[PULL 1/7] qapi-schema: support alternates with array type

[Markus Armbruster <armbru@redhat.com>]

From: Paolo Bonzini <pbonzini@redhat.com>

Detect array types as alternate branches, and turn the JSON list into
a QAPISchemaArrayType.  Array types in an alternate are represented with
QTYPE_QLIST in the type field.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <20220321164243.200569-2-pbonzini@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
---
 scripts/qapi/expr.py                   |  2 +-
 scripts/qapi/schema.py                 |  4 ++++
 tests/qapi-schema/alternate-array.err  |  2 --
 tests/qapi-schema/alternate-array.json |  2 --
 tests/qapi-schema/alternate-array.out  | 18 ++++++++++++++++++
 5 files changed, 23 insertions(+), 5 deletions(-)

diff --git a/scripts/qapi/expr.py b/scripts/qapi/expr.py
index 3cb389e875..48578e1698 100644
--- a/scripts/qapi/expr.py
+++ b/scripts/qapi/expr.py
@@ -554,7 +554,7 @@ def check_alternate(expr: _JSONObject, info: QAPISourceInfo) -> None:
         check_name_lower(key, info, source)
         check_keys(value, info, source, ['type'], ['if'])
         check_if(value, info, source)
-        check_type(value['type'], info, source)
+        check_type(value['type'], info, source, allow_array=True)
 
 
 def check_command(expr: _JSONObject, info: QAPISourceInfo) -> None:
diff --git a/scripts/qapi/schema.py b/scripts/qapi/schema.py
index b7b3fc0ce4..3728340c37 100644
--- a/scripts/qapi/schema.py
+++ b/scripts/qapi/schema.py
@@ -243,6 +243,7 @@ def alternate_qtype(self):
             'number':  'QTYPE_QNUM',
             'int':     'QTYPE_QNUM',
             'boolean': 'QTYPE_QBOOL',
+            'array':   'QTYPE_QLIST',
             'object':  'QTYPE_QDICT'
         }
         return json2qtype.get(self.json_type())
@@ -1069,6 +1070,9 @@ def _def_struct_type(self, expr, info, doc):
             None))
 
     def _make_variant(self, case, typ, ifcond, info):
+        if isinstance(typ, list):
+            assert len(typ) == 1
+            typ = self._make_array_type(typ[0], info)
         return QAPISchemaVariant(case, info, typ, ifcond)
 
     def _def_union_type(self, expr, info, doc):
diff --git a/tests/qapi-schema/alternate-array.err b/tests/qapi-schema/alternate-array.err
index b1aa1f4e8d..e69de29bb2 100644
--- a/tests/qapi-schema/alternate-array.err
+++ b/tests/qapi-schema/alternate-array.err
@@ -1,2 +0,0 @@
-alternate-array.json: In alternate 'Alt':
-alternate-array.json:5: 'data' member 'two' cannot be an array
diff --git a/tests/qapi-schema/alternate-array.json b/tests/qapi-schema/alternate-array.json
index f241aac122..b878a2db77 100644
--- a/tests/qapi-schema/alternate-array.json
+++ b/tests/qapi-schema/alternate-array.json
@@ -1,5 +1,3 @@
-# we do not allow array branches in alternates
-# TODO: should we support this?
 { 'struct': 'One',
   'data': { 'name': 'str' } }
 { 'alternate': 'Alt',
diff --git a/tests/qapi-schema/alternate-array.out b/tests/qapi-schema/alternate-array.out
index e69de29bb2..a657d85738 100644
--- a/tests/qapi-schema/alternate-array.out
+++ b/tests/qapi-schema/alternate-array.out
@@ -0,0 +1,18 @@
+module ./builtin
+object q_empty
+enum QType
+    prefix QTYPE
+    member none
+    member qnull
+    member qnum
+    member qstring
+    member qdict
+    member qlist
+    member qbool
+module alternate-array.json
+object One
+    member name: str optional=False
+alternate Alt
+    tag type
+    case one: One
+    case two: intList
-- 
2.35.1