[UIKit] Add nullability to file

[haritha-mohan]

File did not have nullability enabled. Add nullability and made some changes to code as safeguards.

[mandel-macaque]

Approving as long as the changes requested by @rolfbjarne are done.

[haritha-mohan]

Didn't catch a build issue, will commit working version once fixed

[vs-mobiletools-engineering-service2]

💻 [PR Build] Tests on macOS Mac Catalina (10.15) passed 💻

✅ All tests on macOS Mac Catalina (10.15) passed.

Pipeline on Agent
Hash: 8e7c67fcfd0d2b29610572ea3d67f61e3ab6685b [PR build]

[vs-mobiletools-engineering-service2]

📚 [PR Build] Artifacts 📚

Packages generated

View packages

• Microsoft.iOS.Bundle.15.4.394-ci.pr.gh15857.pkg
• Microsoft.iOS.Ref.15.4.394-ci.pr.gh15857.nupkg
• Microsoft.iOS.Runtime.ios-arm.15.4.394-ci.pr.gh15857.nupkg
• Microsoft.iOS.Runtime.ios-arm64.15.4.394-ci.pr.gh15857.nupkg
• Microsoft.iOS.Runtime.iossimulator-arm64.15.4.394-ci.pr.gh15857.nupkg
• Microsoft.iOS.Runtime.iossimulator-x64.15.4.394-ci.pr.gh15857.nupkg
• Microsoft.iOS.Runtime.iossimulator-x86.15.4.394-ci.pr.gh15857.nupkg
• Microsoft.iOS.Sdk.15.4.394-ci.pr.gh15857.nupkg
• Microsoft.iOS.Templates.15.4.394-ci.pr.gh15857.nupkg
• Microsoft.iOS.Windows.Sdk.15.4.394-ci.pr.gh15857.nupkg
• Microsoft.MacCatalyst.Bundle.15.4.394-ci.pr.gh15857.pkg
• Microsoft.MacCatalyst.Ref.15.4.394-ci.pr.gh15857.nupkg
• Microsoft.MacCatalyst.Runtime.maccatalyst-arm64.15.4.394-ci.pr.gh15857.nupkg
• Microsoft.MacCatalyst.Runtime.maccatalyst-x64.15.4.394-ci.pr.gh15857.nupkg
• Microsoft.MacCatalyst.Sdk.15.4.394-ci.pr.gh15857.nupkg
• Microsoft.MacCatalyst.Templates.15.4.394-ci.pr.gh15857.nupkg
• Microsoft.macOS.Bundle.12.3.394-ci.pr.gh15857.pkg
• Microsoft.macOS.Ref.12.3.394-ci.pr.gh15857.nupkg
• Microsoft.macOS.Runtime.osx-arm64.12.3.394-ci.pr.gh15857.nupkg
• Microsoft.macOS.Runtime.osx-x64.12.3.394-ci.pr.gh15857.nupkg
• Microsoft.macOS.Sdk.12.3.394-ci.pr.gh15857.nupkg
• Microsoft.macOS.Templates.12.3.394-ci.pr.gh15857.nupkg
• Microsoft.NET.Sdk.iOS.Manifest-6.0.300.15.4.394-ci.pr.gh15857.nupkg
• Microsoft.NET.Sdk.MacCatalyst.Manifest-6.0.300.15.4.394-ci.pr.gh15857.nupkg
• Microsoft.NET.Sdk.macOS.Manifest-6.0.300.12.3.394-ci.pr.gh15857.nupkg
• Microsoft.NET.Sdk.tvOS.Manifest-6.0.300.15.4.394-ci.pr.gh15857.nupkg
• Microsoft.NET.Workload.iOS.15.4.394-ci.pr.gh15857.msi
• Microsoft.tvOS.Bundle.15.4.394-ci.pr.gh15857.pkg
• Microsoft.tvOS.Ref.15.4.394-ci.pr.gh15857.nupkg
• Microsoft.tvOS.Runtime.tvos-arm64.15.4.394-ci.pr.gh15857.nupkg
• Microsoft.tvOS.Runtime.tvossimulator-arm64.15.4.394-ci.pr.gh15857.nupkg
• Microsoft.tvOS.Runtime.tvossimulator-x64.15.4.394-ci.pr.gh15857.nupkg
• Microsoft.tvOS.Sdk.15.4.394-ci.pr.gh15857.nupkg
• Microsoft.tvOS.Templates.15.4.394-ci.pr.gh15857.nupkg
• xamarin.ios-15.13.0.90.pkg
• xamarin.mac-8.13.0.90.pkg

Pipeline on Agent XAMBOT-1042.Monterey'
Hash: 8e7c67fcfd0d2b29610572ea3d67f61e3ab6685b [PR build]

[vs-mobiletools-engineering-service2]

💻 [PR Build] Tests on macOS M1 - Mac Big Sur (11.5) passed 💻

✅ All tests on macOS M1 - Mac Big Sur (11.5) passed.

