6f105c0fc855c713944f99717 (patch) | |
| tree | 82cf6ddf03b23e7556833f4c52500730d35aa737 /scripts/qapi/common.py | |
| parent | 675b214bc6ba2c1d8ac499e339a8cb99c7f23c7c (diff) | |
qapi: Permit alternates with just one branch
A union or alternate without branches makes no sense and doesn't work:
it can't be instantiated. A union or alternate with just one branch
works, but is degenerate. We accept the former, but reject the
latter. Weird. docs/devel/qapi-code-gen.txt doesn't mention the
difference. It claims an alternate definition is "is similar to a
simple union type".
Permit degenerate alternates to make them consistent with unions.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20190913201349.24332-10-armbru@redhat.com>
Diffstat (limited to 'scripts/qapi/common.py')
| -rw-r--r-- | scripts/qapi/common.py | 6 |
1 files changed, 2 insertions, 4 deletions
diff --git a/scripts/qapi/common.py b/scripts/qapi/common.py index c5c71287c3..99db18f3d6 100644 --- a/scripts/qapi/common.py +++ b/scripts/qapi/common.py @@ -920,11 +920,9 @@ def check_alternate(expr, info): members = expr['data'] types_seen = {} - # Check every branch; require at least two branches - if len(members) < 2: + if len(members) == 0: raise QAPISemError(info, - "Alternate '%s' should have at least two branches " - "in 'data'" % name) + "Alternate '%s' cannot have empty 'data'" % name) for (key, value) in members.items(): check_name(info, "Member of alternate '%s'" % name, key) check_known_keys(info, |