Merge remote-tracking branch 'remotes/armbru/tags/pull-qapi-2021-09-25-v2' into staging

QAPI patches patches for 2021-09-25

# gpg: Signature made Mon 27 Sep 2021 13:44:23 BST
# gpg:                using RSA key 354BC8B3D7EB2A6B68674E5F3870B400EB918653
# gpg:                issuer "armbru@redhat.com"
# gpg: Good signature from "Markus Armbruster <armbru@redhat.com>" [full]
# gpg:                 aka "Markus Armbruster <armbru@pond.sub.org>" [full]
# Primary key fingerprint: 354B C8B3 D7EB 2A6B 6867  4E5F 3870 B400 EB91 8653

* remotes/armbru/tags/pull-qapi-2021-09-25-v2: (25 commits)
  tests/qapi-schema: Make test-qapi.py -u work when files are absent
  tests/qapi-schema: Use Python OSError instead of outmoded IOError
  test-clone-visitor: Correct an accidental rename
  tests/qapi-schema: Rename flat-union-* test cases to union-*
  qapi: Drop simple unions
  tests/qapi-schema: Purge simple unions from tests
  tests/qapi-schema: Drop simple union __org.qemu_x-Union1
  test-clone-visitor: Wean off __org.qemu_x-Union1
  tests/qapi-schema: Rewrite simple union TestIfUnion to be flat
  tests/qapi-schema: Simple union UserDefListUnion is now unused, drop
  tests/qapi-schema: Wean off UserDefListUnion
  test-clone-visitor: Wean off UserDefListUnion
  test-qobject-output-visitor: Wean off UserDefListUnion
  test-qobject-input-visitor: Wean off UserDefListUnion
  tests/qapi-schema: Prepare for simple union UserDefListUnion removal
  qapi: Convert simple union TransactionAction to flat one
  qapi: Convert simple union ImageInfoSpecific to flat one
  qapi: Convert simple union SocketAddressLegacy to flat one
  qapi: Convert simple union ChardevBackend to flat one
  qapi: Convert simple union MemoryDeviceInfo to flat one
  ...

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

2 files changed, 31 insertions, 97 deletions

diff --git a/scripts/qapi/expr.py b/scripts/qapi/expr.py
index 90bde501b0..819ea6ad97 100644
--- a/scripts/qapi/expr.py
+++ b/scripts/qapi/expr.py
@@ -171,7 +171,7 @@ def check_defn_name_str(name: str, info: QAPISourceInfo, meta: str) -> None:
       - 'event' names adhere to `check_name_upper()`.
       - 'command' names adhere to `check_name_lower()`.
       - Else, meta is a type, and must pass `check_name_camel()`.
-        These names must not end with ``Kind`` nor ``List``.
+        These names must not end with ``List``.
 
     :param name: Name to check.
     :param info: QAPI schema source file information.
@@ -187,9 +187,9 @@ def check_defn_name_str(name: str, info: QAPISourceInfo, meta: str) -> None:
             permit_underscore=name in info.pragma.command_name_exceptions)
     else:
         check_name_camel(name, info, meta)
-        if name.endswith('Kind') or name.endswith('List'):
+        if name.endswith('List'):
             raise QAPISemError(
-                info, "%s name should not end in '%s'" % (meta, name[-4:]))
+                info, "%s name should not end in 'List'" % meta)
 
 
 def check_keys(value: _JSONObject,
@@ -513,27 +513,18 @@ def check_union(expr: _JSONObject, info: QAPISourceInfo) -> None:
     :return: None, ``expr`` is normalized in-place as needed.
     """
     name = cast(str, expr['union'])  # Checked in check_exprs
-    base = expr.get('base')
-    discriminator = expr.get('discriminator')
+    base = expr['base']
+    discriminator = expr['discriminator']
     members = expr['data']
 
-    if discriminator is None:   # simple union
-        if base is not None:
-            raise QAPISemError(info, "'base' requires 'discriminator'")
-    else:                       # flat union
-        check_type(base, info, "'base'", allow_dict=name)
-        if not base:
-            raise QAPISemError(info, "'discriminator' requires 'base'")
-        check_name_is_str(discriminator, info, "'discriminator'")
+    check_type(base, info, "'base'", allow_dict=name)
+    check_name_is_str(discriminator, info, "'discriminator'")
 
     if not isinstance(members, dict):
         raise QAPISemError(info, "'data' must be an object")
 
