macOS: Fix selector response checking for undocumented cursors #4033
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`AnyClass::responds_to` delegates to `class_respondsToSelector`, a function provided by the Objective-C runtime. However, at some point, this began to return `false` for selectors referring to undocumented cursors, despite the cursors remaining accessible via said selectors. That this check fails prevents the cursors from being used. We can instead send `respondsToSelector:` to the `NSCursor` class itself. As an instance method, this is nominally impossible; however, Apple grants an exemption[1] that permits class objects to perform instance methods defined in the root class. [1]: https://developer.apple.com/library/archive/documentation/Cocoa/Conceptual/ObjectiveC/Chapters/ocObjectsClasses.html#//apple_ref/doc/uid/TP30001163-CH11-TPXREF120 Checking for the undocumented cursors in this way gets them working again, at least on macOS Sequoia 15.1.1.
madsmtm
added
DS - macos
B - crash
kchibisov
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that referenced
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Dec 16, 2024
`AnyClass::responds_to` delegates to `class_respondsToSelector`, a function provided by the Objective-C runtime. However, at some point, this began to return `false` for selectors referring to undocumented cursors, despite the cursors remaining accessible via said selectors. That this check fails prevents the cursors from being used. We can instead send `respondsToSelector:` to the `NSCursor` class itself. As an instance method, this is nominally impossible; however, Apple grants an exemption[1] that permits class objects to perform instance methods defined in the root class. Checking for the undocumented cursors in this way gets them working again, at least on macOS Sequoia 15.1.1. [1]: https://developer.apple.com/library/archive/documentation/Cocoa/Conceptual/ObjectiveC/Chapters/ocObjectsClasses.html#//apple_ref/doc/uid/TP30001163-CH11-TPXREF120
kchibisov
pushed a commit
that referenced
this pull request
Dec 16, 2024
`AnyClass::responds_to` delegates to `class_respondsToSelector`, a function provided by the Objective-C runtime. However, at some point, this began to return `false` for selectors referring to undocumented cursors, despite the cursors remaining accessible via said selectors. That this check fails prevents the cursors from being used. We can instead send `respondsToSelector:` to the `NSCursor` class itself. As an instance method, this is nominally impossible; however, Apple grants an exemption[1] that permits class objects to perform instance methods defined in the root class. Checking for the undocumented cursors in this way gets them working again, at least on macOS Sequoia 15.1.1. [1]: https://developer.apple.com/library/archive/documentation/Cocoa/Conceptual/ObjectiveC/Chapters/ocObjectsClasses.html#//apple_ref/doc/uid/TP30001163-CH11-TPXREF120
kchibisov
pushed a commit
that referenced
this pull request
Dec 21, 2024
`AnyClass::responds_to` delegates to `class_respondsToSelector`, a function provided by the Objective-C runtime. However, at some point, this began to return `false` for selectors referring to undocumented cursors, despite the cursors remaining accessible via said selectors. That this check fails prevents the cursors from being used. We can instead send `respondsToSelector:` to the `NSCursor` class itself. As an instance method, this is nominally impossible; however, Apple grants an exemption[1] that permits class objects to perform instance methods defined in the root class. Checking for the undocumented cursors in this way gets them working again, at least on macOS Sequoia 15.1.1. [1]: https://developer.apple.com/library/archive/documentation/Cocoa/Conceptual/ObjectiveC/Chapters/ocObjectsClasses.html#//apple_ref/doc/uid/TP30001163-CH11-TPXREF120
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AnyClass::responds_todelegates toclass_respondsToSelector, a function provided by the Objective-C runtime. However, at some point, this began to returnfalsefor selectors referring to undocumented cursors, despite the cursors remaining accessible via said selectors. That this check fails prevents the cursors from being used.We can instead send
respondsToSelector:to theNSCursorclass itself. As an instance method, this is nominally impossible; however, Apple grants an exemption that permits class objects to perform instance methods defined in the root class.Checking for the undocumented cursors in this way gets them working again, at least on macOS Sequoia 15.1.1.
changelogmodule if knowledge of this change could be valuable to usersThis is my first contribution to winit so please let me know if I missed anything! cc @madsmtm
This should fix #3724.