[dotnet] Fix the issue when service wants to write into disposed stream

[nvborisenko]

User description

💥 What does this PR do?

Fix the issue when service wants to write into disposed stream.
Fix possible dual-blocking IO.

💡 Additional Considerations

This is core fix.

🔄 Types of changes

• Cleanup (formatting, renaming)
• Bug fix (backwards compatible)
• New feature (non-breaking change which adds functionality and tests!)
• Breaking change (fix or feature that would cause existing functionality to change)

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PR Type

Bug fix, Enhancement

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Description

• Fix disposed stream write issue in driver service

• Prevent dual-blocking IO during initialization

• Reorder disposal calls in Firefox service

• Clean up documentation comments

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Diagram Walkthrough

flowchart LR
  A["Driver Service Start"] --> B["Begin Output/Error Reading"]
  B --> C["Wait for Initialization"]
  C --> D["Fire Started Event"]
  E["Firefox Service"] --> F["Dispose Base First"]
  F --> G["Dispose Log Writer"]

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File Walkthrough

Relevant files

Bug fix

DriverService.cs Fix service initialization order                                                  dotnet/src/webdriver/DriverService.cs Reorder service initialization sequence Move output/error reading before waiting for initialization Prevent blocking IO during startup +5/-3      FirefoxDriverService.cs Fix disposal order and cleanup docs                                            dotnet/src/webdriver/Firefox/FirefoxDriverService.cs Remove unused parameter documentation Reorder disposal calls to dispose base class first Prevent writing to disposed stream +2/-3

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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 Event Ordering Moving OnDriverProcessStarted after WaitForServiceInitialization changes event sequencing; verify no consumers depend on the event being raised before initialization completes, and confirm no race with BeginOutput/ErrorReadLine. bool serviceAvailable = this.WaitForServiceInitialization(); DriverProcessStartedEventArgs processStartedEventArgs = new DriverProcessStartedEventArgs(this.driverServiceProcess); this.OnDriverProcessStarted(processStartedEventArgs); Dispose Ordering Disposing base first may dispose streams/event handlers that still reference logWriter; confirm no base dispose path reads/writes to logWriter after it's set to null. protected override void Dispose(bool disposing) { base.Dispose(disposing); if (logWriter != null && disposing) { logWriter.Dispose(); logWriter = null; } }

[qodo-merge-pro]

PR Code Suggestions ✨

Explore these optional code suggestions:

Category	Suggestion	Impact
Possible issue	Guard and harden async stream reads Wrap the asynchronous read starts in a try/catch and ensure they are only called once to avoid ObjectDisposedException or InvalidOperationException if the process exits immediately. Also short-circuit if the process has already exited after Start() to prevent reading from disposed streams. dotnet/src/webdriver/DriverService.cs [258-266] this.driverServiceProcess.Start(); -this.driverServiceProcess.BeginOutputReadLine(); -this.driverServiceProcess.BeginErrorReadLine(); +if (!this.driverServiceProcess.HasExited) +{ + try + { + this.driverServiceProcess.BeginOutputReadLine(); + this.driverServiceProcess.BeginErrorReadLine(); + } + catch (ObjectDisposedException) + { + // Process exited quickly; ignore as we'll fail initialization below. + } + catch (InvalidOperationException) + { + // Async read already started or stream unavailable; ignore safely. + } +} bool serviceAvailable = this.WaitForServiceInitialization(); DriverProcessStartedEventArgs processStartedEventArgs = new DriverProcessStartedEventArgs(this.driverServiceProcess); this.OnDriverProcessStarted(processStartedEventArgs); Apply / Chat Suggestion importance[1-10]: 8 __ Why: The suggestion correctly identifies a potential race condition where the process could exit before async reads are initiated, leading to exceptions. Adding a check for HasExited and a try-catch block significantly improves the robustness of the service startup logic.	Medium
	Unsubscribe from data events on dispose Unsubscribe from process OutputDataReceived/ErrorDataReceived before disposing logWriter and after calling base, to stop late-arriving events from using a now-null/disposed logger. This prevents race conditions during shutdown. dotnet/src/webdriver/Firefox/FirefoxDriverService.cs [279-288] protected override void Dispose(bool disposing) { base.Dispose(disposing); - if (logWriter != null && disposing) + if (disposing) { - logWriter.Dispose(); - logWriter = null; + if (this.IsRunning) + { + try + { + this.driverServiceProcess.OutputDataReceived -= this.OnDriverProcessDataReceived; + this.driverServiceProcess.ErrorDataReceived -= this.OnDriverProcessDataReceived; + } + catch + { + // Swallow any errors during teardown + } + } + + if (logWriter != null) + { + logWriter.Dispose(); + logWriter = null; + } } } Apply / Chat Suggestion importance[1-10]: 8 __ Why: This suggestion correctly identifies a potential race condition where OnDriverProcessDataReceived could be called after logWriter is disposed, causing a NullReferenceException. Unsubscribing from the events in Dispose is the correct pattern to prevent this.	Medium
Learned best practice	Dispose children before base Dispose managed resources owned by this class before calling the base class Dispose to avoid potential use-after-dispose scenarios. Move the base.Dispose(disposing) call to the end of the method. dotnet/src/webdriver/Firefox/FirefoxDriverService.cs [279-288] protected override void Dispose(bool disposing) { - base.Dispose(disposing); - if (logWriter != null && disposing) { logWriter.Dispose(); logWriter = null; } + + base.Dispose(disposing); } Apply / Chat Suggestion importance[1-10]: 6 __ Why: Relevant best practice - Use proper resource disposal ordering to avoid accessing disposed objects and to ensure deterministic cleanup.	Low
Update

[nvborisenko]

Ai reminds to unsubscribe, let me fix it.

[nvborisenko]

Yeah, made it before release.