     for (key, value) in members.items():
         source = "'data' member '%s'" % key
-        if discriminator is None:
-            check_name_lower(key, info, source)
-        # else: name is in discriminator enum, which gets checked
         check_keys(value, info, source, ['type'], ['if'])
         check_if(value, info, source)
         check_type(value['type'], info, source, allow_array=not base)
@@ -664,8 +655,8 @@ def check_exprs(exprs: List[_JSONObject]) -> List[_JSONObject]:
             check_enum(expr, info)
         elif meta == 'union':
             check_keys(expr, info, meta,
-                       ['union', 'data'],
-                       ['base', 'discriminator', 'if', 'features'])
+                       ['union', 'base', 'discriminator', 'data'],
+                       ['if', 'features'])
             normalize_members(expr.get('base'))
             normalize_members(expr['data'])
             check_union(expr, info)
diff --git a/scripts/qapi/schema.py b/scripts/qapi/schema.py
index 3d72c7dfc9..004d7095ff 100644
--- a/scripts/qapi/schema.py
+++ b/scripts/qapi/schema.py
@@ -321,8 +321,8 @@ class QAPISchemaEnumType(QAPISchemaType):
             m.connect_doc(doc)
 
     def is_implicit(self):
-        # See QAPISchema._make_implicit_enum_type() and ._def_predefineds()
-        return self.name.endswith('Kind') or self.name == 'QType'
+        # See QAPISchema._def_predefineds()
+        return self.name == 'QType'
 
     def c_type(self):
         return c_name(self.name)
@@ -393,8 +393,7 @@ class QAPISchemaObjectType(QAPISchemaType):
     def __init__(self, name, info, doc, ifcond, features,
                  base, local_members, variants):
         # struct has local_members, optional base, and no variants
-        # flat union has base, variants, and no local_members
-        # simple union has local_members, variants, and no base
+        # union has base, variants, and no local_members
         super().__init__(name, info, doc, ifcond, features)
         self.meta = 'union' if variants else 'struct'
         assert base is None or isinstance(base, str)
@@ -465,15 +464,6 @@ class QAPISchemaObjectType(QAPISchemaType):
         for m in self.local_members:
             m.connect_doc(doc)
 
-    @property
-    def ifcond(self):
-        assert self._checked
-        if isinstance(self._ifcond, QAPISchemaType):
-            # Simple union wrapper type inherits from wrapped type;
-            # see _make_implicit_object_type()
-            return self._ifcond.ifcond
-        return self._ifcond
-
     def is_implicit(self):
         # See QAPISchema._make_implicit_object_type(), as well as
         # _def_predefineds()
@@ -576,10 +566,9 @@ class QAPISchemaAlternateType(QAPISchemaType):
 
 class QAPISchemaVariants:
     def __init__(self, tag_name, info, tag_member, variants):
-        # Flat unions pass tag_name but not tag_member.
-        # Simple unions and alternates pass tag_member but not tag_name.
-        # After check(), tag_member is always set, and tag_name remains
-        # a reliable witness of being used by a flat union.
+        # Unions pass tag_name but not tag_member.
+        # Alternates pass tag_member but not tag_name.
+        # After check(), tag_member is always set.
         assert bool(tag_member) != bool(tag_name)
         assert (isinstance(tag_name, str) or
                 isinstance(tag_member, QAPISchemaObjectTypeMember))
@@ -595,7 +584,7 @@ class QAPISchemaVariants:
             v.set_defined_in(name)
 
     def check(self, schema, seen):
-        if not self.tag_member:  # flat union
+        if self._tag_name:      # union
             self.tag_member = seen.get(c_name(self._tag_name))
             base = "'base'"
             # Pointing to the base type when not implicit would be
@@ -625,11 +614,11 @@ class QAPISchemaVariants:
                     self.info,
                     "discriminator member '%s' of %s must not be conditional"
                     % (self._tag_name, base))
-        else:                   # simple union
+        else:                   # alternate
             assert isinstance(self.tag_member.type, QAPISchemaEnumType)
             assert not self.tag_member.optional
             assert not self.tag_member.ifcond.is_present()
-        if self._tag_name:    # flat union
+        if self._tag_name:      # union
             # branches that are not explicitly covered get an empty type
             cases = {v.name for v in self.variants}
             for m in self.tag_member.type.members:
@@ -707,18 +696,10 @@ class QAPISchemaMember:
                 assert role == 'member'
                 role = 'parameter'
             elif defined_in.endswith('-base'):
-                # Implicit type created for a flat union's dict 'base'
+                # Implicit type created for a union's dict 'base'
                 role = 'base ' + role
             else:
-                # Implicit type created for a simple union's branch
-                assert defined_in.endswith('-wrapper')
-                # Unreachable and not implemented
                 assert False
-        elif defined_in.endswith('Kind'):
-            # See QAPISchema._make_implicit_enum_type()
-            # Implicit enum created for simple union's branches
-            assert role == 'value'
-            role = 'branch'
         elif defined_in != info.defn_name:
             return "%s '%s' of type '%s'" % (role, self.name, defined_in)
         return "%s '%s'" % (role, self.name)
@@ -1004,15 +985,6 @@ class QAPISchema:
                                      QAPISchemaIfCond(v.get('if')))
                 for v in values]
 
