qapi script: do not allow string discriminator

Since enum based discriminators provide better type-safety and
ensure that future qapi additions do not forget to adjust dependent
unions, forbid using string as discriminator from now on.

Signed-off-by: Wenchao Xia <wenchaoqemu@gmail.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>

6 files changed, 28 insertions, 5 deletions

diff --git a/tests/qapi-schema/flat-union-string-discriminator.err b/tests/qapi-schema/flat-union-string-discriminator.err
new file mode 100644
index 0000000000..87482704ec
--- /dev/null
+++ b/tests/qapi-schema/flat-union-string-discriminator.err
@@ -0,0 +1 @@
+<stdin>:13: Discriminator 'kind' must be of enumeration type
diff --git a/tests/qapi-schema/flat-union-string-discriminator.exit b/tests/qapi-schema/flat-union-string-discriminator.exit
new file mode 100644
index 0000000000..d00491fd7e
--- /dev/null
+++ b/tests/qapi-schema/flat-union-string-discriminator.exit
@@ -0,0 +1 @@
+1
diff --git a/tests/qapi-schema/flat-union-string-discriminator.json b/tests/qapi-schema/flat-union-string-discriminator.json
new file mode 100644
index 0000000000..e966aeb395
--- /dev/null
+++ b/tests/qapi-schema/flat-union-string-discriminator.json
@@ -0,0 +1,17 @@
+{ 'enum': 'TestEnum',
+  'data': [ 'value1', 'value2' ] }
+
+{ 'type': 'TestBase',
+  'data': { 'enum1': 'TestEnum', 'kind': 'str' } }
+
+{ 'type': 'TestTypeA',
+  'data': { 'string': 'str' } }
+
+{ 'type': 'TestTypeB',
+  'data': { 'integer': 'int' } }
+
+{ 'union': 'TestUnion',
+  'base': 'TestBase',
+  'discriminator': 'kind',
+  'data': { 'kind1': 'TestTypeA',
+            'kind2': 'TestTypeB' } }
diff --git a/tests/qapi-schema/flat-union-string-discriminator.out b/tests/qapi-schema/flat-union-string-discriminator.out
new file mode 100644
index 0000000000..e69de29bb2
--- /dev/null
+++ b/tests/qapi-schema/flat-union-string-discriminator.out
diff --git a/tests/qapi-schema/qapi-schema-test.json b/tests/qapi-schema/qapi-schema-test.json
index 471ba47dde..818c06dc75 100644
--- a/tests/qapi-schema/qapi-schema-test.json
+++ b/tests/qapi-schema/qapi-schema-test.json
@@ -37,10 +37,13 @@
   'base': 'UserDefZero',
   'data': { 'a' : 'UserDefA', 'b' : 'UserDefB' } }
 
+{ 'type': 'UserDefUnionBase',
+  'data': { 'string': 'str', 'enum1': 'EnumOne' } }
+
 { 'union': 'UserDefFlatUnion',
-  'base': 'UserDefOne',
-  'discriminator': 'string',
-  'data': { 'a' : 'UserDefA', 'b' : 'UserDefB' } }
+  'base': 'UserDefUnionBase',
+  'discriminator': 'enum1',
+  'data': { 'value1' : 'UserDefA', 'value2' : 'UserDefB', 'value3' : 'UserDefB' } }
 # FIXME generated struct UserDefFlatUnion has members for direct base
 # UserDefOne, but lacks members for indirect base UserDefZero
 
diff --git a/tests/qapi-schema/qapi-schema-test.out b/tests/qapi-schema/qapi-schema-test.out
index 01685d4a46..6cd03f31c3 100644
--- a/tests/qapi-schema/qapi-schema-test.out
+++ b/tests/qapi-schema/qapi-schema-test.out
@@ -7,7 +7,8 @@
  OrderedDict([('type', 'UserDefA'), ('data', OrderedDict([('boolean', 'bool')]))]),
  OrderedDict([('type', 'UserDefB'), ('data', OrderedDict([('integer', 'int')]))]),
  OrderedDict([('union', 'UserDefUnion'), ('base', 'UserDefZero'), ('data', OrderedDict([('a', 'UserDefA'), ('b', 'UserDefB')]))]),
- OrderedDict([('union', 'UserDefFlatUnion'), ('base', 'UserDefOne'), ('discriminator', 'string'), ('data', OrderedDict([('a', 'UserDefA'), ('b', 'UserDefB')]))]),
+ OrderedDict([('type', 'UserDefUnionBase'), ('data', OrderedDict([('string', 'str'), ('enum1', 'EnumOne')]))]),
+ OrderedDict([('union', 'UserDefFlatUnion'), ('base', 'UserDefUnionBase'), ('discriminator', 'enum1'), ('data', OrderedDict([('value1', 'UserDefA'), ('value2', 'UserDefB'), ('value3', 'UserDefB')]))]),
  OrderedDict([('union', 'UserDefAnonUnion'), ('discriminator', OrderedDict()), ('data', OrderedDict([('uda', 'UserDefA'), ('s', 'str'), ('i', 'int')]))]),
  OrderedDict([('union', 'UserDefNativeListUnion'), ('data', OrderedDict([('integer', ['int']), ('s8', ['int8']), ('s16', ['int16']), ('s32', ['int32']), ('s64', ['int64']), ('u8', ['uint8']), ('u16', ['uint16']), ('u32', ['uint32']), ('u64', ['uint64']), ('number', ['number']), ('boolean', ['bool']), ('string', ['str'])]))]),
  OrderedDict([('command', 'user_def_cmd'), ('data', OrderedDict())]),
@@ -17,7 +18,6 @@
  OrderedDict([('type', 'UserDefOptions'), ('data', OrderedDict([('*i64', ['int']), ('*u64', ['uint64']), ('*u16', ['uint16']), ('*i64x', 'int'), ('*u64x', 'uint64')]))])]
 [{'enum_name': 'EnumOne', 'enum_values': ['value1', 'value2', 'value3']},
  {'enum_name': 'UserDefUnionKind', 'enum_values': None},
- {'enum_name': 'UserDefFlatUnionKind', 'enum_values': None},
  {'enum_name': 'UserDefAnonUnionKind', 'enum_values': None},
  {'enum_name': 'UserDefNativeListUnionKind', 'enum_values': None}]
 [OrderedDict([('type', 'NestedEnumsOne'), ('data', OrderedDict([('enum1', 'EnumOne'), ('*enum2', 'EnumOne'), ('enum3', 'EnumOne'), ('*enum4', 'EnumOne')]))]),
@@ -27,4 +27,5 @@
  OrderedDict([('type', 'UserDefNested'), ('data', OrderedDict([('string0', 'str'), ('dict1', OrderedDict([('string1', 'str'), ('dict2', OrderedDict([('userdef1', 'UserDefOne'), ('string2', 'str')])), ('*dict3', OrderedDict([('userdef2', 'UserDefOne'), ('string3', 'str')]))]))]))]),
  OrderedDict([('type', 'UserDefA'), ('data', OrderedDict([('boolean', 'bool')]))]),
  OrderedDict([('type', 'UserDefB'), ('data', OrderedDict([('integer', 'int')]))]),
+ OrderedDict([('type', 'UserDefUnionBase'), ('data', OrderedDict([('string', 'str'), ('enum1', 'EnumOne')]))]),
  OrderedDict([('type', 'UserDefOptions'), ('data', OrderedDict([('*i64', ['int']), ('*u64', ['uint64']), ('*u16', ['uint16']), ('*i64x', 'int'), ('*u64x', 'uint64')]))])]