Handle a null szPname field

[jkoritzinsky]

Fixes #75667

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Issue Details

---

Fixes #75667

Author:	jkoritzinsky
Assignees:	jkoritzinsky
Labels:	area-System.Speech
Milestone:	-

[danmoseley]

If you add a call before this line

runtime/src/libraries/System.Speech/tests/SynthesizeRecognizeTests.cs

Line 41 in 1d02519

synth.Speak(prompt);

to synth.SetOutputToDefaultAudioDevice() does it repro it? If so maybe throw that in this PR?

[jkoritzinsky]

@danmoseley should I start a backport for this PR?

[stephentoub]

/backport to release/7.0

[github-actions]

Started backporting to release/7.0: https://github.com/dotnet/runtime/actions/runs/3063572266

[stephentoub]

/backport to release/7.0-rc2

[github-actions]

Started backporting to release/7.0-rc2: https://github.com/dotnet/runtime/actions/runs/3063574386

[stephentoub]

@jkoritzinsky, were you able to repro the exception before the fix and validate it doesn't repro after?

[jkoritzinsky]

I wasn't able to repro it initially, but based on the stack trace this was the only possible location for the exception.

I'll try reproing it without the fix again if that will help for servicing.

[stephentoub]

It'd help both with servicing and with confidence that we actually fixed the problem.

[jkoritzinsky]

I can't get it to repro locally on my machine. It's possible I didn't configure something right on the Windows side as there's some Windows configuration for System.Speech that I had to go through before any of the tests would run.

[danmoseley]

This code is pretty dependent on OS state, thinking back to bugs we've seen. I know that it can depend on eg what voices you have installed for what cultures and other registry settings and maybe audio device configuration. Perhaps it would be OK if you can just set szPname to null in the debugger and then run.

[jkoritzinsky]

It looks like we won't even hit this code path if the following registry key isn't set: HKEY_CURRENT_USER\SOFTWARE\Microsoft\Speech\AudioOutput\DefaultTokenId. I'm not sure how to manually set that registry key, so I can't repro this locally. @danmoseley any chance you have steps I can follow to set up the right key/value? (The call on line 48 below is what leads to the code that caused the exception).

runtime/src/libraries/System.Speech/src/Internal/ObjectToken/SAPICategories.cs

Lines 31 to 57 in b707fd6

	internal static int DefaultDeviceOut()
	{
	int device = -1;
	using (ObjectTokenCategory tokenCategory = ObjectTokenCategory.Create(@"HKEY_CURRENT_USER\SOFTWARE\Microsoft\Speech\AudioOutput"))
	{
	if (tokenCategory != null)
	{
	string deviceName;
	if (tokenCategory.TryGetString(_defaultTokenIdValueName, out deviceName))
	{
	int pos = deviceName.IndexOf('\\');
	if (pos > 0 && pos < deviceName.Length)
	{
	using (RegistryDataKey deviceKey = RegistryDataKey.Create(deviceName.Substring(pos + 1), Registry.LocalMachine))
	{
	if (deviceKey != null)
	{
	device = AudioDeviceOut.GetDevicedId(deviceKey.Name);
	}
	}
	}
	}
	}
	}
	return device;
	}

[jkoritzinsky]

Figured out which control panel setting to set that key.

Repro'd locally without the fix and verified the fix locally.

[danmoseley]

Ha, yes there's an example of the zillion registry settings