Kotlin-native: Conflicting nullability in StdlibComparable and StdlibEnum in Objective-C

[ghost]

Xcode shows a warning from the iOS framework header when using enums in Kotlin. This resulting framework header has conflicting nullabillity on compareToOther::

@protocol StdlibComparable
@required
- (int32_t)compareToOther:(id _Nullable)other __attribute__((swift_name("compareTo(other:)")));
@end;

@interface StdlibEnum : KotlinBase <StdlibComparable>
- (instancetype)initWithName:(NSString *)name ordinal:(int32_t)ordinal __attribute__((swift_name("init(name:ordinal:)"))) __attribute__((objc_designated_initializer));
- (id)clone __attribute__((swift_name("clone()")));
- (int32_t)compareToOther:(StdlibEnum *)other __attribute__((swift_name("compareTo(other:)")));
@property (readonly) NSString *name;
@property (readonly) int32_t ordinal;
@end;

This is the warning from Xcode:
Conflicting nullability specifier on parameter types, 'nonnull' conflicts with existing specifier '_Nullable'

As you can see the StdlibComparable has the _Nullable keyword, but the implementation of StdlibEnum does not have the _Nullable keyword.

[olonho]

Does it produce any real issues beyond a warning?

[ghost]

No it does not, but a framework shouldn't contain any warnings. It isn't exactly a quality mark that the first thing you see is a warning :)

[NilsLattek]

We are also running into this issue and we now have this warning over 80 times in our project.
This makes it hard to see other warnings in the project.

[SvyatoslavScherbina]

To workaround the issue add -Xcc -Wno-nullability to "Other Swift Flags" in "Build Settings".

(If you import Kotlin framework to Objective-C code, then also add -Wno-nullability to "Other C Flags).

[DTHeaven]

To workaround the issue add -Xcc -Wno-nullability to "Other Swift Flags" in "Build Settings".

(If you import Kotlin framework to Objective-C code, then also add -Wno-nullability to "Other C Flags).

Why not to fix it?

[NilsLattek]

To workaround the issue add -Xcc -Wno-nullability to "Other Swift Flags" in "Build Settings".

(If you import Kotlin framework to Objective-C code, then also add -Wno-nullability to "Other C Flags).

Thanks, that helps until it is resolved in Kotlin native.

[SvyatoslavScherbina]

Fixed in 1.3.41 and 1.3.50.