[dotnet] Annotate nullability on capabilities types

[RenderMichael]

User description

Description

Annotate nullability on capabilities types

Motivation and Context

Contributes to #14640

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist

• I have read the contributing document.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have added tests to cover my changes.
• All new and existing tests passed.

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PR Type

Enhancement

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Description

• Enabled nullable reference types in multiple files for better null safety.

• Updated method signatures and properties to support nullable types.

• Simplified logic using null-coalescing operators and pattern matching.

• Improved internal data structures with readonly collections and HashSet.

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Changes walkthrough 📝

Relevant files

Enhancement

IHasCapabilities.cs Enable nullable reference types in interface                          dotnet/src/webdriver/IHasCapabilities.cs Enabled nullable reference types. +2/-0      IWritableCapabilities.cs Enable nullable reference types in writable capabilities  dotnet/src/webdriver/IWritableCapabilities.cs Enabled nullable reference types. +2/-0      DesiredCapabilities.cs Improve null safety in DesiredCapabilities                              dotnet/src/webdriver/Remote/DesiredCapabilities.cs Updated constructor to accept nullable dictionary. Improved null safety in methods and properties. Simplified equality checks using pattern matching. +1/-1      ReadOnlyDesiredCapabilities.cs Enhance null safety in ReadOnlyDesiredCapabilities              dotnet/src/webdriver/Remote/ReadOnlyDesiredCapabilities.cs Enabled nullable reference types. Simplified property logic with null-coalescing operators. Improved dictionary handling with TryGetValue. Updated method signatures to support nullable types. +20/-40  RemoteSessionSettings.cs Improve null safety in RemoteSessionSettings                          dotnet/src/webdriver/Remote/RemoteSessionSettings.cs Enabled nullable reference types. Updated private fields to readonly or nullable. Improved dictionary and list handling with nullable types. Enhanced internal methods for null safety. +17/-14

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[qodo-code-review]

PR Reviewer Guide 🔍

Here are some key observations to aid the review process:

⏱️ Estimated effort to review: 2 🔵🔵⚪⚪⚪

🧪 No relevant tests

🔒 No security concerns identified

⚡ Recommended focus areas for review Null Reference The GetCapability method returns nullable object but AcceptInsecureCerts property assumes non-null when casting to bool. This could cause runtime exceptions. bool acceptSSLCerts = false; object? capabilityValue = this.GetCapability(CapabilityType.AcceptInsecureCertificates); if (capabilityValue != null) { acceptSSLCerts = (bool)capabilityValue; }

[qodo-code-review]

PR Code Suggestions ✨

Explore these optional code suggestions:

Category	Suggestion	Impact
Possible issue	Prevent potential invalid type casting Add null check before casting to bool to prevent potential InvalidCastException if capabilityValue is not a boolean. dotnet/src/webdriver/Remote/ReadOnlyDesiredCapabilities.cs [96-99] -if (capabilityValue != null) +if (capabilityValue is bool boolValue) { - acceptSSLCerts = (bool)capabilityValue; + acceptSSLCerts = boolValue; } Apply this suggestion Suggestion importance[1-10]: 8 __ Why: The suggestion improves type safety by using pattern matching instead of direct casting, preventing potential runtime InvalidCastException if capabilityValue is not a boolean type.	Medium
	Improve null safety handling Use pattern matching to safely handle null case in GetAlwaysMatchOptionsAsSerializableDictionary to prevent potential NullReferenceException. dotnet/src/webdriver/Remote/RemoteSessionSettings.cs [267-270] private IDictionary<string, object>? GetAlwaysMatchOptionsAsSerializableDictionary() { - return this.mustMatchDriverOptions?.ToDictionary(); + return this.mustMatchDriverOptions is DriverOptions options ? options.ToDictionary() : null; } Apply this suggestion Suggestion importance[1-10]: 4 __ Why: While the suggestion uses pattern matching for null checking, the existing null-conditional operator (?.) already provides adequate null safety. The improvement is mainly stylistic with minimal impact on functionality.	Low
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