[PATCH 37/42] qapi/schema: add __iter__ method to QAPISchemaVariants

[John Snow <jsnow@redhat.com>]

This is just semantic sugar that makes it easier to do something like:

for var in variants:
    ...

Instead of the more cumbersome and repetitive:

for var in variants.variants:
    ...

Especially in conjunction with entities that aren't guaranteed to have
variants. Compare:

for var in variants.variants if variants else []:
    ...

against:

for var in variants or []:
    ...

Update callsites to reflect the new usage pattern.

Signed-off-by: John Snow <jsnow@redhat.com>
---
 docs/sphinx/qapidoc.py     | 2 +-
 scripts/qapi/introspect.py | 4 ++--
 scripts/qapi/schema.py     | 8 ++++++--
 scripts/qapi/types.py      | 4 ++--
 scripts/qapi/visit.py      | 4 ++--
 5 files changed, 13 insertions(+), 9 deletions(-)

diff --git a/docs/sphinx/qapidoc.py b/docs/sphinx/qapidoc.py
index 81133b9b441..755eb0fa0ec 100644
--- a/docs/sphinx/qapidoc.py
+++ b/docs/sphinx/qapidoc.py
@@ -695,7 +695,7 @@ def _nodes_for_members(self, doc, what, base=None, branches=None):
                                         None)
 
         if branches:
-            for v in branches.variants:
+            for v in branches:
                 if v.type.name == 'q_empty':
                     continue
                 assert not v.type.is_implicit()
diff --git a/scripts/qapi/introspect.py b/scripts/qapi/introspect.py
index ac14b20f308..6ec34e055d3 100644
--- a/scripts/qapi/introspect.py
+++ b/scripts/qapi/introspect.py
@@ -342,7 +342,7 @@ def visit_object_type_flat(self, name: str, info: Optional[QAPISourceInfo],
         }
         if branches:
             obj['tag'] = branches.tag_member.name
-            obj['variants'] = [self._gen_variant(v) for v in branches.variants]
+            obj['variants'] = [self._gen_variant(v) for v in branches]
         self._gen_tree(name, 'object', obj, ifcond, features)
 
     def visit_alternate_type(self, name: str, info: Optional[QAPISourceInfo],
@@ -353,7 +353,7 @@ def visit_alternate_type(self, name: str, info: Optional[QAPISourceInfo],
             name, 'alternate',
             {'members': [Annotated({'type': self._use_type(m.type)},
                                    m.ifcond)
-                         for m in alternatives.variants]},
+                         for m in alternatives]},
             ifcond, features
         )
 
diff --git a/scripts/qapi/schema.py b/scripts/qapi/schema.py
index e97c978d38d..4c55f7640b6 100644
--- a/scripts/qapi/schema.py
+++ b/scripts/qapi/schema.py
@@ -26,6 +26,7 @@
     Any,
     Callable,
     Dict,
+    Iterator,
     List,
     Optional,
     Union,
@@ -669,7 +670,7 @@ def check(self, schema: QAPISchema) -> None:
         # so we have to check for potential name collisions ourselves.
         seen: Dict[str, QAPISchemaMember] = {}
         types_seen: Dict[str, str] = {}
-        for v in self.alternatives.variants:
+        for v in self.alternatives:
             v.check_clash(self.info, seen)
             qtype = v.type.alternate_qtype()
             if not qtype:
@@ -700,7 +701,7 @@ def check(self, schema: QAPISchema) -> None:
     def connect_doc(self, doc: Optional[QAPIDoc] = None) -> None:
         super().connect_doc(doc)
         doc = doc or self.doc
-        for v in self.alternatives.variants:
+        for v in self.alternatives:
             v.connect_doc(doc)
 
     def c_type(self) -> str:
@@ -726,6 +727,9 @@ def __init__(
         self.tag_member: QAPISchemaObjectTypeMember
         self.variants = variants
 
+    def __iter__(self) -> Iterator[QAPISchemaVariant]:
+        return iter(self.variants)
+
     def set_defined_in(self, name: str) -> None:
         for v in self.variants:
             v.set_defined_in(name)
diff --git a/scripts/qapi/types.py b/scripts/qapi/types.py
index 0dd0b00ada3..ad36b55488f 100644
--- a/scripts/qapi/types.py
+++ b/scripts/qapi/types.py
@@ -166,7 +166,7 @@ def gen_object(name: str, ifcond: QAPISchemaIfCond,
     objects_seen.add(name)
 
     ret = ''
-    for var in variants.variants if variants else ():
+    for var in variants or ():
         obj = var.type
         if not isinstance(obj, QAPISchemaObjectType):
             continue
@@ -234,7 +234,7 @@ def gen_variants(variants: QAPISchemaVariants) -> str:
 ''',
                 c_name=c_name(variants.tag_member.name))
 
-    for var in variants.variants:
+    for var in variants:
         if var.type.name == 'q_empty':
             continue
         ret += var.ifcond.gen_if()
diff --git a/scripts/qapi/visit.py b/scripts/qapi/visit.py
index 12f92e429f6..1eca452378c 100644
--- a/scripts/qapi/visit.py
+++ b/scripts/qapi/visit.py
@@ -141,7 +141,7 @@ def gen_visit_object_members(name: str,
 ''',
                      c_name=c_name(tag_member.name))
 
-        for var in branches.variants:
+        for var in branches:
             case_str = c_enum_const(tag_member.type.name, var.name,
                                     tag_member.type.prefix)
             ret += var.ifcond.gen_if()
@@ -246,7 +246,7 @@ def gen_visit_alternate(name: str,
 ''',
                 c_name=c_name(name))
 
-    for var in alternatives.variants:
+    for var in alternatives:
         ret += var.ifcond.gen_if()
         ret += mcgen('''
     case %(case)s:
-- 
2.48.1