[dotnet] Add nullability to Alerts

[RenderMichael]

Description

Adds NRT annotations to the IAlert type and its implementations.

Contributes to #14640

For methods that currently throw an exception of null is passed, that has been replaced with argument validation ahead of time. Likewise for as casts that would be null references. Other than that, no behavior changes are present.

Motivation and Context

Nullable reference types aim to fix the billion dollar mistake.

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, error handling

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Description

• Enabled nullable reference types across multiple classes and interfaces to improve null safety.
• Added ArgumentNullException checks for methods that accept nullable parameters to enhance error handling.
• Updated constructors and methods to handle nullable strings and objects, ensuring better null management.
• Improved documentation comments to reflect nullable parameters and exceptions.

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PRDescriptionHeader.CHANGES_WALKTHROUGH

Relevant files

Enhancement

18 files Alert.cs Enable nullable reference types and improve null handling in Alert class dotnet/src/webdriver/Alert.cs Enabled nullable reference types. Added null-forgiving operator to commandResponse.Value.ToString(). Added ArgumentNullException for SendKeys method. +5/-2      Cookie.cs Enable nullable reference types and improve null handling in Cookie class dotnet/src/webdriver/Cookie.cs Enabled nullable reference types. Updated constructors and methods to handle nullable strings. Added ArgumentNullException for null dictionary in FromDictionary. +26/-23  CookieJar.cs Enable nullable reference types and improve null handling in CookieJar class dotnet/src/webdriver/CookieJar.cs Enabled nullable reference types. Added ArgumentNullException for null parameters. Updated methods to handle nullable strings and objects. +17/-9    ICookieJar.cs Enable nullable reference types and update ICookieJar interface dotnet/src/webdriver/ICookieJar.cs Enabled nullable reference types. Updated interface methods to handle nullable parameters. +7/-3      ILogs.cs Enable nullable reference types and improve error handling in ILogs interface dotnet/src/webdriver/ILogs.cs Enabled nullable reference types. Added ArgumentNullException for GetLog method. +4/-0      INetwork.cs Enable nullable reference types and improve null handling in INetwork interface dotnet/src/webdriver/INetwork.cs Enabled nullable reference types. Updated event handlers to be nullable. Added ArgumentNullException for AddRequestHandler. +5/-2      IOptions.cs Enable nullable reference types in IOptions interface        dotnet/src/webdriver/IOptions.cs Enabled nullable reference types. +2/-0      ITargetLocator.cs Enable nullable reference types and improve error handling in ITargetLocator interface dotnet/src/webdriver/ITargetLocator.cs Enabled nullable reference types. Added ArgumentNullException for Window method. +3/-0      ITimeouts.cs Enable nullable reference types in ITimeouts interface      dotnet/src/webdriver/ITimeouts.cs Enabled nullable reference types. +2/-0      IWindow.cs Enable nullable reference types in IWindow interface          dotnet/src/webdriver/IWindow.cs Enabled nullable reference types. +2/-0      ReturnedCookie.cs Enable nullable reference types and update ReturnedCookie class dotnet/src/webdriver/Internal/ReturnedCookie.cs Enabled nullable reference types. Updated constructor parameters to handle nullable strings. +4/-2      LogEntry.cs Enable nullable reference types and improve error handling in LogEntry class dotnet/src/webdriver/LogEntry.cs Enabled nullable reference types. Added ArgumentNullException for FromDictionary method. +15/-6    Logs.cs Enable nullable reference types and improve error handling in Logs class dotnet/src/webdriver/Logs.cs Enabled nullable reference types. Added ArgumentNullException for GetLog method. +12/-4    NetworkManager.cs Enable nullable reference types and improve null handling in NetworkManager class dotnet/src/webdriver/NetworkManager.cs Enabled nullable reference types. Updated event handlers to be nullable. Added ArgumentNullException for AddRequestHandler. +7/-4      OptionsManager.cs Enable nullable reference types in OptionsManager class    dotnet/src/webdriver/OptionsManager.cs Enabled nullable reference types. +2/-0      TargetLocator.cs Enable nullable reference types and improve error handling in TargetLocator class dotnet/src/webdriver/TargetLocator.cs Enabled nullable reference types. Added ArgumentNullException for Frame and Window methods. +20/-6    Timeouts.cs Enable nullable reference types in Timeouts class                dotnet/src/webdriver/Timeouts.cs Enabled nullable reference types. +2/-0      Window.cs Enable nullable reference types and update Window class    dotnet/src/webdriver/Window.cs Enabled nullable reference types. Updated dictionary parameters to be nullable. +5/-3

