Eric Blake <ebl...@redhat.com> writes: > On 9/14/19 10:35 AM, Markus Armbruster wrote: >> Entity checking goes back to commit ac88219a6c "qapi: New QAPISchema >> intermediate representation", v2.5.0. It's designed to work as >> follows: QAPISchema.check() calls .check() for all the schema's >> entities. An entity's .check() recurses into another entity's >> .check() only if the C struct generated for the former contains the C >> struct generated for the latter (pointers don't count). This is used >> to detect "object contains itself". >> >> There are two instances of this: >> >> * An object's C struct contains its base's C struct >> >> QAPISchemaObjectType.check() calls self.base.check() >> >> * An object's C struct contains its variants' C structs >> >> QAPISchemaObjectTypeVariants().check calls v.type.check(). Since >> commit b807a1e1e3 "qapi: Check for QAPI collisions involving variant >> members", v2.6.0. >> > >> Sadly, this design has since eroded: >> > >> * A QAPISchemaEntity's .module becomes valid at .check(). This is >> because computing it needs info and schema.fname, and because array >> types get it from their element type instead. >> >> Make it a property just like .ifcond. > > Extra space.
Will fix. >> Additionally, have QAPISchemaEntity.check() assert it gets called at >> most once, so the design invariant will stick this time. Neglecting >> that was entirely my fault. > > Lengthy explanation, but it makes sense. Writing the commit message was more work than writing the patch... >> >> Signed-off-by: Markus Armbruster <arm...@redhat.com> >> --- >> scripts/qapi/common.py | 74 +++++++++++++++++++++++++++++------------- >> 1 file changed, 52 insertions(+), 22 deletions(-) >> > > Took me a bit longer to read this (and refresh myself on what > '@property' actually does in Python, but you're not the first user of it > in qemu), but it matches the commit message. > > Reviewed-by: Eric Blake <ebl...@redhat.com> Thanks!
