[SR-8490] objc readonly property overriden to readwrite in subclass incorrectly bridged as get-only (Swift 4.2 regression)

[bobergj]

Previous ID	SR-8490
Radar	rdar://problem/43057062
Original Reporter	@bobergj
Type	Bug
Status	Closed
Resolution	Done

Attachment: Download

Environment

Xcode 10.0 beta 5 (10L221o)

Additional Detail from JIRA

Votes	0
Component/s	Compiler
Labels	Bug, 4.2Regression, ClangImporter
Assignee	@belkadan
Priority	Medium

md5: 263f93699fc38d78453e79f78753428c

Issue Description:

Given a objc base class that has a readonly property and also conforms to ProtocolA:

@interface ClassA : NSObject <ProtocolA>
@property (readonly, nonatomic, nullable) NSString *aProperty;
@end

Where ProtocolA defines a getter for a property:

@protocol ProtocolA
- (nullable NSString *)aProperty;
@end

A subclass that redefines the property as readwrite:

@interface ClassB : ClassA
@property (readwrite, nonatomic, nullable) NSString *aProperty;
@end

The property is incorrectly bridged to readonly in Swift:

let classB = ClassB()
classB.aProperty = "foo" // Error: Cannot assign to property: 'aProperty' is a get-only property

This is a regression from Swift 4 / Xcode 9.4.1 (9F2000) where the property is bridged as readwrite.

Attached sample project that includes the code above.

[belkadan]

Thanks, Jonas!

@swift-ci create

[belkadan]

The protocol is relevant, too. I guess we're refusing to import the "conflicting" property before realizing that there's one in the superclass anyway.

[belkadan]

#18749

[bobergj]

@belkadan: I still see this issue in Xcode 10 GM - Version 10.0 (10A254a). Perhaps the commit was simply to late to be included in the release branch? But I am not sure which release branch to check.

[belkadan]

That's correct, the fix did not make it into the release branch. Sorry for the trouble.

[AnnaZaks]

@bobergj, Could you verify if the problem is fixed and if so move the JIRA to "Closed"?

Thanks!
Anna