@@ -635,25 +635,39 @@ def __init__(self, tag_name, info, tag_member, variants):
assert isinstance(v, QAPISchemaVariant)
self._tag_name = tag_name
self.info = info
- self.tag_member = tag_member
+ self._tag_member: Optional[QAPISchemaObjectTypeMember] = tag_member
self.variants = variants
+ @property
+ def tag_member(self) -> 'QAPISchemaObjectTypeMember':
+ if self._tag_member is None:
+ raise RuntimeError(
+ "QAPISchemaVariants has no tag_member property until "
+ "after check() has been run."
+ )
+ return self._tag_member
+
def set_defined_in(self, name):
for v in self.variants:
v.set_defined_in(name)
def check(self, schema, seen):
if self._tag_name: # union
- self.tag_member = seen.get(c_name(self._tag_name))
+ # We need to narrow the member type:
+ tmp = seen.get(c_name(self._tag_name))
+ assert tmp is None or isinstance(tmp, QAPISchemaObjectTypeMember)
+ self._tag_member = tmp
+
base = "'base'"
# Pointing to the base type when not implicit would be
# nice, but we don't know it here
- if not self.tag_member or self._tag_name != self.tag_member.name:
+ if not self._tag_member or self._tag_name != self._tag_member.name:
raise QAPISemError(
self.info,
"discriminator '%s' is not a member of %s"
% (self._tag_name, base))
# Here we do:
+ assert self.tag_member.defined_in
base_type = schema.resolve_type(self.tag_member.defined_in)
if not base_type.is_implicit():
base = "base type '%s'" % self.tag_member.defined_in
@@ -673,11 +687,13 @@ def check(self, schema, seen):
"discriminator member '%s' of %s must not be conditional"
% (self._tag_name, base))
else: # alternate
+ assert self._tag_member
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: # union
# branches that are not explicitly covered get an empty type
+ assert self.tag_member.defined_in
cases = {v.name for v in self.variants}
for m in self.tag_member.type.members:
if m.name not in cases:
There are two related changes here: (1) We need to perform type narrowing for resolving the type of tag_member during check(), and (2) tag_member is a delayed initialization field, but we can hide it behind a property that raises an Exception if it's called too early. This simplifies the typing in quite a few places and avoids needing to assert that the "tag_member is not None" at a dozen callsites, which can be confusing and suggest the wrong thing to a drive-by contributor. Signed-off-by: John Snow <jsnow@redhat.com> --- scripts/qapi/schema.py | 22 +++++++++++++++++++--- 1 file changed, 19 insertions(+), 3 deletions(-)