[Foundation] Fix nullability in NSObject. #24481

rolfbjarne · 2026-01-05T09:41:19Z

This is file 43 of 47 files with nullability disabled in Foundation.

Enables nullability.
Removes SupportedOSPlatform attributes without version numbers from NSObject and NSObservedChange classes.
Replaces XML include attributes with inlined content from NSObjectFlag.xml and NSObservedChange.xml.
Removes 'To be added' XML comments with proper documentation.
Adds missing XML documentation for public and protected members.
Improves XML comments for language, grammar, consistency and correctness.
Adds see cref attributes for type and member references.
Removes unnecessary whitespace in XML comments.

Contributes towards #17285.

This is file 43 of 47 files with nullability disabled in Foundation. * Enables nullability. * Removes SupportedOSPlatform attributes without version numbers from NSObject and NSObservedChange classes. * Replaces XML include attributes with inlined content from NSObjectFlag.xml and NSObservedChange.xml. * Removes 'To be added' XML comments with proper documentation. * Adds missing XML documentation for public and protected members. * Improves XML comments for language, grammar, consistency and correctness. * Adds see cref attributes for type and member references. * Removes unnecessary whitespace in XML comments. Contributes towards #17285.

Copilot

Pull request overview

This PR enables nullable reference types for the NSObject class in Foundation, which is a critical component of the .NET for iOS/Mac/tvOS bindings. The changes ensure proper null safety throughout the Foundation framework by fixing nullability annotations and improving documentation quality.

Enables #nullable enable in NSObject2.cs and removes redundant #nullable directives throughout the file
Updates method signatures to properly reflect nullable return types (e.g., ToString() now returns string?)
Improves XML documentation by inlining content from external XML files and replacing "To be added" placeholders with detailed descriptions

Reviewed changes

Copilot reviewed 15 out of 15 changed files in this pull request and generated 4 comments.

Show a summary per file

File	Description
src/Foundation/NSObject2.cs	Enables nullability, inlines XML documentation from external files, adds comprehensive documentation for NSObjectFlag and NSObservedChange classes, and updates method signatures with proper nullable annotations
src/Foundation/NSUrlRequest.cs	Updates `ToString()` return type to nullable `string?` to match base class nullability
src/Foundation/NSUrl.cs	Updates `ToString()` return type to nullable `string?` to match base class nullability
src/Foundation/NSString.cs	Adds null-forgiving operator for `NSObject.FromObject()` call since the result is guaranteed non-null for non-null input
src/Foundation/NSSet.cs	Updates `Contains()` to accept nullable parameters and handle null inputs correctly
src/Foundation/NSOrderedSet.cs	Updates `Contains()` to accept nullable parameters and handle null inputs correctly
src/Foundation/NSAction.cs	Updates internal dispatcher classes to accept nullable state parameters
src/Foundation/DictionaryContainer.cs	Adds null-forgiving operator for `NSObject.FromObject()` call in array conversion
src/CoreImage/CIDetectorOptions.cs	Adds null-forgiving operators for `NSObject.FromObject()` calls with value types that cannot be null
src/CoreFoundation/CFException.cs	Adds null-coalescing operators to handle nullable `ToString()` results when populating exception data
src/CoreBluetooth/CBUUID.cs	Updates `Equals()` parameter to accept nullable `object?`
src/AppKit/NSColor.cs	Updates `ToString()` return type to nullable `string?` to match base class nullability
docs/api/Foundation/NSObservedChange.xml	Removed - content inlined into NSObject2.cs
docs/api/Foundation/NSObjectFlag.xml	Removed - content inlined into NSObject2.cs
tests/cecil-tests/Documentation.KnownFailures.txt	Removes `SetValueForKeyPath(NativeHandle, NSString)` from known failures list as it now has proper documentation

src/Foundation/NSObject2.cs

Co-authored-by: Copilot <[email protected]>

vs-mobiletools-engineering-service2 · 2026-01-05T11:14:10Z

✅ [CI Build #b257485] Build passed (Build packages) ✅

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vs-mobiletools-engineering-service2 · 2026-01-05T11:52:45Z

✅ [CI Build #b257485] Build passed (Build macOS tests) ✅

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vs-mobiletools-engineering-service2 · 2026-01-06T08:14:50Z

✅ [PR Build #b257485] Build passed (Detect API changes) ✅

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vs-mobiletools-engineering-service2 · 2026-01-06T08:42:43Z

