+1 -2

docs/devel/qapi-code-gen.txt

··· 436 436 variants for an object. There are two flavors: simple (no 437 437 discriminator or base), and flat (both discriminator and base). A union 438 438 type is defined using a data dictionary as explained in the following 439 439 - paragraphs. The data dictionary for either type of union must not 440 440 - be empty. 439 439 + paragraphs. Unions must have at least one branch. 441 440 442 441 A simple union type defines a mapping from automatic discriminator 443 442 values to data types like in this example:

+8 -8

scripts/qapi/common.py

··· 852 852 853 853 # With no discriminator it is a simple union. 854 854 if discriminator is None: 855 855 - enum_define = None 855 855 + enum_values = members.keys() 856 856 allow_metas = ['built-in', 'union', 'alternate', 'struct', 'enum'] 857 857 if base is not None: 858 858 raise QAPISemError(info, "Simple union '%s' must not have a base" % ··· 885 885 'must not be conditional' % 886 886 (base, discriminator, name)) 887 887 enum_define = enum_types.get(discriminator_value['type']) 888 888 - allow_metas = ['struct'] 889 888 # Do not allow string discriminator 890 889 if not enum_define: 891 890 raise QAPISemError(info, 892 891 "Discriminator '%s' must be of enumeration " 893 892 "type" % discriminator) 893 893 + enum_values = enum_get_names(enum_define) 894 894 + allow_metas = ['struct'] 894 895 895 895 - # Check every branch; don't allow an empty union 896 896 - if len(members) == 0: 897 897 - raise QAPISemError(info, "Union '%s' cannot have empty 'data'" % name) 896 896 + if (len(enum_values) == 0): 897 897 + raise QAPISemError(info, "Union '%s' has no branches" % name) 898 898 + 898 899 for (key, value) in members.items(): 899 900 check_name(info, "Member of union '%s'" % name, key) 900 901 ··· 907 908 908 909 # If the discriminator names an enum type, then all members 909 910 # of 'data' must also be members of the enum type. 910 910 - if enum_define: 911 911 - if key not in enum_get_names(enum_define): 911 911 + if discriminator is not None: 912 912 + if key not in enum_values: 912 913 raise QAPISemError(info, 913 914 "Discriminator value '%s' is not found in " 914 915 "enum '%s'" ··· 1578 1579 assert bool(tag_member) != bool(tag_name) 1579 1580 assert (isinstance(tag_name, str) or 1580 1581 isinstance(tag_member, QAPISchemaObjectTypeMember)) 1581 1581 - assert len(variants) > 0 1582 1582 for v in variants: 1583 1583 assert isinstance(v, QAPISchemaObjectTypeVariant) 1584 1584 self._tag_name = tag_name

+1 -1

tests/qapi-schema/flat-union-empty.err

··· 1 1 - tests/qapi-schema/flat-union-empty.json:4: Union 'Union' cannot have empty 'data' 1 1 + tests/qapi-schema/flat-union-empty.json:4: Union 'Union' has no branches

+1 -1

tests/qapi-schema/flat-union-empty.json

··· 1 1 - # flat unions cannot be empty 1 1 + # flat union discriminator cannot be empty 2 2 { 'enum': 'Empty', 'data': [ ] } 3 3 { 'struct': 'Base', 'data': { 'type': 'Empty' } } 4 4 { 'union': 'Union', 'base': 'Base', 'discriminator': 'type', 'data': { } }

+5

tests/qapi-schema/qapi-schema-test.json

··· 25 25 { 'struct': 'Empty1', 'data': { } } 26 26 { 'struct': 'Empty2', 'base': 'Empty1', 'data': { } } 27 27 28 28 + # Likewise for an empty flat union 29 29 + { 'union': 'Union', 30 30 + 'base': { 'type': 'EnumOne' }, 'discriminator': 'type', 31 31 + 'data': { } } 32 32 + 28 33 { 'command': 'user_def_cmd0', 'data': 'Empty2', 'returns': 'Empty2' } 29 34 30 35 # for testing override of default naming heuristic

+9

tests/qapi-schema/qapi-schema-test.out

··· 23 23 object Empty1 24 24 object Empty2 25 25 base Empty1 26 26 + object q_obj_Union-base 27 27 + member type: EnumOne optional=False 28 28 + object Union 29 29 + base q_obj_Union-base 30 30 + tag type 31 31 + case value1: q_empty 32 32 + case value2: q_empty 33 33 + case value3: q_empty 34 34 + case value4: q_empty 26 35 command user_def_cmd0 Empty2 -> Empty2 27 36 gen=True success_response=True boxed=False oob=False preconfig=False 28 37 enum QEnumTwo

+1 -1

tests/qapi-schema/union-empty.err

··· 1 1 - tests/qapi-schema/union-empty.json:2: Union 'Union' cannot have empty 'data' 1 1 + tests/qapi-schema/union-empty.json:2: Union 'Union' has no branches

+1 -1

tests/qapi-schema/union-empty.json

··· 1 1 - # unions cannot be empty 1 1 + # simple unions cannot be empty 2 2 { 'union': 'Union', 'data': { } }