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[qodo-code-review]

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 Possible Bug The SameSite property is now nullable, but the validation logic in the constructor has not been updated to handle null values. This could lead to unexpected behavior. Type Safety The cast to PasswordCredentials on line 205 is not checked. If authenticationHandler.Credentials is not of type PasswordCredentials, this could lead to a runtime exception. Error Handling The Window method catches NoSuchWindowException but then attempts to search by name without re-throwing if the search fails. This could mask the original exception and make debugging difficult.

[qodo-code-review]

PR Code Suggestions ✨

Explore these optional code suggestions:

Category	Suggestion	Score
Enhancement	Use pattern matching for more idiomatic type checking and casting Use pattern matching with 'is' keyword for a more idiomatic C# approach to type checking and casting. dotnet/src/webdriver/NetworkManager.cs [49-53] -IDevTools? devToolsDriver = driver as IDevTools; -if (devToolsDriver == null) +if (driver is not IDevTools devToolsDriver) { throw new WebDriverException("Driver must implement IDevTools to use these features"); } Apply this suggestion Suggestion importance[1-10]: 9 Why: This suggestion enhances the code by using pattern matching, which is a more idiomatic and modern C# approach for type checking and casting, improving both readability and maintainability.	9
	Simplify null checking using the null-coalescing operator Consider using the null-coalescing operator (??) instead of a ternary operator for a more concise null check. dotnet/src/webdriver/Cookie.cs [387] -return string.IsNullOrEmpty(domain) ? null : domain!.Split(':')[0]; +return domain?.Split(':')[0]; Apply this suggestion Suggestion importance[1-10]: 8 Why: The suggestion improves code readability and conciseness by using the null-coalescing operator, which is a more modern and idiomatic approach in C# for handling null checks.	8
	Use switch expression with pattern matching for more concise enum parsing Use a switch expression with pattern matching for a more concise and modern approach to parsing the log level. dotnet/src/webdriver/Logs.cs [105-114] -string? levelValue = entryDictionary["level"].ToString(); +entry.level = entryDictionary["level"].ToString() switch +{ + string s when Enum.TryParse<LogLevel>(s, ignoreCase: true, out var level) => level, + _ => LogLevel.All +}; -if (Enum.TryParse(levelValue, ignoreCase: true, out LogLevel level)) -{ - entry.level = level; -} -else -{ - // If the requested log level string is not a valid log level, - // ignore it and use LogLevel.All. -} - Apply this suggestion Suggestion importance[1-10]: 7 Why: The suggestion offers a more concise and modern approach to parsing enums using a switch expression with pattern matching, which can improve code readability and reduce potential errors.	7
Best practice	✅ Use null-conditional operator for safer null checking Suggestion Impact: The commit replaced the null-forgiving operator with a direct cast to a nullable string, which is a safer approach to null checking. code diff: - return commandResponse.Value.ToString()!; + return (string?)commandResponse.Value; Use the null-forgiving operator (!) only when absolutely necessary. Consider using the null-conditional operator (?.) for a safer approach to null checking. dotnet/src/webdriver/Alert.cs [50] -return commandResponse.Value.ToString()!; +return commandResponse.Value?.ToString() ?? string.Empty; Apply this suggestion Suggestion importance[1-10]: 8 Why: This suggestion enhances safety by using the null-conditional operator, which prevents potential null reference exceptions and improves code robustness.	8

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[nvborisenko]

Thanks @RenderMichael !