chore(deps): update dependency polyfill to 8.9.0

[thomhurst]

This PR contains the following updates:

Package	Type	Update	Change
Polyfill	nuget	minor	8.8.1 -> 8.9.0

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Release Notes

SimonCropp/Polyfill (Polyfill)

v8.9.0

Compare Source

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Configuration

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[claude]

Claude finished @thomhurst's task —— View job

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PR Review: Polyfill Dependency Update

Reviewing this dependency update from Polyfill 8.8.1 → 8.9.0.

Todo List

• Examine the changed file (Directory.Packages.props)
• Analyze the Polyfill package and its purpose in TUnit
• Review changelog/release notes for 8.9.0
• Assess potential impact on TUnit codebase
• Check for security or breaking changes
• Provide comprehensive review feedback

Review Summary

✅ APPROVED - This is a safe, low-risk dependency update.

Code Quality & Best Practices

• Good: Package is properly configured with PrivateAssets="all" ensuring it's a build-time dependency only
• Good: Centralized package management via Directory.Packages.props
• Good: Consistent with TUnit's regular dependency update pattern (see recent commits)

Polyfill Usage Analysis

The Polyfill package serves a critical role in TUnit:

• File I/O Operations: Extensively used for FilePolyfill.ReadAllTextAsync() and FilePolyfill.WriteAllTextAsync() in source generator tests (TUnit.Core.SourceGenerator.Tests/)
• Cross-Framework Compatibility: Provides modern .NET APIs for older target frameworks (.NET Standard 2.0, .NET 6+)
• Conditional Integration: Configured via Polyfill.targets with EnableTUnitPolyfills flag
• Custom Extensions: Complements with TUnit.Engine/PolyfillExtensions.cs for string operations

Security & Performance Considerations

• ✅ Security: Minor version bump (8.8.1 → 8.9.0) with no breaking changes expected
• ✅ Performance: No performance impact as this is a compile-time polyfill package
• ✅ Compatibility: Maintains .NET Standard 2.0 support and AOT compatibility

Test Coverage Assessment

• Recommended: Run source generator tests to ensure polyfill changes don't affect file operations:

  dotnet test TUnit.Core.SourceGenerator.Tests

• Note: The package is heavily used in test infrastructure, particularly for file I/O in snapshot testing

Technical Impact

• Risk Level: LOW - Minor version update of a build-time dependency
• Breaking Changes: None expected for minor version bump
• Dependencies: No cascading updates required

Recommendation

✅ Approve and merge - This is a routine dependency maintenance update that aligns with TUnit's regular update cadence and poses minimal risk.

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