qapi: add QAPISchemaIfCond.is_present()

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20210804083105.97531-4-marcandre.lureau@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>

4 files changed, 12 insertions, 9 deletions

diff --git a/docs/sphinx/qapidoc.py b/docs/sphinx/qapidoc.py
index 0eac3308b2..511520f33f 100644
--- a/docs/sphinx/qapidoc.py
+++ b/docs/sphinx/qapidoc.py
@@ -139,7 +139,7 @@ class QAPISchemaGenRSTVisitor(QAPISchemaVisitor):
             term.append(nodes.literal('', member.type.doc_type()))
         if member.optional:
             term.append(nodes.Text(' (optional)'))
-        if member.ifcond.ifcond:
+        if member.ifcond.is_present():
             term.extend(self._nodes_for_ifcond(member.ifcond))
         return term
 
@@ -154,7 +154,7 @@ class QAPISchemaGenRSTVisitor(QAPISchemaVisitor):
                 nodes.literal('', variants.tag_member.name),
                 nodes.Text(' is '),
                 nodes.literal('', '"%s"' % variant.name)]
-        if variant.ifcond.ifcond:
+        if variant.ifcond.is_present():
             term.extend(self._nodes_for_ifcond(variant.ifcond))
         return term
 
@@ -209,7 +209,7 @@ class QAPISchemaGenRSTVisitor(QAPISchemaVisitor):
         dlnode = nodes.definition_list()
         for section in doc.args.values():
             termtext = [nodes.literal('', section.member.name)]
-            if section.member.ifcond.ifcond:
+            if section.member.ifcond.is_present():
                 termtext.extend(self._nodes_for_ifcond(section.member.ifcond))
             # TODO drop fallbacks when undocumented members are outlawed
             if section.text:
@@ -277,7 +277,7 @@ class QAPISchemaGenRSTVisitor(QAPISchemaVisitor):
     def _nodes_for_if_section(self, ifcond):
         """Return list of doctree nodes for the "If" section"""
         nodelist = []
-        if ifcond.ifcond:
+        if ifcond.is_present():
             snode = self._make_section('If')
             snode += nodes.paragraph(
                 '', '', *self._nodes_for_ifcond(ifcond, with_if=False)
diff --git a/scripts/qapi/introspect.py b/scripts/qapi/introspect.py
index db1ebbf53a..e23725e2f9 100644
--- a/scripts/qapi/introspect.py
+++ b/scripts/qapi/introspect.py
@@ -123,10 +123,10 @@ def _tree_to_qlit(obj: JSONValue,
         ret = ''
         if obj.comment:
             ret += indent(level) + f"/* {obj.comment} */\n"
-        if obj.ifcond.ifcond:
+        if obj.ifcond.is_present():
             ret += gen_if(obj.ifcond.ifcond)
         ret += _tree_to_qlit(obj.value, level)
-        if obj.ifcond.ifcond:
+        if obj.ifcond.is_present():
             ret += '\n' + gen_endif(obj.ifcond.ifcond)
         return ret
 
diff --git a/scripts/qapi/schema.py b/scripts/qapi/schema.py
index e3beb24500..86fcd6cbd5 100644
--- a/scripts/qapi/schema.py
+++ b/scripts/qapi/schema.py
@@ -29,6 +29,9 @@ class QAPISchemaIfCond:
     def __init__(self, ifcond=None):
         self.ifcond = ifcond or []
 
+    def is_present(self):
+        return bool(self.ifcond)
+
 
 class QAPISchemaEntity:
     meta: Optional[str] = None
@@ -598,7 +601,7 @@ class QAPISchemaVariants:
                     self.info,
                     "discriminator member '%s' of %s must not be optional"
                     % (self._tag_name, base))
-            if self.tag_member.ifcond.ifcond:
+            if self.tag_member.ifcond.is_present():
                 raise QAPISemError(
                     self.info,
                     "discriminator member '%s' of %s must not be conditional"
@@ -606,7 +609,7 @@ class QAPISchemaVariants:
         else:                   # simple union
             assert isinstance(self.tag_member.type, QAPISchemaEnumType)
             assert not self.tag_member.optional
-            assert self.tag_member.ifcond.ifcond == []
+            assert not self.tag_member.ifcond.is_present()
         if self._tag_name:    # flat union
             # branches that are not explicitly covered get an empty type
             cases = {v.name for v in self.variants}
diff --git a/tests/qapi-schema/test-qapi.py b/tests/qapi-schema/test-qapi.py
index 7907b4ac3a..c92be2d086 100755
--- a/tests/qapi-schema/test-qapi.py
+++ b/tests/qapi-schema/test-qapi.py
@@ -94,7 +94,7 @@ class QAPISchemaTestVisitor(QAPISchemaVisitor):
 
     @staticmethod
     def _print_if(ifcond, indent=4):
-        if ifcond.ifcond:
+        if ifcond.is_present():
             print('%sif %s' % (' ' * indent, ifcond.ifcond))
 
     @classmethod