[dotnet] Annotate nullable reference types on input devices

[RenderMichael]

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Description

Annotates nullable reference types on InputDevice and derived types. Implement modernization, simplification, and more XML documentation along the way.

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, documentation

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Description

• Enabled nullable reference types across multiple input device classes to improve null safety.
• Modernized code by using auto-properties and expression-bodied members for simplicity.
• Added XML documentation for constructors to specify exceptions thrown.
• Improved exception handling and documentation for better code clarity and maintenance.

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Changes walkthrough 📝

Relevant files

Enhancement

InputDevice.cs Annotate nullable types and modernize InputDevice class    dotnet/src/webdriver/Interactions/InputDevice.cs Enabled nullable reference types. Replaced field with auto-property for DeviceName. Simplified method implementations using expression-bodied members. Added XML documentation for exceptions. +8/-16    KeyInputDevice.cs Annotate nullable types and simplify KeyInputDevice            dotnet/src/webdriver/Interactions/KeyInputDevice.cs Enabled nullable reference types. Simplified property and method implementations. Added XML documentation for exceptions. +10/-14  PointerInputDevice.cs Enhance PointerInputDevice with nullable annotations          dotnet/src/webdriver/Interactions/PointerInputDevice.cs Enabled nullable reference types. Converted fields to readonly where applicable. Simplified property and method implementations. Improved exception handling and documentation. +60/-114 WheelInputDevice.cs Enhance WheelInputDevice with nullable annotations              dotnet/src/webdriver/Interactions/WheelInputDevice.cs Enabled nullable reference types. Converted fields to readonly where applicable. Simplified property and method implementations. Improved exception handling and documentation. +23/-50

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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 ToString() method assumes target is not null when origin is CoordinateOrigin.Element. This could cause NullReferenceException if target is null. Code Duplication The ConvertElement() method is duplicated between PointerInputDevice and WheelInputDevice classes. Consider extracting to a shared helper class.

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PR Code Suggestions ✨

Explore these optional code suggestions:

Category	Suggestion	Score
Possible issue	Add parameter validation to prevent null reference exceptions Add null check for properties parameter in the constructor to avoid potential NullReferenceException when accessing eventProperties later. dotnet/src/webdriver/Interactions/PointerInputDevice.cs [427-432] public PointerDownInteraction(InputDevice sourceDevice, MouseButton button, PointerEventProperties properties) : base(sourceDevice) { this.button = button; - this.eventProperties = properties; + this.eventProperties = properties ?? throw new ArgumentNullException(nameof(properties)); } Apply this suggestion Suggestion importance[1-10]: 8 Why: Adding null validation for the properties parameter is crucial as it prevents potential NullReferenceException in the ToDictionary method where eventProperties is used.	8
	Add null check for required parameter to prevent runtime errors Add null check for target parameter in ConvertElement() since it's marked as nullable but the method assumes it's non-null. dotnet/src/webdriver/Interactions/PointerInputDevice.cs [584-588] private Dictionary<string, object> ConvertElement() { + if (this.target == null) + { + throw new ArgumentNullException(nameof(target)); + } if (this.target is IWebDriverObjectReference element) { return element.ToDictionary(); } Apply this suggestion Suggestion importance[1-10]: 7 Why: The ConvertElement method assumes target is non-null but it's marked as nullable. Adding an explicit null check improves error handling and prevents runtime exceptions.	7

💡 Need additional feedback ? start a PR chat

[nvborisenko]

Not for method, topic for editorconfig.

[RenderMichael]

Do you think we need a consistent rule here? I like to use method expressions if the method contains no real logic, just alternate parameters or for a wrapper.

If we want to always use method bodies, I can revert this change.

[nvborisenko]

Yes please revert, for methods. This question is out of scope of this PR.

[nvborisenko]

I like to use method expressions if the method contains no real logic, just alternate parameters or for a wrapper.

I like to preserve a placeholder via { } to add more code inside when a method becomes to not if the method contains no real logic.

It is more for internal conventions (editorconfig topic), at this time let us be less destructive.

[RenderMichael]

I completely get that, it allows for much smaller diffs. I'll try to stick to that convention. The editorconfig PR is updated with the latest thinking btw :)

[nvborisenko]

So modernized! I am old-school (I am not alone).

[RenderMichael]

I remember I used to jump on every modern innovation, and turn code into a mess just to use new features. These days I pick and choose.

I really like the property pattern matching personally, this method is now much shorter.