[dotnet] Avoid performing JSON serialization in debugger display

[RenderMichael]

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Description

Inspired by conversion in #14726

Motivation and Context

The debugger display should provide a very brief snapshot of the object's values (the user can expand the object if they want to see everything). Performing JSON serialization is antithetical to that, and can result in performance issues.

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

• Added DebuggerDisplay attributes to DriverOptions, ReturnedCapabilities, and RemoteSessionSettings classes to improve debugging experience.
• Implemented GetDebuggerDisplay methods to provide concise object state information for debugging purposes.
• Changed reservedSettingNames from List to HashSet in RemoteSessionSettings for potential performance improvement.

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Changes walkthrough 📝

Relevant files

Enhancement

DriverOptions.cs Add DebuggerDisplay for DriverOptions class                            dotnet/src/webdriver/DriverOptions.cs Added DebuggerDisplay attribute to DriverOptions class. Implemented GetDebuggerDisplay method for concise object state representation. +38/-0    ReturnedCapabilities.cs Add DebuggerDisplay for ReturnedCapabilities class              dotnet/src/webdriver/Internal/ReturnedCapabilities.cs Added DebuggerDisplay attribute to ReturnedCapabilities class. Implemented GetDebuggerDisplay method to show browser and capability count. +12/-0    RemoteSessionSettings.cs Add DebuggerDisplay and optimize reservedSettingNames in RemoteSessionSettings dotnet/src/webdriver/Remote/RemoteSessionSettings.cs Added DebuggerDisplay attribute to RemoteSessionSettings class. Implemented GetDebuggerDisplay method for displaying browser and driver count. Changed reservedSettingNames from List to HashSet. +14/-1

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[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 Code Smell Trailing comma and space in the else branch return statement of GetDebuggerDisplay() method looks like a typo Performance Converting List to HashSet for reservedSettingNames may impact performance if Contains() is rarely called but items are frequently added

[qodo-merge-pro]

PR Code Suggestions ✨

Explore these optional code suggestions:

Category	Suggestion	Score
Possible bug	✅ Add null check to prevent potential null reference exception Suggestion Impact: The commit added a null check to mustMatchDriverOptions before accessing BrowserName, which aligns with the suggestion to prevent a potential NullReferenceException. code diff: - string browser = this.mustMatchDriverOptions.BrowserName; + string browser = this.mustMatchDriverOptions?.BrowserName; Add null check for mustMatchDriverOptions before accessing BrowserName to prevent potential NullReferenceException. dotnet/src/webdriver/Remote/RemoteSessionSettings.cs [358] -string browser = this.mustMatchDriverOptions.BrowserName; +string browser = this.mustMatchDriverOptions?.BrowserName; Apply this suggestion Suggestion importance[1-10]: 9 Why: Adding a null check is critical for preventing runtime NullReferenceException, as mustMatchDriverOptions could potentially be null. This is an important defensive programming practice.	9
Enhancement	✅ Remove unnecessary trailing characters in string formatting Suggestion Impact: The suggestion to remove the trailing comma and space in the return string of GetDebuggerDisplay() was implemented, improving code clarity. code diff: - return $"Additional Driver Count = {this.firstMatchOptions.Count}, "; + return $"Additional Driver Count = {this.firstMatchOptions.Count}"; Remove the trailing comma and space in the fallback return string of GetDebuggerDisplay() as it creates unnecessary formatting. dotnet/src/webdriver/Remote/RemoteSessionSettings.cs [364] -return $"Additional Driver Count = {this.firstMatchOptions.Count}, "; +return $"Additional Driver Count = {this.firstMatchOptions.Count}"; Apply this suggestion Suggestion importance[1-10]: 7 Why: The trailing comma and space in the debug display string serve no purpose and could be confusing. Removing them improves code clarity and correctness.	7
Performance	Optimize StringBuilder initialization with capacity estimation Pre-calculate the initial StringBuilder capacity based on expected content length to reduce reallocations. dotnet/src/webdriver/DriverOptions.cs [633] -StringBuilder builder = new StringBuilder(); +StringBuilder builder = new StringBuilder(64); Apply this suggestion Suggestion importance[1-10]: 3 Why: While pre-allocating StringBuilder capacity can improve performance by reducing reallocations, the impact here is minimal since the string being built is relatively small and this is debug-only code.	3

💡 Need additional feedback ? start a PR chat

[nvborisenko]

Hi @RenderMichael , your statements are absolutely correct. But let me correct main goal: ToString() should not be involved in json serialization. If we can achieve it, then everything becomes clear. Because of using DebuggerDisplay attribute to avoid performance issues looks strange.

[RenderMichael]

I wanted to be more careful, since changing a ToString() method is a breaking change. Even if Selenium doesn’t rely on it, maybe some users use it?

Maybe the break is acceptable (it should be), but the debugger changes do not lead to any behavior differences at all.

[nvborisenko]

I understand your motivation, but I don't like a way how it is achieved. We are mixing purposes for debugging, string representation and json serialization. It adds a complexity (which affects maintainability).

If we would resolve initial issue with ToString(), then everything would clear.

I am afraid I cannot accept this changes in context of "what and how we are trying to resolve it" - for me it is "workaround on top of workaround". Let's wait what others will say.

[RenderMichael]

For what it’s worth, this debugger display is in line with what other custom debugger displays look like. For example, dictionaries look like this (and these types are basically strongly-typed dictionaries).

I agree that without the heavy ToString(), these custom displays may not be necessary (I still like them) and the default {GetType().Name} would suffice.