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Swift importer generates unusable signature for resumeExternalUserAgentFlow(with:error:) #964
Description
Describe the bug
After the addition of resumeExternalUserAgentFlowWithURL:error: in PR #955, the new API appears to be imported incorrectly into Swift.
The Objective-C declaration is:
- (BOOL)resumeExternalUserAgentFlowWithURL:(NSURL *)URL
error:(NSError *_Nullable *_Nullable)error;
However, Swift resolves the method as if the second parameter has type (), resulting in autocomplete like:
flow.resumeExternalUserAgentFlow?(with: url, error: ())
Passing nil or an NSError pointer is not possible, producing errors such as:
'nil' is not compatible with expected argument type '()'
As a result, the new API is effectively unusable from Swift, while the deprecated overload still works.
Screenshots
Environment
- AppAuth 2.1.0
- Xcode 26.6
- iOS 26.5
Suggested fix
Any of:
Make resumeExternalUserAgentFlowWithURL:error: @required (major bump if needed), or
Keep @optional for ObjC but add a Swift overlay / NS_SWIFT_NAME so the documented throwing API is real, or
Update README + Swift examples to stop showing try …(with:) until Swift can call the new method, and document the ObjC-only / wrapper path
Happy to help test a patch.
Activity
w-goog commentedon Jul 21, 2026
Thank you so much for the report, Oleksandr! I've put up a PR to fix & we'll release it as a patch :)
mbernson commentedon Jul 22, 2026
Hi, I ran into the same issue, hence I was taking a look here. The fix in #966 looks good but there's one more thing I'd like to request.
The new delegate method
-[OIDExternalUserAgentSession resumeExternalUserAgentFlowWithURL:error:]is marked as@optional, but I would argue that it should be a required method.Having it be optional indicates to me that a certain User Agent Session may or may not implement it. This is not true, as it is the only replacement for the deprecated
-[OIDExternalUserAgentSession resumeExternalUserAgentFlowWithURL:]method. Also, resuming the session after authentication is the happy path that should always be possible. An certain Session class should not be able to skip its implementation.The call site also becomes a little bit awkward in Swift with the question mark and having to unwrap the result boolean.
Making the new method required does break source compatibility and therefore a major version bump must be done according to SemVer. This was probably your reason to make it optional in the first place. But I think a major version bump is the better option here.
w-goog commentedon Jul 22, 2026
"This was probably your reason to make it optional in the first place. But I think a major version bump is the better option here."
Indeed, that is the reason - to give our clients time to migrate :) In the next major release, we'll change the deprecation to no longer be a warning, and make the optional method required.