Dario Gabriel LipicarandClaude Opus 5 f03a5d8bf6 fix(ext): the two providers agree on echoOptional again, at -> ?tstr ...

One contract had two providers answering different SHAPES.
test_fullapi_ext_rust.lidl declared `echoOptional(v: ?tstr) -> result`;
test_fullapi_ext_cpp is header-first and kept deriving `-> ?tstr` from
`std::optional<std::string> echoOptional(...)`. Carried as known-ext.json's
`ext-optional-return-changed-on-one-provider`, and visible on a second surface
as `ext-optional-return-shape-through-the-qt-proxy`.

THE WORKAROUND OUTLIVED ITS CAUSE. `-> result` was chosen because
`logos-qt-generator --backend consumer` REFUSED `-> ?T` -- null was also how a
failed call reported itself on that path, so an empty ?T and a failure were one
wire value. That gate is retired: `lidlTypeToQt` maps `?T` to
std::optional<T>, so the empty answer is std::nullopt, an inhabitant of its
own, and failure travels on logos::CallError, decided by the C ABI return code
and never by the value's null-ness.

So `-> ?tstr` is emittable today, it is what the C++ provider already derives,
and it is what the case table already expects. Reverting the Rust side is what
makes the two agree; the alternative (moving C++ to `-> result`) would have
meant changing the expectations to match a workaround for a constraint that no
longer exists.

Changed together, because a proxy that forwards a shape must declare the same
one: the Rust LIDL and its impl (`Option<String>` in and out, no success flag
standing in for presence), the qtproxy's own interfaces/full_api_ext.lidl, and
the qtproxy impl's echoOptional -- which now forwards through sOptStr rather
than sResult, and renders with rOpt rather than rResult in the exercise-all and
async blocks.

Both registry entries are retired. The proxy one had a SECOND, independent half
-- a Qt wrapper that could not decode a reply returned a default-constructed
LogosResult, and that default is byte-for-byte a provider refusal -- which is
fixed in logos-qt-sdk#44 and logos-cpp-sdk#150 and stands whichever shape the
contract had chosen. Recorded in the `fixed` entry, because retiring it here
without naming that half would credit the shape change with more than it did.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

2026-08-24 14:33:47 -03:00

..

full_api_ext.lidl

fix(ext): the two providers agree on echoOptional again, at -> ?tstr

2026-08-24 14:33:47 -03:00