✅ API diff for current PR / commit

NET (empty diffs)

iOS: vsdrops gist ( No breaking changes )
tvOS: vsdrops gist ( No breaking changes )
MacCatalyst: vsdrops gist ( No breaking changes )
macOS: vsdrops gist ( No breaking changes )

✅ API diff vs stable

NET (empty diffs)

iOS: vsdrops gist ( No breaking changes )
tvOS: vsdrops gist ( No breaking changes )
MacCatalyst: vsdrops gist ( No breaking changes )
macOS: vsdrops gist ( No breaking changes )

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Generator Diff: vsdrops (html) vsdrops (raw diff) gist (raw diff) - Please review changes)

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vs-mobiletools-engineering-service2 · 2026-01-08T09:57:32Z

💻 [CI Build #b257485] Tests on macOS arm64 - Mac Tahoe (26) passed 💻

✅ All tests on macOS arm64 - Mac Tahoe (26) passed.

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Hash: b257485a3e359d2e313723b1327e46a62cb11f86 [PR build]

vs-mobiletools-engineering-service2 · 2026-01-08T10:01:58Z

🚀 [CI Build #b257485] Test results 🚀

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✅ All tests passed on VSTS: test results.

🎉 All 117 tests passed 🎉

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✅ cecil: All 1 tests passed. Html Report (VSDrops) Download
✅ dotnettests (iOS): All 1 tests passed. Html Report (VSDrops) Download
✅ dotnettests (MacCatalyst): All 1 tests passed. Html Report (VSDrops) Download
✅ dotnettests (macOS): All 1 tests passed. Html Report (VSDrops) Download
✅ dotnettests (Multiple platforms): All 1 tests passed. Html Report (VSDrops) Download
✅ dotnettests (tvOS): All 1 tests passed. Html Report (VSDrops) Download
✅ framework: All 2 tests passed. [attempt 2] Html Report (VSDrops) Download
✅ fsharp: All 4 tests passed. Html Report (VSDrops) Download
✅ generator: All 5 tests passed. Html Report (VSDrops) Download
✅ interdependent-binding-projects: All 4 tests passed. Html Report (VSDrops) Download
✅ introspection: All 4 tests passed. Html Report (VSDrops) Download
✅ linker: All 44 tests passed. Html Report (VSDrops) Download
✅ monotouch (iOS): All 9 tests passed. Html Report (VSDrops) Download
✅ monotouch (MacCatalyst): All 11 tests passed. Html Report (VSDrops) Download
✅ monotouch (macOS): All 9 tests passed. Html Report (VSDrops) Download
✅ monotouch (tvOS): All 9 tests passed. Html Report (VSDrops) Download
✅ msbuild: All 2 tests passed. Html Report (VSDrops) Download
✅ windows: All 3 tests passed. Html Report (VSDrops) Download
✅ xcframework: All 4 tests passed. Html Report (VSDrops) Download
✅ xtro: All 1 tests passed. Html Report (VSDrops) Download

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rolfbjarne requested a review from dalexsoto as a code owner January 5, 2026 09:41

rolfbjarne requested a review from Copilot January 5, 2026 09:41

Copilot started reviewing on behalf of rolfbjarne January 5, 2026 09:42 View session

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rolfbjarne and others added 4 commits January 5, 2026 11:30

Update src/Foundation/NSObject2.cs

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Co-authored-by: Copilot <[email protected]>

Update src/Foundation/NSObject2.cs

e7a4b18

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Update src/Foundation/NSObject2.cs

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Co-authored-by: Copilot <[email protected]>

Update src/Foundation/NSObject2.cs

b257485

Co-authored-by: Copilot <[email protected]>

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dalexsoto approved these changes Jan 5, 2026

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rolfbjarne enabled auto-merge (squash) January 6, 2026 07:58

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rolfbjarne merged commit 6ee9375 into main Jan 8, 2026
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[Foundation] Fix nullability in NSObject. #24481

[Foundation] Fix nullability in NSObject. #24481

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vs-mobiletools-engineering-service2 commented Jan 5, 2026

✅ [CI Build #b257485] Build passed (Build packages) ✅

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vs-mobiletools-engineering-service2 commented Jan 5, 2026

✅ [CI Build #b257485] Build passed (Build macOS tests) ✅

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vs-mobiletools-engineering-service2 commented Jan 6, 2026

✅ [PR Build #b257485] Build passed (Detect API changes) ✅

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vs-mobiletools-engineering-service2 commented Jan 8, 2026

💻 [CI Build #b257485] Tests on macOS arm64 - Mac Tahoe (26) passed 💻

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🚀 [CI Build #b257485] Test results 🚀

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