[dotnet] Add nullability annotations to devtools domains

[RenderMichael]

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Description

Add nullability annotations to devtools domains, as well as some event args I missed in a previous PR.

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, Bug fix

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Description

• Added nullability annotations to multiple DevTools-related classes.

• Improved immutability by replacing mutable properties with readonly or auto-properties.

• Enhanced exception handling and safety with nullability checks and improved constructors.

• Updated enum handling with conditional compilation for .NET 8.0 and above.

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Changes walkthrough 📝

	Relevant files
Enhancement	9 files DevToolsDomains.cs Added nullability annotations and improved constructor handling. +7/-10    DevToolsExtensionMethods.cs Enabled nullability annotations for extension methods.      +2/-0      DevToolsOptions.cs Enabled nullability annotations for DevTools options.        +2/-0      DevToolsSessionDomains.cs Added nullability annotations and improved immutability.  +3/-3      DevToolsSessionEventReceivedEventArgs.cs Added nullability annotations and made properties readonly. +5/-3      DevToolsSessionLogMessageEventArgs.cs Enabled nullability annotations for log message event args. +2/-0      ExceptionThrownEventArgs.cs Added nullability annotations and improved constructor usage. +15/-2    JsonEnumMemberConverter.cs Enhanced enum handling with nullability and .NET 8.0 support. +11/-4    ResponsePausedEventArgs.cs Enabled nullability annotations for response paused event args. +2/-0
Bug fix	4 files V130JavaScript.cs Improved exception handling with constructor-based initialization. +5/-5      V131JavaScript.cs Improved exception handling with constructor-based initialization. +5/-5      V132JavaScript.cs Improved exception handling with constructor-based initialization. +5/-5      V85JavaScript.cs Improved exception handling with constructor-based initialization. +5/-5

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[RenderMichael]

Since we know type is an enum, we know each of the values are fields.

[qodo-merge-pro]

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 code assumes constructor will not be null when calling GetConstructor() and using ! operator. Should add null check to handle case where constructor is not found. ConstructorInfo constructor = domainType.GetConstructor(new Type[] { typeof(DevToolsSession) })!; return (DevToolsDomains)constructor.Invoke(new object[] { session });

[qodo-merge-pro]

PR Code Suggestions ✨

Explore these optional code suggestions:

Category	Suggestion	Score
Possible issue	Add null check for domain type Add null check for domainType before accessing its constructor to prevent potential NullReferenceException if no matching domain type is found. dotnet/src/webdriver/DevTools/DevToolsDomains.cs [100-101] +if (domainType == null) + throw new ArgumentException("No matching domain type found for the specified version"); ConstructorInfo constructor = domainType.GetConstructor(new Type[] { typeof(DevToolsSession) })!; return (DevToolsDomains)constructor.Invoke(new object[] { session }); Apply this suggestion Suggestion importance[1-10]: 8 Why: The suggestion addresses a critical potential null reference exception that could occur if no matching domain type is found, improving the robustness of the code.	8
	Add null check for attribute value Add null check for attr before accessing its value to prevent potential NullReferenceException when processing enum members without EnumMemberAttribute. dotnet/src/webdriver/DevTools/Json/JsonEnumMemberConverter.cs [49-51] var attr = enumMember.GetCustomAttributes(typeof(EnumMemberAttribute), false) .Cast<EnumMemberAttribute>() .FirstOrDefault(); +if (attr?.Value == null) + continue; Apply this suggestion Suggestion importance[1-10]: 7 Why: The suggestion prevents potential null reference exceptions when processing enum members without EnumMemberAttribute, enhancing code stability.	7

[RenderMichael]

The existing code checks for missing constructors, but this can never be the case. We know the 4 possible domain types. All of them have the right constructor, and are an instance of the DevToolsDomains type.

Looking around at how this method is used, it is expected that the returned value is not null. Otherwise, we would be getting null reference exceptions.