[dotnet] Annotate nullability on DevTools and event args

[RenderMichael]

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Annotate nullability on DevTools and event args

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

• Annotated nullability across multiple classes and interfaces.

• Improved exception handling with specific exception types.

• Refactored and optimized code for better readability and maintainability.

• Added constructors and updated properties for better initialization and null safety.

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Changes walkthrough 📝

	Relevant files
Enhancement	18 files ChromiumOptions.cs Updated method and dictionary to support nullable objects. +2/-2      DevToolsSession.cs Added exception handling and nullability annotations.        +5/-0      DevToolsVersionInfo.cs Enabled nullability and added null checks for properties. +36/-16  ICommand.cs Enabled nullability and simplified interface definitions. +5/-10    IDevTools.cs Added nullability annotations and exception documentation. +3/-0      IDevToolsSession.cs Added exception handling and nullability annotations.        +5/-1      WebSocketConnection.cs Refactored for null safety and improved exception handling. +21/-11  V130Network.cs Refactored HTTP request and response handling for clarity. +22/-27  V131Network.cs Refactored HTTP request and response handling for clarity. +22/-27  V132Network.cs Refactored HTTP request and response handling for clarity. +22/-27  V85Network.cs Refactored HTTP request and response handling for clarity. +22/-27  DomMutatedEventArgs.cs Enabled nullability for better type safety.                            +2/-0      DomMutationData.cs Added nullability annotations and default initializations. +7/-5      DriverOptionsMergeResult.cs Added nullability annotations for conflict option name.    +5/-3      DriverProcessStartedEventArgs.cs Refactored for null safety and added exception handling.  +16/-21  DriverProcessStartingEventArgs.cs Added nullability annotations and exception handling.        +5/-7      HttpRequestData.cs Added constructor and nullability annotations for initialization. +22/-3    HttpResponseData.cs Added constructor and nullability annotations for initialization. +27/-15
Bug fix	2 files JsonEnumMemberConverter.cs Added null-forgiving operator to prevent null warnings.    +1/-1      DriverCommand.cs Fixed typo in command description and enabled nullability. +4/-1
Additional files	12 files HttpResponseContent.cs +4/-1      IActionExecutor.cs +5/-0      IAllowsFileDetection.cs +5/-0      IHasCommandExecutor.cs +2/-0      ITargetLocator.cs +1/-0      JavaScriptCallbackExecutedEventArgs.cs +2/-0      JavaScriptConsoleApiCalledEventArgs.cs +4/-2      JavaScriptExceptionThrownEventArgs.cs +2/-0      NetworkManager.cs +1/-1      NetworkRequestSentEventArgs.cs +10/-12  NetworkResponseReceivedEventArgs.cs +14/-17  Response.cs +2/-0

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PR Reviewer Guide 🔍

Here are some key observations to aid the review process:

⏱️ Estimated effort to review: 3 🔵🔵🔵⚪⚪

🧪 No relevant tests

🔒 No security concerns identified

⚡ Recommended focus areas for review Null Safety The constructor requires non-null parameters but doesn't validate them. Consider adding null checks for required parameters like requestId, url, and resourceType. public HttpResponseData(string requestId, string url, string resourceType, long statusCode, string? errorReason) { RequestId = requestId; Url = url; ResourceType = resourceType; StatusCode = statusCode; ErrorReason = errorReason; } Potential Bug Creating HttpRequestData with all null parameters could cause issues. Consider creating a more appropriate constructor or method for this use case. HttpRequestData requestData = new HttpRequestData(null, null, null, null, requestId: e.ResponseData.RequestId);

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PR Code Suggestions ✨

Explore these optional code suggestions:

Category	Suggestion	Impact
Possible issue	Fix null parameter violation Avoid passing null values to the HttpRequestData constructor as it violates the constructor's non-null parameter constraints. Instead, use empty strings or empty collections for required parameters. dotnet/src/webdriver/NetworkManager.cs [265] -HttpRequestData requestData = new HttpRequestData(null, null, null, null, requestId: e.ResponseData.RequestId); +HttpRequestData requestData = new HttpRequestData(string.Empty, string.Empty, null, new Dictionary<string, string>(), e.ResponseData.RequestId); Apply this suggestion Suggestion importance[1-10]: 8 __ Why: The suggestion correctly identifies a potential runtime issue where null values are passed to a constructor that expects non-null parameters. The fix properly initializes required parameters with empty values.	Medium
	Add regex match validation Add null check for regex match groups before accessing values to prevent potential NullReferenceException if pattern doesn't match. dotnet/src/webdriver/DevTools/DevToolsVersionInfo.cs [53] -return Regex.Match(Browser, ".*/(.*)").Groups[1].Value; +var match = Regex.Match(Browser, ".*/(.*)"); +if (!match.Success || match.Groups.Count < 2) + throw new InvalidOperationException("Invalid browser version format"); +return match.Groups[1].Value; Apply this suggestion Suggestion importance[1-10]: 7 __ Why: The suggestion adds important validation for regex match success and group count, which could prevent runtime exceptions if the Browser string doesn't match the expected format.	Medium
	Add null check for safety The null-forgiving operator (!) is used without verifying if GetField() returns null, which could cause a NullReferenceException. Add a null check before accessing the field. dotnet/src/webdriver/DevTools/Json/JsonEnumMemberConverter.cs [47] -var enumMember = type.GetField(value.ToString())!; +var enumMember = type.GetField(value.ToString()) ?? throw new InvalidOperationException($"Enum field {value} not found in type {type.Name}"); Apply this suggestion Suggestion importance[1-10]: 7 __ Why: The suggestion addresses a potential NullReferenceException by replacing the null-forgiving operator with a proper null check and meaningful exception message, improving error handling and debugging.	Medium
	Add null check for buffer array Add null check for buffer.Array before using it in ReceiveData() method to prevent potential NullReferenceException when creating the buffer. dotnet/src/webdriver/DevTools/WebSocketConnection.cs [268] -messageBuilder.Append(Encoding.UTF8.GetString(buffer.Array!, 0, receiveResult.Count)); +if (buffer.Array is null) throw new InvalidOperationException("WebSocket buffer array is null"); +messageBuilder.Append(Encoding.UTF8.GetString(buffer.Array, 0, receiveResult.Count)); Apply this suggestion Suggestion importance[1-10]: 3 __ Why: The suggestion is valid but unnecessary since the code already uses the null-forgiving operator (!), indicating that the developer has already considered and handled this case.	Low

[RenderMichael]

From automated PR review:

The constructor requires non-null parameters but doesn't validate them. Consider adding null checks for required parameters like requestId, url, and resourceType.

Every non-nullable parameter which doesn't get validated is intentionally so. Each of those values comes from the CDP responses. Values are marked as optional/non-optional in the protocol spec, but I do not want Selenium to be the problem which comes inbetween an accidentally null value.

[RenderMichael]

Test failures are unrelated to this PR

//java/test/org/openqa/selenium/mobile:NetworkConnectionTest
//java/test/org/openqa/selenium/remote:RemoteWebDriverScreenshotTest
//java/test/org/openqa/selenium/remote:RemoteWebDriverScreenshotTest-firefox-beta
//rb/spec/integration/selenium/webdriver:network-firefox-beta-bidi
//rb/spec/integration/selenium/webdriver:network-firefox-bidi