Pipeline on Agent
Hash: 8e7c67fcfd0d2b29610572ea3d67f61e3ab6685b [PR build]

[vs-mobiletools-engineering-service2]

✅ API diff for current PR / commit

Legacy Xamarin (No breaking changes)

• iOS (no change detected)
• tvOS (no change detected)
• watchOS (no change detected)
• macOS (no change detected)

NET (empty diffs)

• iOS: (empty diff detected)
• tvOS: (empty diff detected)
• MacCatalyst: (empty diff detected)
• macOS: (empty diff detected)

✅ API diff vs stable

Legacy Xamarin (No breaking changes)

• iOS: vsdrops gist (No breaking changes)
• tvOS: vsdrops gist (No breaking changes)
• watchOS: vsdrops gist (No breaking changes)
• macOS: vsdrops gist (No breaking changes)

.NET (No breaking changes)

• iOS: vsdrops gist (No breaking changes)
• tvOS: vsdrops gist (No breaking changes)
• MacCatalyst: vsdrops gist (No breaking changes)
• macOS: vsdrops gist (No breaking changes)
• Microsoft.iOS vs Microsoft.MacCatalyst: vsdrops gist

Legacy Xamarin (stable) vs .NET

• iOS: vsdrops gist
• tvOS: vsdrops gist
• macOS: vsdrops gist

✅ Generator diff

Generator diff is empty

Pipeline on Agent
Hash: 8e7c67fcfd0d2b29610572ea3d67f61e3ab6685b [PR build]

[vs-mobiletools-engineering-service2]

🔥 [CI Build] Test results 🔥

Test results

❌ Tests failed on VSTS: simulator tests

0 tests crashed, 4 tests failed, 219 tests passed.

Failures

❌ linker tests

2 tests failed, 63 tests passed.

• dont link/Mac Catalyst [dotnet]/Debug [dotnet]: BuildFailure
• link sdk/iOS Unified 64-bits - simulator/Debug: LaunchFailure

Html Report (VSDrops) Download

❌ monotouch tests

1 tests failed, 22 tests passed.

• monotouch-test/watchOS 32-bits - simulator/Debug (static registrar): TimedOut

Html Report (VSDrops) Download

❌ msbuild tests

1 tests failed, 1 tests passed.

• MSBuild tests/Tasks: BuildFailure

Html Report (VSDrops) Download

Successes

✅ bcl: All 69 tests passed. Html Report (VSDrops) Download
✅ cecil: All 1 tests passed. Html Report (VSDrops) Download
✅ dotnettests: All 1 tests passed. Html Report (VSDrops) Download
✅ fsharp: All 7 tests passed. Html Report (VSDrops) Download
✅ framework: All 8 tests passed. Html Report (VSDrops) Download
✅ generator: All 2 tests passed. Html Report (VSDrops) Download
✅ interdependent_binding_projects: All 7 tests passed. Html Report (VSDrops) Download
✅ install_source: All 1 tests passed. Html Report (VSDrops) Download
✅ introspection: All 8 tests passed. Html Report (VSDrops) Download
✅ mac_binding_project: All 1 tests passed. Html Report (VSDrops) Download
✅ mmp: All 2 tests passed. Html Report (VSDrops) Download
✅ mononative: All 12 tests passed. Html Report (VSDrops) Download
✅ mtouch: All 1 tests passed. Html Report (VSDrops) Download
✅ xammac: All 3 tests passed. Html Report (VSDrops) Download
✅ xcframework: All 8 tests passed. Html Report (VSDrops) Download
✅ xtro: All 2 tests passed. Html Report (VSDrops) Download

Pipeline on Agent
Hash: [PR build]

[mandel-macaque]

Tests failures:

• Linker tests fail in just a single configuration and is not related to the change.
• MSBuild tests fail due to a network issue when fetching nugets.

None are related with the change.

[mandel-macaque]

/sudo backport xcode14

[vs-mobiletools-engineering-service2]

Backport Job to branch xcode14 Created! The magic is happening here

[vs-mobiletools-engineering-service2]

Hooray! Backport succeeded! Please see https://devdiv.visualstudio.com/DevDiv/_build/results?buildId=6658871 for more details.