fix(ffi): resolve protocol-only method metadata for block parameters - #71
Merged
Conversation
|
Important Review skippedAuto reviews are disabled on this repository. Please check the settings in the CodeRabbit UI or the ⚙️ Run configurationConfiguration used: Organization UI Review profile: CHILL Plan: Pro Plus Run ID: You can disable this status message by setting the Use the checkbox below for a quick retry:
Thanks for using CodeRabbit! It's free for OSS, and your support helps us grow. If you like it, consider giving us a shout-out. Comment |
This was referenced Aug 20, 2026
findClassForRuntimeClass only ever consulted the concrete class hierarchy (class_getSuperclass), so a selector declared solely on a conformed Objective-C protocol had no path to its metadata whenever the class that actually implements it doesn't carry that conformance in a header the metadata generator parsed -- a category/class-extension conformance, or (as with UIViewControllerTransitionCoordinator) a fully private concrete class. createEngineCallback then threw "Native callback metadata is unavailable." for any block parameter on such a method, forcing callers to hand-supply the ObjC encoding via interop.Block(fn, "..."). Adds a runtime protocol-conformance fallback (class_copyProtocolList + protocol_copyProtocolList, walked alongside the existing class walk), consulted only once the ordinary class/protocol-declared-on-header lookup misses, and cached per runtime Class so well-declared classes pay nothing extra. Deterministic tie-break for a class conforming to several protocols declaring the same selector: most-derived class first, then ancestors; within one class's own adopted-protocol list, class_copyProtocolList's order; each protocol's inherited protocols expanded depth-first ahead of its next sibling. First match wins. Covered by two new fixtures/tests mirroring the real-world shape (hidden vs. declared protocol conformance) plus the existing 717-test macOS suite (unchanged 8 pre-existing DBL_MAX failures, no new ones). Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01BQPGUU8YECUhbBvwkW4Kek
DjDeveloperr
force-pushed
the
ffi-protocol-method-metadata
branch
from
August 26, 2026 00:08
ce3d2a6 to
dcf739e
Compare
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
1 participant
Add this suggestion to a batch that can be applied as a single commit.This suggestion is invalid because no changes were made to the code.Suggestions cannot be applied while the pull request is closed.Suggestions cannot be applied while viewing a subset of changes.Only one suggestion per line can be applied in a batch.Add this suggestion to a batch that can be applied as a single commit.Applying suggestions on deleted lines is not supported.You must change the existing code in this line in order to create a valid suggestion.Outdated suggestions cannot be applied.This suggestion has been applied or marked resolved.Suggestions cannot be applied from pending reviews.Suggestions cannot be applied on multi-line comments.Suggestions cannot be applied while the pull request is queued to merge.Suggestion cannot be applied right now. Please check back later.
What was broken
If a method your app calls is declared only on an Objective-C protocol
(not on any real class in the object's chain), and takes a block
parameter, calling it from JS with a plain closure threw:
Error: Native callback metadata is unavailable.This happens whenever the class that actually implements the method
doesn't declare that conformance in a header the metadata generator
parsed -- e.g. conformance added via a category/class-extension, or a
fully private concrete class (
UIViewControllerTransitionCoordinatoris the classic real-world case: every method lives on the protocol,
the concrete class is private). The only workaround was hand-supplying
the ObjC encoding:
interop.Block(fn, "v@?@").Root cause:
findClassForRuntimeClass(ObjCBridge.mm) only walked theconcrete class hierarchy via
class_getSuperclass, never consultingprotocol conformance, so method lookup for such selectors came up
empty and the block parameter's metadata was never resolved.
The fix
Adds a protocol-conformance fallback (
class_copyProtocolList+protocol_copyProtocolList, walked alongside the existing class walk),consulted only once the ordinary class-hierarchy lookup misses, cached
per runtime
Classso classes with complete metadata pay nothingextra.
Duplicate-selector rule: most-derived class first, then ancestors;
within one class's own adopted-protocol list,
class_copyProtocolList'sorder (stable, reflects declaration order); each protocol's inherited
protocols expand depth-first before its next sibling. First match wins.
Verification
Two new fixtures (hidden vs. declared protocol conformance, same
selectors) prove the fix and that the already-working class path is
unaffected. Confirmed genuine repro: same tests fail with exactly this
error on the pre-fix code. Full macOS suite: 717 tests, 8 pre-existing
DBL_MAX-formatting failures (unchanged), 0 new failures.
Co-Authored-By: Claude Opus 5 (1M context) noreply@anthropic.com
https://claude.ai/code/session_01BQPGUU8YECUhbBvwkW4Kek