[11/26] qapi: add 'if' condition on alternate variant

diff --git a/scripts/qapi.py b/scripts/qapi.py
index 333a5c0d1e..7f0d56fb01 100644
--- a/scripts/qapi.py
+++ b/scripts/qapi.py
@@ -829,6 +829,8 @@  def check_alternate(expr, info):
         check_type(info, "Member '%s' of alternate '%s'" % (key, name),
                    value,
                    allow_metas=['built-in', 'union', 'struct', 'enum'])
+        if isinstance(value, dict):
+            value = value['type']
         qtype = find_alternate_member_qtype(value)
         if not qtype:
             raise QAPISemError(info, "Alternate '%s' member '%s' cannot use "
@@ -1643,7 +1645,11 @@  class QAPISchema(object):
                          expr.get('if'))
 
     def _make_variant(self, case, typ):
-        return QAPISchemaObjectTypeVariant(case, typ)
+        ifcond = None
+        if isinstance(typ, dict):
+            ifcond = typ.get('if')
+            typ = typ['type']
+        return QAPISchemaObjectTypeVariant(case, typ, ifcond)
 
     def _make_simple_variant(self, case, typ, info):
         ifcond = None
diff --git a/scripts/qapi-introspect.py b/scripts/qapi-introspect.py
index a867ea5de1..cac5a6a392 100644
--- a/scripts/qapi-introspect.py
+++ b/scripts/qapi-introspect.py
@@ -162,7 +162,7 @@  const QLitObject %(c_name)s = %(c_string)s;
 
     def visit_alternate_type(self, name, info, variants, ifcond):
         self._gen_qlit(name, 'alternate',
-                       {'members': [{'type': self._use_type(m.type)}
+                       {'members': [({'type': self._use_type(m.type)}, m.ifcond)
                                     for m in variants.variants]}, ifcond)
 
     def visit_command(self, name, info, arg_type, ret_type,
diff --git a/tests/Makefile.include b/tests/Makefile.include
index 816cc5c5e3..9462deb02b 100644
--- a/tests/Makefile.include
+++ b/tests/Makefile.include
@@ -351,6 +351,7 @@  qapi-schema += alternate-conflict-dict.json
 qapi-schema += alternate-conflict-enum-bool.json
 qapi-schema += alternate-conflict-enum-int.json
 qapi-schema += alternate-conflict-string.json
+qapi-schema += alternate-dict-invalid.json
 qapi-schema += alternate-empty.json
 qapi-schema += alternate-nested.json
 qapi-schema += alternate-unknown.json
diff --git a/tests/qapi-schema/alternate-dict-invalid.err b/tests/qapi-schema/alternate-dict-invalid.err
new file mode 100644
index 0000000000..707c40f0f6
--- /dev/null
+++ b/tests/qapi-schema/alternate-dict-invalid.err
@@ -0,0 +1 @@ 
+tests/qapi-schema/alternate-dict-invalid.json:2: Member 'two' of alternate 'Alt' should be a type name
diff --git a/tests/qapi-schema/alternate-dict-invalid.exit b/tests/qapi-schema/alternate-dict-invalid.exit
new file mode 100644
index 0000000000..d00491fd7e
--- /dev/null
+++ b/tests/qapi-schema/alternate-dict-invalid.exit
@@ -0,0 +1 @@ 
+1
diff --git a/tests/qapi-schema/alternate-dict-invalid.json b/tests/qapi-schema/alternate-dict-invalid.json
new file mode 100644
index 0000000000..45f2c8ebef
--- /dev/null
+++ b/tests/qapi-schema/alternate-dict-invalid.json
@@ -0,0 +1,4 @@ 
+# invalid field dictionnary, missing type
+{ 'alternate': 'Alt',
+  'data': { 'one': 'str',
+            'two': { 'if': 'foo' } } }
diff --git a/tests/qapi-schema/alternate-dict-invalid.out b/tests/qapi-schema/alternate-dict-invalid.out
new file mode 100644
index 0000000000..e69de29bb2
diff --git a/tests/qapi-schema/qapi-schema-test.json b/tests/qapi-schema/qapi-schema-test.json
index 01f7db58dc..46a4d1c3e5 100644
--- a/tests/qapi-schema/qapi-schema-test.json
+++ b/tests/qapi-schema/qapi-schema-test.json
@@ -206,9 +206,13 @@ 
 { 'command': 'TestIfUnionCmd', 'data': { 'union_cmd_arg': 'TestIfUnion' },
   'if': 'defined(TEST_IF_UNION)' }
 
-{ 'alternate': 'TestIfAlternate', 'data': { 'foo': 'int', 'bar': 'TestStruct' },
+{ 'alternate': 'TestIfAlternate', 'data':
+  { 'foo': 'int', 'alt_bar': { 'type': 'TestStruct', 'if': 'defined(TEST_IF_ALT_BAR)'} },
   'if': 'defined(TEST_IF_ALT) && defined(TEST_IF_STRUCT)' }
 
+{ 'command': 'TestIfAlternateCmd', 'data': { 'alt_cmd_arg': 'TestIfAlternate' },
+  'if': 'defined(TEST_IF_ALT)' }
+
 { 'command': 'TestIfCmd', 'data':
   { 'foo': 'TestIfStruct', 'bar': { 'type': 'TestIfEnum', 'if': 'TEST_IF_CMD_BAR' } },
   'if': 'defined(TEST_IF_CMD) && defined(TEST_IF_STRUCT)' }
diff --git a/tests/qapi-schema/qapi-schema-test.out b/tests/qapi-schema/qapi-schema-test.out
index 7908eed6fc..a51c6ac15c 100644
--- a/tests/qapi-schema/qapi-schema-test.out
+++ b/tests/qapi-schema/qapi-schema-test.out
@@ -55,8 +55,11 @@  enum QType ['none', 'qnull', 'qnum', 'qstring', 'qdict', 'qlist', 'qbool']
 alternate TestIfAlternate
     tag type
     case foo: int
-    case bar: TestStruct
+    case alt_bar: TestStruct if=defined(TEST_IF_ALT_BAR)
     if defined(TEST_IF_ALT) && defined(TEST_IF_STRUCT)
+command TestIfAlternateCmd q_obj_TestIfAlternateCmd-arg -> None
+   gen=True success_response=True boxed=False
+    if defined(TEST_IF_ALT)
 command TestIfCmd q_obj_TestIfCmd-arg -> None
    gen=True success_response=True boxed=False
     if defined(TEST_IF_CMD) && defined(TEST_IF_STRUCT)
@@ -200,6 +203,9 @@  object q_obj_EVENT_D-arg
     member b: str optional=False
     member c: str optional=True
     member enum3: EnumOne optional=True
+object q_obj_TestIfAlternateCmd-arg
+    member alt_cmd_arg: TestIfAlternate optional=False
+    if defined(TEST_IF_ALT)
 object q_obj_TestIfCmd-arg
     member foo: TestIfStruct optional=False
     member bar: TestIfEnum optional=False if=TEST_IF_CMD_BAR