-    def _make_implicit_enum_type(self, name, info, ifcond, values):
-        # See also QAPISchemaObjectTypeMember.describe()
-        name = name + 'Kind'    # reserved by check_defn_name_str()
-        self._def_entity(QAPISchemaEnumType(
-            name, info, None, ifcond, None,
-            self._make_enum_members(values, info),
-            None))
-        return name
-
     def _make_array_type(self, element_type, info):
         name = element_type + 'List'    # reserved by check_defn_name_str()
         if not self.lookup_type(name):
@@ -1026,17 +998,9 @@ class QAPISchema:
         name = 'q_obj_%s-%s' % (name, role)
         typ = self.lookup_entity(name, QAPISchemaObjectType)
         if typ:
-            # The implicit object type has multiple users.  This is
-            # either a duplicate definition (which will be flagged
-            # later), or an implicit wrapper type used for multiple
-            # simple unions.  In the latter case, ifcond should be the
-            # disjunction of its user's ifconds.  Not implemented.
-            # Instead, we always pass the wrapped type's ifcond, which
-            # is trivially the same for all users.  It's also
-            # necessary for the wrapper to compile.  But it's not
-            # tight: the disjunction need not imply it.  We may end up
-            # compiling useless wrapper types.
-            # TODO kill simple unions or implement the disjunction
+            # The implicit object type has multiple users.  This can
+            # only be a duplicate definition, which will be flagged
+            # later.
             pass
         else:
             self._def_entity(QAPISchemaObjectType(
@@ -1084,49 +1048,28 @@ class QAPISchema:
     def _make_variant(self, case, typ, ifcond, info):
         return QAPISchemaVariant(case, info, typ, ifcond)
 
-    def _make_simple_variant(self, case, typ, ifcond, info):
-        if isinstance(typ, list):
-            assert len(typ) == 1
-            typ = self._make_array_type(typ[0], info)
-        typ = self._make_implicit_object_type(
-            typ, info, self.lookup_type(typ),
-            'wrapper', [self._make_member('data', typ, None, None, info)])
-        return QAPISchemaVariant(case, info, typ, ifcond)
-
     def _def_union_type(self, expr, info, doc):
         name = expr['union']
+        base = expr['base']
+        tag_name = expr['discriminator']
         data = expr['data']
-        base = expr.get('base')
         ifcond = QAPISchemaIfCond(expr.get('if'))
         features = self._make_features(expr.get('features'), info)
-        tag_name = expr.get('discriminator')
-        tag_member = None
         if isinstance(base, dict):
             base = self._make_implicit_object_type(
                 name, info, ifcond,
                 'base', self._make_members(base, info))
-        if tag_name:
-            variants = [
-                self._make_variant(key, value['type'],
-                                   QAPISchemaIfCond(value.get('if')),
-                                   info)
-                for (key, value) in data.items()]
-            members = []
-        else:
-            variants = [
-                self._make_simple_variant(key, value['type'],
-                                          QAPISchemaIfCond(value.get('if')),
-                                          info)
-                for (key, value) in data.items()]
-            enum = [{'name': v.name, 'if': v.ifcond.ifcond} for v in variants]
-            typ = self._make_implicit_enum_type(name, info, ifcond, enum)
-            tag_member = QAPISchemaObjectTypeMember('type', info, typ, False)
-            members = [tag_member]
+        variants = [
+            self._make_variant(key, value['type'],
+                               QAPISchemaIfCond(value.get('if')),
+                               info)
+            for (key, value) in data.items()]
+        members = []
         self._def_entity(
             QAPISchemaObjectType(name, info, doc, ifcond, features,
                                  base, members,
                                  QAPISchemaVariants(
-                                     tag_name, info, tag_member, variants)))
+                                     tag_name, info, None, variants)))
 
     def _def_alternate_type(self, expr, info, doc):
         name = expr['alternate']