transitive dependency failed (oc ->(deps) swift ->(deps) oc/swift) about rules_apple

[lswith]

you should include the swift-Swift.h as well

[endpress]

@lswith my swift-Swift.h

#if defined(__has_feature) && __has_feature(modules)
@import ObjectiveC;
@import _oc;
#endif

#pragma clang diagnostic ignored "-Wproperty-attribute-mismatch"
#pragma clang diagnostic ignored "-Wduplicate-method-arg"

SWIFT_CLASS("_TtC5swift10SwiftClass")
@interface SwiftClass : NSObject <OCDelegate>
- (void)hello;
- (nonnull instancetype)init OBJC_DESIGNATED_INITIALIZER;
@end

#pragma clang diagnostic pop

[endpress]

@lswith @dmishe
I think it is a bug. swift library deps oc library. so the generated swift-Swift.h use @import _oc , but oc library cann't use @import syntax

[dmishe]

Nice catch. This is a side-effect of incomplete support for objc modules in Bazel. If you remove enable_modules attributes, and import oc headers directly in your objc source, the problem should be resolved.

[endpress]

@dmishe But my swift library used OCObject, the generated swift-Swift.h still has @import _oc,
how do I change my swift calss ? SwiftClass.swift

import UIKit
import _oc
public class SwiftClass: NSObject, OCDelegate { 
    var oc1: OCObject?
    public func hello() {        
    }
}

If I remove OCDelegate , the swift-Swift.h have no @import _oc,

import UIKit
import _oc
public class SwiftClass: NSObject { 
    var oc1: OCObject?
    public func hello() {        
    }
}

the swift-Swift.h is

#if defined(__has_feature) && __has_feature(modules)
@import ObjectiveC;
#endif

#pragma clang diagnostic ignored "-Wproperty-attribute-mismatch"
#pragma clang diagnostic ignored "-Wduplicate-method-arg"

SWIFT_CLASS("_TtC5swift10SwiftClass")
@interface SwiftClass : NSObject
- (void)hello;
- (nonnull instancetype)init OBJC_DESIGNATED_INITIALIZER;
@end

#pragma clang diagnostic pop

[dmishe]

You will be able to import objc_library as a module in Swift without enable_modules. We do some special things for swift_library targets that makes this possible.

[endpress]

If I add OCDelegate, it appears again

import UIKit
import _oc
public class SwiftClass: NSObject, OCDelegate { 
    var oc1: OCObject?
    public func hello() {        
    }
}

the swift-Swift.h

#if defined(__has_feature) && __has_feature(modules)
@import ObjectiveC;
@import _oc;
#endif

#pragma clang diagnostic ignored "-Wproperty-attribute-mismatch"
#pragma clang diagnostic ignored "-Wduplicate-method-arg"

SWIFT_CLASS("_TtC5swift10SwiftClass")
@interface SwiftClass : NSObject <OCDelegate>
- (void)hello;
- (nonnull instancetype)init OBJC_DESIGNATED_INITIALIZER;
@end

#pragma clang diagnostic pop

Because OCDelegate is decleared in _oc, so @import _oc is added in swift-Swift.h

[dmishe]

Yep and that's fine. The important thing is that without enable_modules=1 on the Objective-C side, those imports will never be hit (since __has_feature(modules) will return false).

The downside, as a mentioned above, is that you will need to import oc headers before the swift header every time you use it.

[endpress]

@dmishe really really thank you.

[dmishe]

No problem.